Paleobiogeography of Miocene to Pliocene Equinae of North America ...

Paleobiogeography of Miocene to Pliocene Equinae of North America: A Phylogenetic Biogeographic and Niche Modeling Approach

A thesis presented to the faculty of the College of Arts and Sciences of Ohio University

In partial fulfillment of the requirements for the degree Master of Science

Kaitlin Clare Maguire June 2008

2 This thesis titled Paleobiogeography of Miocene to Pliocene Equinae of North America: A Phylogenetic Biogeographic and Niche Modeling Approach

by KAITLIN CLARE MAGUIRE

has been approved for the Department of Geological Sciences and the College of Arts and Sciences by

Alycia L. Stigall Assistant Professor of Geological Sciences

Benjamin M. Ogles Dean, College of Arts and Sciences

3 ABSTRACT MAGUIRE, KAITLIN CLARE, M.S., June 2008, Geological Sciences Paleobiogeography of Miocene to Pliocene Equinae of North America: A Phylogenetic Biogeographic and Niche Modeling Approach (195 pp.) Director of Thesis: Alycia L. Stigall The biogeography and evolution of the subfamily Equinae is examined using two separate but related analyses, phylogenetic biogeography and ecological niche modeling. The evolution of Equinae is a classic example of an adaptive radiation during a time of environmental change. Both analyses employed here examine the biogeography of the equine species to interpret how environmental and historical variables led to the rise and fall of this clade. Results determine climate change is the primary factor driving the radiation of Equinae and geodispersal is the dominant mode of speciation between regions of North America. A case study in the Great Plains indicates distributional patterns are more patchy during the middle Miocene when speciation rates are high than in the late Miocene, when the clade is in decline. Statistical results and distributional patterns show equine species tracked their preferred habitat throughout North America as climate changed in the Miocene. Approved: _____________________________________________________________ Alycia L. Stigall Assistant Professor of Geological Sciences

4 ACKNOWLEDGMENTS The completion of this thesis would not have been possible without the help and guidance of several people. I would like to thank the following people for providing data: B.H. Passey, J.D. Damuth, J.R. Thomasson and a special thanks to G.J. Retallack. I would also like to thank C.M. Janis and Y. Wang for pointing me in the right direction for data, R.C. Hulbert and J. Alroy for clarification with phylogenetic relationships in the clade, and R. Purdy for access to the collections at NMNH. A big thanks to Chris Dobel for assisting me with data collection. This research was funded by an Ohio University Geological Sciences Graduate Alumni Research Grant, GSA Grants-in-Aid Award, and OHIO Center for Ecology and Evolutionary Studies Fellowship. I would especially like to thank my advisor, Alycia Stigall for all of her help, guidance and support that has not only made me a better student, but a better professional. Thank you also to my committee members, Dan Hembree, Pat O’Connor and Keith Milam for reviewing parts of this thesis intended for publication and for all of their help and support along the way.

5 TABLE OF CONTENTS Page Abstract ............................................................................................................................... 3 Acknowledgments............................................................................................................... 4 List of Tables ...................................................................................................................... 8 List of Figures ..................................................................................................................... 9 Chapter 1: Introduction ..................................................................................................... 10 References..................................................................................................................... 14 Chapter 2: Paleobiogeography of Miocene Equinae of North America: A phylogenetic biogeographic analysis of the relative roles of climate, vicariance, and dispersal ........... 16 Abstract......................................................................................................................... 16 Introduction................................................................................................................... 17 Geologic and Paleoclimatic Framework....................................................................... 21 Evolutionary Framework .............................................................................................. 23 Materials and Methods.................................................................................................. 26 Taxa and geographic regions ................................................................................... 26 Analytical Biogeographic Method ............................................................................ 28 Results........................................................................................................................... 30 Speciation Patterns ................................................................................................... 30 Biogeographic Area Analysis ................................................................................... 31 Discussion..................................................................................................................... 33 Distributional Patterns ............................................................................................. 33

6 Vicariance Patterns .................................................................................................. 37 Geodispersal Patterns............................................................................................... 40 Comparison and Synthesis ........................................................................................ 42 Conclusions................................................................................................................... 43 References..................................................................................................................... 45 CHAPTER 3: Distribution of fossil horses in the Great Plains during the Miocene and Pliocene: An ecological niche modeling approach........................................................... 52 Abstract......................................................................................................................... 52 Introduction................................................................................................................... 53 Methods ........................................................................................................................ 57 Geographic and Stratigraphic Intervals ................................................................... 57 Species Occurrence Information............................................................................... 63 Environmental Data.................................................................................................. 64 Creation of Environmental Layers............................................................................ 72 Distribution Modeling............................................................................................... 73 Biogeographic Analyses............................................................................................ 77 Results and Discussion ................................................................................................. 81 Habitat Fragmentation ............................................................................................. 81 Habitat Tracking....................................................................................................... 83 Range Size vs. Survival ............................................................................................. 89 Regional Trends ........................................................................................................ 92 Conclusions................................................................................................................... 95

7 References..................................................................................................................... 97 Chapter 4: Conclusion..................................................................................................... 106 References................................................................................................................... 109 APPENDIX A: Vicariance and geodispersal matrix ...................................................... 110 APPENDIX B: Published references for geographic location data................................ 112 APPENDIX C: Species occurrence data for the great plains ......................................... 124 APPENDIX D: Original environmental data.................................................................. 143 APPENDIX E: Predicted species distribution maps....................................................... 186

8 LIST OF TABLES Page Table 1.Species modeled in the middle and late time slices............................................. 58 Table 2.Environmental data refereneces by variable........................................................ 59 Table 3.Environmental data for each grid box in the middle time slice ........................... 69 Table 4.Environmental data for each grid box in the late time slice ................................ 70 Table 5.Geographic ranges predicted for species from GARP modeling......................... 79 Table 6.Two-Sample T-Test comparing number of discrete populations per time slice.. 83 Table 7.Two-Sample T-Test comparing the area of a species’ geographic range in the Southern Great Plains per time slice................................................................................. 85 Table 8.Linear Regression Analysis of species longevity and the area of a species’ geographic range............................................................................................................... 90 Table 9.Kruskal Wallis Test comparing the area of a species’ geographic range verses species survivall across the Barstovian/Clarendonian Boundary ..................................... 90 Table 10. Kruskal Wallis Test comparing the area of a species’ geographic range verses species survivall across the Clarendonian/Hemphillian Boundary................................... 91 Table 11. Kruskal Wallis Test comparing the area of a species’ geographic range verses species survivall across the Hemphillian/Blancan Boundary ........................................... 91

9 LIST OF FIGURES Page Figure 1. Temporally calibrated cladogram of the Equinae..............................................18 Figure 2. Endemic geographic areas of the subfamily Equinae in North America analyzed in this study. ...................................................................................................................... 19 Figure 3. Area cladogram of the Equinae clade based on phylogenetic topology in Figure 1......................................................................................................................................... 19 Figure 4. Vicariance and geodispersal area cladograms derived from Lieberman-modified Brooks Parsimony Analysis.............................................................................................. 19 Figure 5. Great Plains study area with 1° x 1° grid boxes overlain.................................. 19 Figure 6. Examples of environmental variable interpolations. ......................................... 19 Figure 7. GARP predicted species distribution maps for Pseudhipparion gratum, Nannippus lenticularis, Nannippus aztecus, and Pseudhipparion peninsulatus. ............. 19 Figure 8. GARP predicted distribution maps for Astrohippus ansae and Dinohippus interpolatus in the late time slice ...................................................................................... 19 Figure 9. GARP prediction maps for Cormohipparion occidentale................................. 19 Figure 10. GARP predicted species distribution maps for P. mirabilis, and P. pernix and P. nobilis.. ......................................................................................................................... 19

10 CHAPTER 1: INTRODUCTION This thesis is a compilation of two separate, but related, analyses on the biogeography and evolution of Miocene and Pliocene fossil horses of the subfamily Equinae of North America. The Miocene record of fossil horse species includes a dramatic radiation in the number of species that has long been interpreted as a classic example of an adaptive radiation driven by changes in the climatic and vegetative regime during the Miocene (e.g., Simpson, 1951; MacFadden and Hulbert, 1988; Hulbert, 1993; Webb et al., 1995). While the evolutionary patterns in terms of phylogenetic relationships are well known (MacFadden, 1992; Hulbert, 1993; Kelly, 1995, 1998; Woodburne, 1996), no previous studies have applied quantitative biogeographic methods to analyze the geographic and ecological patterns of this radiation. The goal of this thesis is to examine equid biogeography quantitatively to determine how environmental and historical variables (i.e. climatic and tectonic changes) contributed to this radiation. Distribution patterns on both the continental and local scale are analyzed to allow assessment of both the regional and local results of the effects of these variables. As climate changes today, understanding how the same variables influenced the distribution and evolution of species in the past becomes important to understanding the current biodiversity crisis. The radiation of the subfamily Equinae occurred during the Miocene, a time of climatic, tectonic and environmental change (Webb et al., 1995). Temperatures rose from the Oligocene and reached a maximum in the Miocene of appromixmately 13° C for bottom water paleotempeartures at about 15-17 Ma (Cooke et al., 2008). Then

11 temperatures dropped dramatically as ice sheets formed over Antarctica (Zachos et al., 2001; Rocchi et al., 2006; Lewis et al., 2007) reaching modern Antarctic Intermediate Water temperatures at about 5.5°C (Cooke et al., 2008). The Cordilleran region on the western margin of North America was experiencing active uplifting, creating a rainshadow effect that caused increasing arid conditions in parts of central and western North America (Leopold and Denton, 1987; Hulbert, 1993). This climatic change resulted in a shift of vegetation cover in parts of North America as well. In the Great Plains and southwestern regions, leafy vegetation, such as trees and shrubs, was replaced by spreading grasslands (Wolfe, 1985; Leopold and Denton, 1987; Jacobs et al., 1999). This shift in vegetation style, however, did not occur in the coastal regions of North America, where leafy vegetation persisted in a more humid climate (Webb et al., 1995; Retallack 2007). The Equinae clade provides an example of a clade that radiated during a time of dramatic environmental change. The clade is appropriate for both phylogenetic and environmental niche based biogeographic analysis because the fossil record of its species is both abundant and well-sampled. Missing data in a biogeographic study can either represent true absence of the taxa in an area or it can be a product of under sampling. Abundant occurrence data is important for any biogeographic analysis in order to prevent false results from absence data. In addition, there is a large volume of literature on Equinae species regarding their phylogenetic relationships, morphological characteristics, diet, and relationship with the environment. Equinae, therefore, an excellent group of taxa

12 with which examine how changing historical and environmental conditions are related to evolutionary processes in a biogeographic framework. The two papers included in this thesis each examine separate but related aspects of the biogeography of the Equinae clade. The analyses focus on different geographic scales but both examine how environmental change affected the evolution of the clade. The first paper examines the phylogenetic biogeography of Equinae species from four regions of North America. This paper utilizes Lieberman-modified Brooks Parsimony Analysis (Lieberman, 2000) to determine whether specific speciation events within the clade are related to vicariance events, dispersal events, or both. The final output of the study examines whether clade level patterns developed due to cyclical geological events, such as climatic oscillations, or singular geological events, such as tectonic events. The second paper focuses on ecological controls on species level biogeographic patterns in the Great Plains region of North America. Individual species distributions are analyzed in order to understand how climatic change influenced the biogeographic patterns at the ecological level. Environmental niche modeling using a genetic algorithm is used to predict species distribution based on environmental parameters and known occurrence data. Species’ distributions are analyzed by size and pattern to compare shifting climatic and environmental variables. Two primary conclusions can be drawn from the analysis: how species ranges shifted due to climatic conditions and how this shifting affected evolutionary patterns. The combined results of both analyses conclude that the evolution of Equinae was driven by cyclical processes (climate change). At the regional scale, geodispersal

13 was the dominant mode of speciation. As climate changed, environmental barriers were rising and falling, leading to the radiation of the clade. At the local level, climate change resulted in habitat fragmentation evidenced by patchy distribution patterns. This resulted in niche partitioning and speciation within the Equinae clade. As climate changed, species tracked their preferred habitats. This pattern is observed at the regional and local scale as equids migrated from the Southwest to the Great Plains and then the Great Plains to the Gulf Coast. Despite habitat tracking, the decline of the Equinae clade began in the Late Miocene. The decline was a result of loss of habitat from climatic deterioration and due to reduced speciation rates as distributions became continuous and widespread.

14 References Hulbert, Jr., R.C., 1993. Taxonomic evolution in North American Neogene horses (Subfamily Equinae): the rise and fall of an adaptive radiation. Paleobiology 19 (2), 216-234. Jacobs, B.R., Kinston, J.D., Jacobs, L.L., 1999. The origin of grass-dominated exosystems. Annals of the Missouri Botanical Garden 86 (2), 590-643. Kelly, T.S., 1995. New Miocene horses from the Caliente Formation, Cuyama Valley Badlands, California. Natural History Museum of Los Angeles County, Contributions in Science 455, 1-33. Kelly, T.S., 1998. New Middle Miocene equid crania from California and their implications for the phylogeny of the Equini. Natural History Museum of Los Angeles County, Contributions in Science 473, 1-43. Leopold, E.B., Denton, M.F., 1987. Comparative age of grassland and steppe east and west of the northern Rocky Mountains. Annals of the Missouri Botanical Garden 74, 841-867. Lewis, A.R., Marchant, D.R., Ashworth, A.C., Hemming, S.R., Machlus, M.L., 2007. Major middle Miocene global climate change: evidence from East Antarctica and the Transantarctic Mountains. Geological Society of America Bulletin 119(11), 1449-1461. Lieberman, B.S., 2000. Paleobiogeography. Kluwer Academic/Plenum Publishers, New York, 208 pp. MacFadden, B.J., 1992. Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge University Press, Cambridge, England, 369 pp. MacFadden, B.J., Hulbert, Jr., R.C., 1988. Explosive speciation at the base of the adaptive radiation of Miocene grazing horses. Nature (London) 336, 466-468. Retallack, G.J., 2007. Cenozoic paleoclimate on land in North Amirca. The Journal of Geology 115, 271-294. Rocchi, S., Di Vincenzo, G., LeMasurier, W.E., 2006. Oligocene to Holocene erosion and glacial history in Marie Byrd Land, West Antarctica, inferred from exhumation of the Dorrel Rock intrusive complex and from volcano morphologies. Geological Society of America Bulletin 118, 991–1005.

15 Simpson, G.G., 1951. Horses: The Story of the Horse Family in the Modern World and through Sixty Million Years of History. Oxford University Press, Oxford, England, 247 pp. Webb, S.D., Hulbert, Jr., R.C., Lambert, W.D., 1995. Climatic implications of largeherbivore distributions in the Miocene of North America. In: Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle, L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 91-108. Wolfe, J.A., 1985. Distribution of major vegetation types during the Tertiary. Geophysical Monograph 32, 357-375. Woodburne, M.O., 1996. Reappraisal of the Cormohipparion from the Valentine Formation, Nebraska. American Museum of Novitiates 3163, 56 pp. Zachos, J.C., Pegani, M., Stone, L., Thomas, E., Billups, K., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292, 686-693.

16 CHAPTER 2: PALEOBIOGEOGRAPHY OF MIOCENE EQUINAE OF NORTH AMERICA: A PHYLOGENETIC BIOGEOGRAPHIC ANALYSIS OF THE RELATIVE ROLES OF CLIMATE, VICARIANCE, AND DISPERSAL

Abstract The horse clade Equinae underwent a major radiation during the Miocene in North America, diversifying from one species, Parahippus leonensis, to 70 species. This radiation has been linked to climatic and vegetation changes that occurred in North America during this time. However, the relationship between climate change and speciation has not previously been studied quantitatively using phylogenetic biogeography. Distribution and age-range data were collected for all North American species within eighteen equine genera through a literature review and use of the Paleobiology Database. Distribution data were analyzed using the Lieberman-modified Brooks Parsimony Analysis (LBPA) to determine patterns of vicariance and geodispersal, using four constrained biogeographic regions within North America in the analysis: the Great Plains, the Southwest, the Gulf Coast and the Southeast. Results from the LBPA indicate that speciation by dispersal was much more common in the evolution of the clade than speciation by vicariance. Patterns of distribution are congruent with geolgocial events, such as uplift of the Rocky Mountains, and climatic conditions, such as the change from a warm and moist to cool and arid climate during the Miocene. Well supported vicariance and geodispersal trees derived from the LBPA analysis are largely

17 congruent with each other, indicating that cyclical events, in particular, climate change during the Miocene influenced the radiation of the clade.

Introduction The coevolution of the Earth and its biota has long been studied to investigate speciation and the process of evolution (Wallace, 1855; Valentine and Moores, 1970, 1972; Mayr,1982; Tiffney and Niklas, 1990; Lieberman, 2000 ). Depending on where and when an organism lived, large scale Earth history events (orogenesis, continental fragmentation) or climatic change may have resulted in environmental changes which led to the divergence of populations and ultimately speciation. By analyzing the distribution of the species within a phylogenetic framework, it is possible to elucidate the roles of climatic change and/or Earth history events influencing speciation (Lieberman, 2000). Deciphering the primary driver of speciation and subsequent evolution within a lineage provides insight into how these taxa interacted with their environment in the past, and importantly, may predict how they will react to environmental changes in the future. The dramatic radiation of Equinae is often cited as a classic example of an adaptive radiation, reflecting rapid speciation in response to environmental change (e.g., MacFadden and Hulbert, 1988; Hulbert, 1993). During the Early Miocene, this clade consisted of a single species, Parahippus leonensis, but by the Late Miocene had diversified into 70 named species belonging to 18 named genera (Fig. 1) (MacFadden, 1992). This diversification occurred contemporaneously with

Figure 1. Temporally calibrated cladogram of the Equinae. Phylogenetic relationships adapted from Hulbert (1993) and modified using Kelly (1995, 1998), Prado and Alberdi (1996), and Woodburne (1996). ICS temporal scale from Gradstein et al. (2004) and North American Land Mammal Ages (NALMA) from Alroy (2003). Narrow vertical lines indicate ghost lineages, wharas bold vertical lines indicate the recorded range. Stratigraphic distributions of data derived from sources in Appendix B. Taxa abbreviations: Plio.= Pliohippus, Acrit. = Acritohippus, Cal. = Callippus, Pro. = Protohippus, Neo. = Neohipparion, Pseud. = Pseudhipaprion, Hipp. = Hipparion, Nann. = Nannippus.

environmental changes resulting from climatic cooling and the spread of grasslands across North America. Whereas the general patterns, including phylogenetic relationships, associated with the Equinae diversification are well-understood, prior analyses have not utilized quantitative paleobiogeographic methods to examine the relationship between biogeographic and cladogenetic patterns in the group. This study quantitatively assesses paleobiogeographic patterns within North American members of the Equinae clade during their Miocene radiation using phylogenetic biogeography. The Equinae clade is an excellent candidate for a phylogenetic biogeographic study because evolutionary relationships between the species within the clade are well constrained (MacFadden, 1998; Hulbert, pers. communication 2007) (Fig. 1) and the fossil record of horses is densely sampled in North America during this interval (MacFadden, 1992). These two factors combine to create a strong evolutionary and taphonomic framework in which to examine biogeographic response to climate change. In particular, I evaluate (1) the dominant mode of speciation apparent in the clade, (2) the relationship among biogeographic areas inhabited, and (3) the relative roles of climatic versus tectonic events during the evolution of the group. Determining species ranges and distributions within a phylogenetic framework will provide additional insight into the radiation of Equinae during climate change and the subsequent extinction of the clade. A phylogenetic biogeographic approach to studying the distribution of species can reveal patterns of speciation driving the evolution of the clade: divergence and speciation

20 (vicariance) as well as range expansion and dispersal (geodispersal). Speciation by vicariance occurs when a parent population is broken into two or more populations due to the introduction of a physical barrier such as orogenic uplift or tectonic rifting zones. Fragmentation of the population leads to reproductive isolation and eventually the population evolves into two separate species (Mayr, 1942; Lieberman, 1997). Speciation by geodispersal occurs when a parent population expands its range as barriers fall and then becomes fragmented when the same or new barriers rise again, leading to reproductive isolation and speciation (Lieberman and Eldredge, 1996). Speciation by geodispersal, therefore, is due to cyclical processes, with the rising and falling of barriers. It is an active mode of speciation in which the organisms have migrated, whereas vicariance is a passive mode of speciation. During the Miocene, terrestrial clades may have speciated due to vicariance by such processes as mountain uplift, introduction of new waterways, or habitat fragmentation due to climate change. Since there were no cyclical tectonic events in North America during the Neogene, terrestrial clades may have speciated by geodispersal from the fragmentation, rejoining, and shifting of habitat due to climate change. Phylogenetic biogeographic analysis, and in particular Lieberman-modified Brooks Parsimony Analysis (LBPA), the methodology used herein, is effective in interpreting the underlying factors, such as tectonic events and climate change, driving the speciation of a clade (Lieberman, 1997). Moreover, the impact of climate change on speciation can also be analyzed by comparing the geographic ranges of species with changes in the climate (Stigall and Lieberman, 2006). Whereas this method has

21 previously been applied to marine invertebrates (Lieberman and Eldredge, 1996; Lieberman, 1997; 2000; Stigall Rode and Lieberman, 2005) and fossorial reptiles (Hembree, 2006), this represents the first application of the method to mammals.

Geologic and Paleoclimatic Framework The position of the North American plate during the Miocene was similar to its present geographic position. Significant tectonic activity occurred along the western margin of the continent including uplift of the Rocky Mountains, extension resulting in the Basin and Range province, and volcanic eruptions in the Northwest (Cole and Armentrout, 1979; Prothero, 1998). Although the eastern portion of the continent was tectonically quiescent, this region was heavily influenced by fluctuating sea levels. For example, early in the Miocene, sea level was approximately 20 m higher than present (Kominz et al., 1998). Low-lying parts of the continent, like Florida and the Gulf Coast were repeatedly inundated by transgressive events (Scotese, 1998). Overall, sea level dropped by the Late Miocene, exposing Florida and parts of the Gulf Coast (Kominz et al., 1998). From the Miocene into the Pliocene climate fluctuated with an overall trend changing from warm and humid toward cool and dry (Barron, 1973; Partridge et al, 1995, Zachos et al., 2001). Temperatures increased from the cooler Oligocene into the Miocene and peaked at 17 Ma (Woodruff et al., 1981; Prothero, 1998). About 15 Ma, during the Middle Miocene, ice sheets formed permanently on Antarctica, causing cooling in North America (Zachos et al., 2001; Rocchi et al., 2006; Lewis et al., 2007). In addition, a large

22 rain shadow effect developed in the Great Plains and southwestern regions of North America due to the uplift of the Cordilleran region including the Cascade and Sierra Nevada Ranges (Leopold and Denton, 1987; Hulbert, 1993). Moisture levels decreased in North America due to both the rain shadow effect (Woodruff et al., 1981; Zubakov and Borzenkova, 1990) and global cooling (Leopold and Denton, 1987). Around 8 Ma, North America experienced a brief warming trend and then cooled again during the Messinian (Hemingfordian) glaciation (Prothero, 1998). The fluctuating and changing climate created a mixture of vegetative habitats across North America. Axelrod (1985) and Leopold and Denton (1987) suggest a subtropical mesic climate and vegetation in North America during the Early Miocene. Savanna and grassland habitats increased throughout the Miocene due to cooling and the rain shadow effect. This transition included an increase in grasslands with lower productivity. Isotopic evidence from mammalian tooth enamel reveals a shift from C3based savannas to C4-based grasslands during the Miocene (Cerling, 1992; Cerling, et. al., 1993; Wang et al., 1994). By the Pliocene, central North America was covered in a mostly treeless prairie (Webb et al. 1995). A variety of habitats, therefore, existed in North America during the Miocene from grasslands in the Great Plains and swamps along the Gulf Coast to arid regions in the Southwest. This is in contrast to earlier times in the Cenozoic when vegetative regimes were not as extreme through out North America due to consistent temperatures and climate across the continent. Changing climate led to fragmentation and shifting of habitats, resulting in a diverse assemblage of vegetative regimes in each region. In each of the regions, a range of vegetative habitats existed that

23 shifted as the climate changed. These habitats supported a diverse group of browsers, grazers and mixed-feeders (Webb, 1983). The climate change from warm and humid to cold and dry was initiated by both tectonic events, such as uplift in the Cordilleran region, and the onset of continental glaciations over Antarctica. On the timescale of this study (approximately 15 million years), however, the primary mechanism fluctuating was climate and not tectonic processes. To clarify, geological conditions of the Miocene refer to those described in this section (i.e., uplift in the Rocky Mountains and Cordilleran regions, sea level). Climatic conditions refer to the changing climate that resulted in changing vegetations throughout North America during the Miocene.

Evolutionary Framework The Miocene radiation of the Equinae clade was associated with significant changes in both the dentition and aspects of the locomotory apparatus (MacFadden, 1992). The basal genus Merychippus, a taxon which mesodont dentition, radiated between 18 and 15 Ma (Hemingfordian) (Hulbert, 1993). This was during the warmest period of the Miocene when vegetation consisted primarily of riparian forests, deciduous open forests, and wooded, semi-open savanna (Axelrod, 1985) that supported browsing species with mesodont dentition. The second radiation was between 15 and 12 Ma, in which the dominant taxa were hypsodont species of the tribes Hipparionini, Protohippini and Equini. Hypsodont species richness became greater than that of mesodont species (Hulbert, 1993), with mesodont taxa becoming extinct by ~11 Ma. This taxonomic shift

24 corresponds with the first two cooling events of the Miocene at 15.3-13.5 and 12.8-12.3 Ma (Hulbert, 1993) that led to a decrease in rainfall and a shift from woodland to grassland habitats (Axelrod, 1985). Hulbert (1993) attributed the turnover from mesodonty to hypsodonty to the climate and vegetation changes. The subfamily’s diversity reached a peak of 13 genera during the Clarendonian (11.5-9 Ma.) with a mixture of mesodont and hypsodont forms (Hulbert, 1993). By the middle of the Pliocene, however, only three Equinae genera remained, all exhibiting extreme hypsodonty. And by the end of the Pleistocene all genera except the modern Equus had become extinct (Webb, 1984). The evolution of taxa in response to climate during the Miocene has been well documented for equids (e.g., Shotwell, 1961; Webb, 1977, 1983; Stebbins, 1981; Janis, 1984, 1989; Thomasson and Voorhies, 1990). Horses have been cited as a classic example of evolution in the fossil record (ex., Marsh, 1879; Matthew, 1926; Stirton, 1940; MacFadden, 1992) and these studies demonstrate a clear link between climate change and evolution (e.g., Simpson, 1951). Previous biogeographic studies of horses have ranged from analyses of local patterns, such as in the Great Basin (e.g., Shotwell, 1961), to global surveys, hypothesizing that horses originated in North America and later dispersed to Europe and Asia (e.g., Lindsay et al., 1979; Lindsay et. al., 1984; MacFadden, 1992; Opdyke, 1995). Whereas these studies provide an excellent framework for examining the correlation between the diversification of the Equinae and environmental change, none has analyzed spatial distributions in a phylogenetic framework or applied quantitative biogeographic methods.

25 The major radiation of the Equinae clade during the Miocene has been attributed to the spread of grasslands. The classic story, however, has been augmented in recent years. For example, original hypotheses of orthogenetic evolution of the clade (e.g., Simpson, 1951), have been dismissed with the discovery of the tridactyl Nannipus, Neohipparion and Cormohipparion living in the Late Miocene with the “advanced” monodactlys (MacFadden, 1984, 1998). In addition, while the level of hypsodonty is often considered a proxy for browsing vs. grazing lifestyles (Kowalevsky, 1874; Matthew, 1926; Simpson, 1951, Stebbins, 1981), other studies have demonstrated that the dentition of a horse species is not always conclusive evidence for the type of vegetation in their diet (Stirton, 1947; Fortelius, 1985; Janis, 1988) and, therefore, cannot be used as the sole proxy for vegetation types. Stromberg (2006) advised against using tooth morphology alone to reconstruct habitat change due to inconclusive evidence regarding whether hypsodonty was an adaptive characteristic. The adaptation and speciation of this clade is more complex than originally thought. It is understood that environmental changes caused by climate fluctuations and vegetation change influenced the radiation of the clade (e.g., Hulbert, 1993; Webb, et al., 1995). Here I assess this claim and elucidate the details of the pattern by examining and statistically analyzing distributional data to better understand environmental influences on equine speciation.

26 Materials and Methods Taxa and geographic regions The phylogenetic hypothesis of equine relationships used in this study is adopted primarily from Hulbert (1993) and amended with relationships presented in Kelly (1995, 1998), Prado et al. (1996), and Woodburne (1996) (Fig. 1). Distribution data for included taxa were compiled from the primary literature, the Paleobiology Database (www.paleodb.org), and the National Museum of Natural History (NMNH). A complete list of referenced studies is included in Appendix B. To assess biogeographic patterns North America was divided into four areas of endemism (Fig. 2): the Southeast, the Gulf Coast, the Great Plains, and the Southwest. Areas of endemism were defined based on previous biogeographic divisions of the clade (Webb and Hulbert, 1986; Hulbert, 1987; Hulbert and MacFadden, 1991; Webb et al., 1995) and the presence of natural barriers (either climatic or geographic) on the North American plate during the Miocene. Species distribution data used in this study are congruent with the four areas of endemism used in previous studies. Additional areas of endemism may have existed, but the fossil record of those regions is too sparse to include in this analysis. Fossil Equinae are known from the Northwestern region of North America (e.g. Oregon, Idaho) and the Northeastern region (North Carolina and Delaware). The remains of only four species were located in the Northwest and only two species in the Northeast. When areas of endemism with only a few species are incorporated into phylogenetic biogeographic analyses, insufficient character data are present in the data matrix for these areas, and the optimization procedure cannot assess

27 correctly their placement in the parsimony analysis. These areas will simply place out at the base of the reconstructed area cladograms, thereby providing no information

Figure 2. Endemic geographic areas of the subfamily Equinae in North America analyzed in this study. The Southeast area includes sites in Florida. The Gulf Coast area stretches along the coast from Florida to the Mexican border. The Great Plains area begins approximately 400 km north of the Gulf Coast and stretches on the eastern side of the Rocky Mountains through Texas, New Mexico, Oklahoma, Kansas, Nebraska, Colorado, Wyoming, North and South Dakota, and Montana. The Southwest region included locations west of the Rocky Mountains in New Mexico, Arizona, California, Nevada, and Utah. The grey region represents the Rocky Mountain range during the Miocene.

28 (Lieberman, 2000; Stigall Rode and Lieberman, 2005). Consequently, I excluded these areas from this analysis due to methodological limitations.

Analytical Biogeographic Method Lieberman-modified Brooks Parsimony Analysis (LBPA) as described in Lieberman and Eldredge (1996) and Lieberman (2000) is the phylogenetic biogeographic method employed in this study. This method was selected because it is designed to resolve both vicariance and geodispersal patterns as well as assess the relative impact of cyclic versus singular events on the biogeographic history of a clade. Whereas other analytical methods for phylogenetic biogeography exist, they either cannot detect geodispersal or require simultaneous analysis of multiple clades (see discussion in Stigall, 2008). LPBA has been successfully used to resolve biogeographic patterns in the fossil record during intervals in which the primary driver of biogeographic patterns included both climatic oscillations (e.g., Lieberman and Eldredge, 1996; Stigall Rode and Lieberman, 2005) and tectonic events (Lieberman, 1997; Hembree, 2006). The methodology of this analysis is explained in detail in Lieberman (2000) but a brief discussion is presented here. The first step in the analysis is to convert the phylogenetic tree of Equinae into an area cladogram by replacing taxon names with the areas of endemism in which each species occurred. Biogeographic states for the internal nodes are optimized using Fitch Parsimony (Fitch, 1971). The cladogram based on Hulbert (1993), Kelly (1995, 1998) and Woodburne (1996) is shown as an area cladogram with optimized nodes in Figure 3. Two matrices, a vicariance matrix and a

29 geodispersal matrix, are coded for parsimony analysis from the area cladogram. In both matrices, areas of endemism are treated as taxa, whereas individual nodes and branches of the area cladogram are coded as characters (see Appendix 1). The two matrices are then evaluated separately using parsimony and provide different information about the relationship between the areas of endemism. The vicariance matrix is used to ascertain vicariance patterns within the area cladogram. In coding the matrix, an ancestral area is added for character polarization and is coded 0 for all character states. The biogeographic state of each node or terminus is coded as 0 when it is absent from an area and 1 if present. If a node represents a derived speciation event due to range contraction (vicariance) it is coded 2, which is treated as an ordered character state. The matrix was analyzed with PAUP 4.0b10 (Swofford, 2002) under an exhaustive search to determine the most parsimonious tree. The vicariance tree indicates the relative timing of separation for the four areas. Areas that group most closely on the tree were separated most recently by a barrier, such as orogenic uplift or habitat fragmentation. In contrast, areas more distally related on the tree were separated by a barrier more ancestrally. The second analysis examines geodispersal events across the clade. A matrix was coded with geodispersal events, similarly to the matrix for vicariance. Descendant taxa that occupy novel or additional areas of endemism are coded as a derived presence (2). The matrix was analyzed with PAUP 4.0b10 in the same way as for the vicariance matrix. The geodispersal tree indicates the relative timing that dispersal occurred between

30 areas. It demonstrates which areas were most recently connected, thereby allowing dispersal between them, and which ones were connected more ancestrally. Comparison of the two tree topologies indicates whether deterministic events, such as tectonic events, are driving the evolution of a clade or whether cyclical events, such as oscillatory climate change, are affecting its evolution. Congruent tree topologies illustrate that the order in which barriers arose is the same order in which they fell. Consequently, if the vicariance and geodispersal trees exhibit congruent topologies, then cyclical events have influenced the resulting biogeographic patterns. Conversely, if the trees are incongruent, then geodispersal and vicariance events did not occur between regions in a cyclical pattern (or at least are not cyclical on a timescale effecting speciation). Instead, singular events influenced the evolution of the clade (Lieberman and Eldredge, 1996; Lieberman, 1997).

Results Speciation Patterns Analysis of the biogeographic optimization provides the opportunity to assess mode of speciation. In cladogenetic events where the descendant species occupies only a subset of a larger ancestral range, speciation is interpreted to occur by vicariance. Conversely, when descendant species colonize areas additional to or distinct from the ancestral species, speciation is interpreted to result from dispersal. Speciation by dispersal is the primary mode of speciation across this clade (Fig. 3). Of cladogenetic

31 events where speciation mode could be assessed, there were 47 speciation events by dispersal and only 9 speciation events by vicariance. The overall pattern of biogeographic evolution in this clade can also be assessed from the area cladogram (Fig. 3). Parahippus leonensis and “Merychippus” gunteri, the ancestral species, lived primarily along the Gulf Coast and Southeast. However, the Equinae clade began its radiation further inland in the Great Plains. The three tribes of the Equinae clade (Equini, Protohippini and Hipparionini) diversified in three different areas of North America. The tribe Equini separated from the other two tribes first and diversified in the Southwest. Then the tribe Protohippini divided from the tribe Hipparionini. Ancestors of the tribe Protohippini continued to diversify in the Great Plains as well as along the Gulf Coast. The tribe Hipparionini continued to speciate in the Great Plains (Fig. 3). Later, however, species in each tribe dispersed from their ancestral regions into other areas.

Biogeographic Area Analysis The vicariance analysis produced a single most parsimonious tree (Fig. 4A). The consistency index (0.821), a measure of homoplasy, is statistically significant (p < 0.05) and indicates strong tree support (Sanderson and Donoghue, 1989; Klassen et al., 1991). The g1 statistic (g1 = - 0.214) indicates the tree length distribution is skewed to the left, and shows a significant phylogenetic signal at the level of p < 0.05 (Hillis and Huelsenbeck, 1992). The Great Plains and Southwest are most closely related indicating that a vicariance event created a barrier between them most recently. Ancestral to this

Figure 3. Area cladogram of the Equinae clade based on phylogenetic topology in Figure 1. Areas of endemism from Figure 2 labeled as: 1 – Southeast, 2 – Gulf Coast, 3 – Great Plains, 4 – Southwest. Circles indicate character number in the data matrix (Appendix A). Speciation at nodes identified as: V = vicariacne event, or D = dispersal event. 32

33 event, the Southeast was separated from the Great Plains and Southwest by a vicariant event. The Gulf Coast was separated from all three of the areas ancestrally. The geodispersal analysis also produced a single most parsimonious tree (Fig. 4B). The consistency index (0.805) and g1 (g1 = 0.148) are statistically different from random (p < 0.05) (Sanderson and Donoghue, 1989; Klassen et al., 1991; Hillis and Huelsenbeck, 1992), indicating strong tree support. The Gulf Coast and Southeast are closely related as well as the Great Plains and Southwest. Dispersal between these subregions occurred ancestrally. The topologies of the vicariance and geodispersal trees are largely congruent (Fig. 4). The primary difference between them is the relative relationship of the Southeast. In the geodispersal tree the Southeast is most closely related to the Gulf Coast; whereas in the vicariance tree the Southeast is more closely related to the Great Plains/Southwest than to the Gulf Coast. The geodispersal tree represents a clear division between the Great Plains/Southwest and the Gulf Coast/Southeast whereas the vicariance tree represents a relative progression of separation between all four regions. The Great Plains and Southwest, however, have a strong relationship on both trees.

Discussion Distributional Patterns The dominant mode of speciation within the Equinae clade is dispersal (Fig. 3) This is consistent with the migratory life habits of horses. The ancestral Parahippus leonensis did not breed seasonally or migrate, most likely because its habitat was

Figure 4. Vicariance and geodispersal area cladograms derived from Lieberman-modified Brooks Parsimony Analysis of Appendix A. (1) Vicariance tree; length is 181 steps, consistency index is 0.821, and g1 statistic is -0.214. (2) Dispersal tree; length is 231 steps, consistency index is 0.805, and the g1 statistic is 0.148.

34

35 consistent year round (Hulbert, 1984). Hyposodont horses, however, did migrate to exploit food resources and did breed in a seasonal environment (Van Valen, 1964; Voorhies, 1969). Studies of the global biogeographic distribution of the clade apply the mode of dispersal to explain their migration from North America to Europe and Asia through the Neartic (Lindsay et. al., 1984; Opdyke, 1995). The few vicariant events in Figure 3 are either related to the isolation of the Southwest region or the climatic deviation between the Gulf Coast and Great Plains areas. These events likely resulted from tectonic uplift in the west and differences in vegetation types in the east, respectively, and will be discussed in more detail below. The area cladogram and distribution of Equinae is consistent with Miocene tectonics in North America. For example, species are distributed in areas of the Florida Platform that were above sea level during the Miocene (Appendix B). Species are also distributed in areas of central New Mexico where the Rocky Mountain range had a narrower expanse during the Neogene compared to northern parts of its range (Trimble, 1980). The narrower expanse provided an area of passage between the Southwest and Great Plains regions in New Mexico during the Miocene. Conversely, no taxa were recorded from areas in the northern Rocky Mountains where the mountains had a wider expanse (Appendix B). The ancestral biogeographic states and the topology of the area cladogram show patterns of speciation that are consistent with the climate and distribution of vegetation during the Miocene. Ancestral taxa, Parahippus leonensis and Merychippus gunteri, inhabited the Gulf Coast regions (Fig. 3). However, none of the basal equid nodes

36 diversified there. The consistently moist conditions of the Gulf Coast provided a stable habitat that may have reduced opportunities for allopatric differentiation and inhibited the speciation of equid ancestors in the area. The Protohippini was the only tribe to diversify in the Gulf Coast area whereas the tribes Hipparionini and Equini speciated in the changing and fragmented habitats of other regions in North America (Fig. 3). Changing climatic conditions led to altered vegetation regimes in North America, but this was affected differently in the areas of endemism considered herein. The Gulf Coast and Southeast areas continued to include browsing habitats after the Great Plains and Southwest regions transitioned into arid grasslands (Wolfe, 1985). The Gulf Coast region became a refuge for taxa that became extinct in the Great Plains (Webb et al., 1995). Species such as Cormohipparion emsliei, Pseudhipparion simpsoni and Nannippus aztecus, tridactyls belonging to the tribe Hipparionini and adapted for browsing and selective grazing, survived in the Gulf Coastal regions long after becoming extinct in the Great Plains and Southwest (Webb and Hulbert, 1986; Webb et al., 1995). Ancestral members of the tribe Hipparionini were distributed in the Great Plains (Fig. 3). Several of the terminal taxa, however, occupied the Gulf Coast and Southeast areas indicating a movement to the warmer areas. The area cladogram (Fig. 3) expresses the refuge characteristic of the moist coastal regions. The general distribution of taxa throughout North America expressed in the area cladogram is closely related to the morphology of the Equinae species (Fig. 3). Although it has been demonstrated that monodactyl and tridactyl species were sympatric in North America (MacFadden, 1992), limb morphology was found to vary between different

37 areas and, consequently, vegetation types (Fig. 3). The tribe Equini that contains the dominantly monodactyl genera Astrohippus, Dinohippus, and Equus diversified in the Great Plains area (Fig. 3). Tridactyl genera of the tribe Hipparionini (e.g. Cormohipparion and Nannipus) diversified in the Great Plains but were the more common taxa in the Southeast. The tribe Protohippini contained tridactyl genera that diversified along the Gulf Coast. According to Renders (1984), tridactyl limb morphology provided more traction in muddy substrates. Muddy substrates were more abundant in warm humid areas of the Gulf Coast regions as opposed to the arid conditions of the Great Plains (Retallack, 2007). Although monodactyl and tridactyl species lived in the same endemic areas, they did occupy different ecological niches within those regions (MacFadden, 1992). Shotwell (1961) determined that the tridactyl horses preferred a mosaic of savanna and forest habitats of the northern Great Basin. As the grasslands became more widespread in the Great Basin, monodactyl horses became dominant (Shotwell, 1961).

Vicariance Patterns The vicariance tree indicates the relative order in which areas of endemism were separated by vicariance events. The relative order presented in Figure 4A is congruent with the interpreted geologic and climatic conditions of the Miocene in North America. The Southwest and Great Plains were separated most recently by a barrier (Fig. 4A). This separation is related to the final phase of uplift in the Rocky Mountains, which began in the Miocene following a tectonic quiescent period from the Cretaceous through the

38 Oligocene (Effinger, 1934; Frazier and Schwimmer, 1987). This slow and gradual uplift during the late Cenozoic persisted into the Pliocene. During the Miocene, the Southwest and Great Plains had different vegetation due to the uplift (Leopold and Denton, 1987). A rain shadow resulted in drier conditions east of the Rocky Mountains, thereby creating a vegetative difference between the two regions. East of the Rocky Mountains vegetation consisted of deciduous open forests ad prairie. To the west of the mountain range, deciduous hardwood forests and swamps dominated the vegetation (Leopold and Denton, 1987). Although grasses were present west of the Rocky Mountains in the Early Miocene, their abundance was not significant. Leopold and Denton (1987) attribute the difference in abundance to the inability of grasslands to spread across the mountainous barrier and the montane conifer forest that occupied the mountainous terrain. Grasslands became sporadically abundant west of the Rocky Mountains during the Blancan (Pliocene) when they spread from the northern Great Plains as they adapted to a summerdry climate from a summer-wet climate. The Southeast branches from the tree next (Fig. 4A). Its position here on the vicariance tree is probably a result of pre-Miocene sea level fluctuations. As the amount of exposed land of the Florida Platform varied, populations were divided. Leading into the Miocene, the Gulf Trough separated Florida from the continent (Randazzo and Jones, 1997). Through the Neogene, sediment shed from the North America continent filled in the trough and made Florida contiguous with the North American continent, thereby allowing dispersal of the ancestral species. The early vicariant events, however, are represented by the ancestral location of the Southeast on the vicariance tree.

39 The Gulf Coast region branches off ancestrally on the vicariance tree because there were no tectonic barriers between it and the Great Plains/Southwest areas (Fig. 4A). It acted as a passage way between the Southwest and Great Plains, and the Southeast (Fig. 4A). There were no physical barriers in the Gulf Coast region restricting dispersal the Mississippi River had not developed to its current size yet (Scotese, 1998). During the Early Miocene vegetation supported by a warm and humid climate was present in all four areas of endemism (Axelrod, 1985; Wolfe, 1985). A relatively quiescent tectonic setting combined with a stable flora allowed dispersal between the northern (Great Plains) and coastal areas (Gulf Coast and Southeast) by early members of the clade. These areas do not form a polytomy, however, because a climatic and vegetative difference developed between the northern and coastal areas during the midlate Miocene. Although Axelrod (1985) describes the environment of the entire Great Plains region during the Miocene as wooded grasslands with semi-open grassy forests and patchy grasslands, Retallack (2007) discusses a moisture gradient in the Great Plains from Montana to Nebraska and Kansas. Paleosols from Montana during the Miocene have weak pedogenic structure, low clay content, limited chemical weathering, and shallow calcic horizons indicating an arid environment (Retallack, 2007). Such paleosols represent aridic conditions from the rain shadow caused by the uplift in the Cordilleran region. Paleosols developed in Nebraska and Kansas during the Miocene exhibit fewer calcareous nodules and a higher clay content indicative of higher levels of precipitation (Retallack, 1983, 1997). Paleosols in Oregon from the Miocene also have greater clay content and fewer calcareous nodules. Retallack (2007) interpreted that the difference in

40 paleosols among these regions is due to the proximity of Nebraska, Kansas and Oregon to the maritime air masses from the Gulf and Pacific Coasts early in the Cenozoic. The relative separation of the endemic areas is consistent with the tectonic and climatic history of the North American continent during the Miocene. Vicariance events such as uplift in the western United States, isolation of Florida, and vegetational gradients have influenced the evolution of the Equinae clade.

Geodispersal Patterns The geodispersal tree indicates the relative time in which dispersal occurred between the endemic areas. Relationships within the geodispersal tree are congruent with the tectonic and climatic events of the Miocene as well. The close association between the Great Plains and Southwest on the geodispersal tree indicates that species dispersed several times between these two regions (Fig. 4B). As discussed previously, a corridor existed through the Rocky Mountains during the Miocene that allowed dispersal across the southern part of the mountain range (Trimble, 1980). Forty-three percent of the species in the Great Plains also lived in the Southwest compared to the 24% that also lived in the Gulf Coast area. Although both the Southwest and Gulf Coast are proximal to the Great Plains region, dispersal occurred more frequently between the Great Plains and Southwest than with the Gulf Coast. A physical barrier (i.e., Rocky Mountains) separated the Great Plains and Southwest (Cole and Armentrout, 1979; Trimble, 1980), whereas a climatic barrier separated the Great Plains and Gulf Coast (Retallack, 2007). Based on the

41 available data, the climatic barrier appears to be more influential than the physical barrier. The close relationship between the Gulf Coast and Southeast is intuitive (Fig. 4B). These two areas were not divided by physical barriers and shared similar climates and vegetation (Wolfe, 1985) allowing migration and dispersal between them. Florida connected to the mainland continent during the Miocene when the Gulf Trough filled in with sediment shed from the Appalachian Mountains, allowing dispersal with and from the Gulf Coast (Randazzo and Jones, 1997). Consistent vegetation in the Gulf Coast and Southeast regions may have inhibited allopatric speciation. Ancestral species that occupied the coastal regions did not speciate as frequently as species that migrated to the fragmented habitats of the cooler and drier Great Plains and Southwest regions. The Gulf Coast and Southeast areas are separated from the Great Plains and Southwest by a climatic gradient (sensu Retallack, 2007) as discussed above. Dispersal between all four regions most likely occurred before the global climate began to cool and vegetation shifted from woodland to grassland in the Great Plains. During the Middle Miocene, when distinct climatic regimes were in place (Wolfe, 1985), separating the four regions, dispersal was rare, occurring only for species tracking a browsing habitat and seeking refuge from the Great Plains in the moist, woodland coastal regions. The divergence of the four regions located ancestrally on the geodispersal tree supports the early dispersal among the areas and restricted dispersal later (Fig. 4B).

42 Comparison and Synthesis The vicariance and geodispersal trees are largely congruent with one another. The primary difference between the two trees is the location of the Southeast region. On the geodispersal tree, the Southeast is more closely related to the Gulf Coast than it is in the vicariance tree (Fig. 4). The Gulf Coast and Southeast had similar climatic regimes and woodland vegetation allowing almost continuous dispersal between them whereas the western areas (Great Plains and Southwest) had more arid climates (Axelrod, 1985; Wolfe, 1985; Thomasson et al., 1990; Retallack, 2007) restricting dispersal to and from the coastal areas (Webb et. al., 1995). The location of the Southeast on the vicariance tree separates it from the Gulf Coast (Fig. 4). This separation is a result of pre-Miocene fluctuations in sea level and the presence of the Gulf Trough possibly causing vicariant speciation between the Southeast and other regions before the Miocene. Dispersal occurred during the Miocene when the Gulf Trough was filled in with sediment and Florida was continuous with the mainland. This is represented by the location of the Southeast on the geodispersal tree. The location of the Southeast on both trees is consistent with geological data and together they give an accurate representation of Southeast’s relationship with the other three areas. The congruency between the trees indicates cyclical events (i.e., rise and fall of barriers) were the most significant factors driving the speciation and biogeographic evolution of the Equinae during the Miocene. Cyclical events that cause speciation on the time scale of this study are climatic change. Fluctuating climatic conditions resulting from global cooling and a rain shadow effect from the Cordilleran region created a

43 mixture of habitats in North America during the Miocene (Hulbert, 1993; Webb et. al., 1995). A variety of habitats that resulted from these climatic changes, supported a large diversity of Equinae species that were grazers, mixed feeders, and browsers (Webb et al., 1995). Conclusions Speciation of the Equinae clade was primarily driven by dispersal with a few episodes of vicariance. Speciation by geodispersal was a result of biogeographic shifts in response to environmental alteration caused by climate change. In North America during the Neogene, the fluctuating climate resulted in a variety of fragmented habitats as woodlands slowly shifted to open grasslands. The variety of habitats likely led to the diversity of the clade. Although this has been documented in previous studies (Hulbert, 1993; Webb et al., 1995), it is quantitatively presented here for the first time. The decline in diversity of the clade during the Pliocene has been attributed to climate change as well (Hulbert, 1993). Loss of woodland habitat from climate change may have resulted in the demise of several browsing species during early stages of global cooling (Webb et al., 1995). The first major extinction interval within the clade, effecting hypsodont horses, occurred during the driest time of the Neogene and the second occurred during a return to moist conditions similar to those seen in the Clarendonian (Axelrod, 1985; Leopold and Denton, 1987, Hulbert, 1993). During the second extinction interval, species exhibiting extreme hypsodonty were affected (Hulbert, 1993). A drop in diversity has also been attributed to increasing grasslands with lower productivity (MacFadden, 1998) due to a shift from C3-based savannas to C4-based grasslands

44 (Cerling, 1992; Cerling, et. al., 1993; Wang et.al., 1994). In addition, as grasslands spread, vegetation became more consistent and may have led to a decline in opportunites for allopatric speciation. The LPBA analysis presented here on a mammalian fauna from the Neogene is consistent with previous studies of Equinae evolution and North American geology. Phylogenetic biogeographic studies can be used on terrestrial taxa that have a well constrained phylogeny and abundant fossil record. Such studies may provide additional insight into the mechanisms driving the evolution of a clade with respect to the climate and geology of the distributional area. Dispersal and migration patterns can be more accurately reconstructed with such statistical methods as LBPA than with qualitative analysis.

45 References

Alroy, J., 2003. A quantitative North American mammalian timesale. www.nceas.ucsb.edu/~alroy/TimeSclae.html Axelrod, D.I., 1985. Rise of the grassland biome, Central North America. The Botanical Review 51 (2), 163-201. Barron, E.J., 1973. Late Miocene-early Pliocene paleotemperatures for California from marine diatom evidence. Palaeogeography, Palaeoclimatology, Palaeoecology 14 (4), 277-291. Cerling, T.E. 1992. Development of grasslands and savannas in East Africa during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology (Global and Planetary Change Section) 97, 241-247. Cerling, T.E., Wang, T., Quade, J., 1993. Expansion of C4 ecosystems as an indicator of global ecological change in the late Miocene. Nature 361, 344-345. Cole, M.R., Armentrout, J.M., 1979. Neogene paleogeography of the western United States. Pacific Section Society of Economic Paleontologist and Mineralogist Pacific Coast Paleogeography Symposium 3, 297-323. Effinger, W.L., 1934. The geology of Rocky Mountain National Park. US Department of National Park Service Field Division of Education, Berkeley, CA. Fitch, W.M., 1971. Toward defining the course of evolution. Minimum changes for a specific tree topology. Systematic Zoology 20, 406-416. Fortelius, M., 1985. Ungulate cheek teeth: developmental, functional, and evolutionary interrelations. Acta Zoologica Fennic 180, 1-76. Frazier, W.J., Schwimmer, D.R., 1987. Regional stratigraphy of North America. Plenum Press, New York, NY, 719 pp. Gradstein, F., Ogg, J., Smith, A., 2004. A Geologic Time Scale 2004. Cambridge University Press, Cambridge, England, 589 pp. Hembree, D.I., 2006. Amphisbaenian paleobiogeography; evidence of vicariance and geodispersal patterns. Palaeogeography, Palaeoclimatology, Palaeoecology 235(4), 340-354.

46 Hillis, D.M., Huelsenbeck, J.P., 1992. Signal, noise, and reliability in molecular phylogenetic analyses. Journal of Heredity 83, 189-195. Hulbert, Jr., R.C., 1984. Paleoecology and population dynamics of the Earl Miocene (Hemingfordian) horse Parahippus leonensis from the Thomas Farm Site, Florida. Journal of Vertebrate Paleontology 4, 547-558. Hulbert, Jr., R.C., 1987. Late Neogene Neohipparion (Mammalia, Equidae) from the Gulf Coastal Plain of Florida and Texas. Journal of Paleontology 61, 809-830. Hulbert, Jr., R.C., 1993. Taxonomic evolution in North American Neogene horses (Subfamily Equinae): the rise and fall of an adaptive radiation. Paleobiology 19 (2), 216-234. Hulbert, Jr., R.C., MacFadden, B.J., 1991. Morphological transformation and cladogenesis at the base of the adaptive radiation of Miocene hypsodont horses. American Museum Novitiates 3000, 1-61. Janis, C.M., 1984. The use of fossil ungulate communities as indicators of climate and Environment. In: Brenchley, P.J. (Ed.), Fossils and Climate. John Wiley and Sons, Chichester, England, pp. 85-104 Janis, C.M., 1988. An estimation of tooth volume and hypsodonty indices in ungulate mammals, and the correlation of theses factors with dietary preferences. Memoires Museum National d’Historie Naturelle Serie C 53, 367-387. Janis, C.M., 1989. A climatic explanation for patterns of evolutionary diversity in ungulate mammals. Paleontology 32, 463-481. Kelly, T.S., 1995. New Miocene horses from the Caliente Formation, Cuyama Valley Badlands, California. Natural History Museum of Los Angeles County, Contributions in Science 455, 1-33. Kelly, T.S., 1998. New Middle Miocene equid crania from California and their implications for the phylogeny of the Equini. Natural History Museum of Los Angeles County, Contributions in Science 473, 1-43. Klassen, G.J., Mooi, R.D., Locke, A., 1991. Consistency indices and random data. Systematic Zoology 40 (4), 446-457. Kominz, M.A., Miller, K.G., Browning, J.V., 1998. Long-term and short-term global Cenozoic sea-level estimates. Geology 26 (4), 311-314.

47 Kowalevsky, W. 1874. Monographie der battung Anthracotherium Cuvier und Versuch einer nturlichen classification der Fossilen Huftheire. Palaeontographica 22, 131346. Leopold, E.B., Denton, M.F., 1987. Comparative age of grassland and steppe east and west of the northern Rocky Mountains. Annals of the Missouri Botanical Garden 74, 841-867. Lewis, A.R., Marchant, D.R., Ashworth, A.C., Hemming, S.R., Machlus, M.L., 2007. Major middle Miocene global climate change: evidence from East Antarctica and the Transantarctic Mountains. Geological Society of America Bulletin 119(11), 1449-1461. Lieberman, B.S., 1997. Early Cambrian paleogeography and tectonic history: a biogeographic approach. Geology 25 (11), 1039-1042. Lieberman, B.S., 2000. Paleobiogeography. Kluwer Academic/Plenum Publishers, New York, 208 pp. Lieberman, B.S., Eldredge, N., 1996. Trilobite biogeography in the Middle Devonian: geological processes and analytical methods. Paleobiology 22 (1), 66-79. Lindsay, E.H., Opdyke, N.D., Johnson, N.M., 1979. Dispersal of the horse Equus in the Late Cenozoic. Acta Geologica Academiae Scientiarum Hungaricae, Tomus 22 (1-4), 75-80. Lindsay, E.H., Opdyke, N.D., Johnson, N.M., 1984. Blancan-Hemphillian land mammal ages and Late Cenozoic mammal dispersal events. Annual Reviews Earth Planetary Sciences 12, 445-488.

MacFadden, B.J., 1984. Systematics and phylogeny of Hipparion, Neohipparion, Nannippus, and Cormohipparion (Mammalia, Equidae) from the Miocene and Pliocene of the New World. Bulletin of the American Museum of Natural History 179, 1-196. MacFadden, B.J. 1992., Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge University Press, Cambridge, England, 369 pp. MacFadden, B.J. 1998., Equidae. In: Janis, C.M., Scott, K.M., Jacobs, L.L. (Eds.), Evolution of Tertiary Mammals of North America Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals. Cambridge University Press, Cambridge, England, pp. 537-559.

48 MacFadden, B.J., Hulbert, Jr., R.C., 1988. Explosive speciation at the base of the adaptive radiation of Miocene grazing horses. Nature (London) 336, 466-468. Marsh, O.C. 1879., Polydactyle horses, recent and extinct. American Journal of Science 17, 499-505. Mayr, E., 1942. Systematics and the Origin of Species. Dover Press, New York. 334 pp. Mayr, E. 1982. The Growth of Biological Thought. Harvard University Press, Cambridge, MA. 721 pp. Matthew, W.D., 1926. The evolution of the horse: a record and its interpretation. Quaternary Review of Biology 1, 139-185. Opdyke, N.D., 1995. Mammalian migration and climate over the last seven million years. In Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle. L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 109-114. Partridge, T.C., Bond, G.C., Hartnady, C.J.H., deMenocal, P.B., Ruddiman, W.F., 1995. Climatic Effects of Late Neogene Tectonism and Volcansim. In Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle. L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 8-23. Prado, J.L., Alberdi, M.T., 1996. A cladistic analysis of the horses of the tribe Equini. Palaeontology 39 (3), 663-680. Prothero, D.R., 1998. The chronological, climatic, and paleogeographic background to North American mammalian evolution. In: Janis, C.M., Scott, K.M., Jacobs, L.L. (Eds.), Evolution of Tertiary Mammals of North America Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals. Cambridge University Press, Cambridge, England, pp. 9-36. Randazzo, A.F., Jones. D.S., 1997. Geology of Florida. University Press of Florida, Gainsville, Florida, 327 pp. Renders, E., 1984. The gait of Hipparion sp. From fossil footprints in Laetoli, Tanzania. Nature 308, 179-181. Retallack, G.J., 1983. Late Eocene and Oligocene paleosols from Badlands National Park, South Dakota. The Geological Society of America Special Paper 193, 1-82.

49 Retallack, G.J., 1997. Neogene Expansion of the North American Prairie: Palaios 12, 380-390. Retallack, G.J., 2007. Cenozoic paleoclimate on land in North America. The Journal of Geology 115, 271-294. Rocchi, S., Di Vincenzo, G., LeMasurier, W.E., 2006. Oligocene to Holocene erosion and glacial history in Marie Byrd Land, West Antarctica, inferred from exhumation of the Dorrel Rock intrusive complex and from volcano morphologies. Geological Society of America Bulletin 118, 991–1005. Scotese, C.R., 1998. PALEOMAP Animations. PALEOMAP Project, University of Texas, Arlington. Sanderson, M.J., Donoghue, M.J., 1989. Patterns of variation in levels of homoplasy. Evolution 43 (8), 1781-1795. Shotwell, J.A., 1961. Late Tertiary biogeography of horses in the Northern Great Basin. Journal of Paleontology 35 (1), 203-217. Simpson, G.G., 1951. Horses: The Story of the Horse Family in the Modern World and through Sixty Million Years of History. Oxford University Press, Oxford, England, 247 pp. Stebbins, G.L. 1981. Coevolution of grasses and herbivores. Annals of the Missouri Botanical Garden 68, 75-86. Stigall, A.L., 2008. Integrating GIS and phylogenetic biogeography to assess specieslevel biogeographic patterns: A case study of Late Devonian faunal dynamics. In: Upchurch, P., McGowan, A., Slater, C. (Eds.), Palaeogeography and Palaeobiogeography: Biodiversity in Space and Time. CRC Press, expected publication March, 2008. Stigall, A.L., Lieberman, B.S., 2006. Quantitative palaeobiogeography: GIS, phylogenetic biogeographical analysis, and conservation insights. Journal of Biogeography 33, 2051-2060. Stigall Rode, A.L., Lieberman, B.S., 2005. Using environmental niche modeling to study the Late Devonian biodiversity crisis. In: Over, D.J., Morrow, J.R., Wignall, P.B. (Eds.), Understanding Late Devonian and Permian-Triassic Biotic and Climatic Events: Towards an Integrated Approach. Elsevier, Amsterdam, pp. 93127.

50 Stirton, R.A., 1940. Phylogeny of North American Equidae. University of California Publication. Bulletin of the Department of Geological Sciences 25, 165-198. Stirton, R.A., 1947. Observations on evolutionary rates in hypsodonty. Evolution 1, 3241. Stromberg, C.A.E., 2006. Evolution of hypsodonty in equids: Testing a hypothesis of adaptation. Paleobiology 32 (2), 236-258. Swofford, D.L., 2002. PAUP* 4.0. Sinauer Associates, Sunderland, Massachusetts. Thomasson, J.R., Voorhies, M.R., 1990. Grasslands and grazers. In: Briggs, D.E.G., Crowther, P.R. (Eds.), Palaeobiology: A Synthesis. Blackwell Scientific, Oxford, England, pp 84-87. Thomasson, J.R., Zakrzewski, R.J., Lagarry, H.E., Mergen, D.E., 1990. A late Miocene (late early Hemphillian) biota from northwestern Kansas. National Geographic Research 6, 231-244. Tiffney, B.H., Niklas, K.J., 1990. Continental area, dispersion, latitudinal distribution and topographic variety: a test of correlation with terrestrial plant diversity. In: Ross, R.M., Allmon, W.D. (Eds.), Causes of Evolution. University of Chicago Press, Chicago, IL, pp. 23-65. Trimble, D.E., 1980. The geological story of the Great Plains. Geological Survey Bulletin 1493, 55 pp. Valentine, J.W., Moores, E.M., 1970. Plate tectonic regulation of faunal diversity and sea level: a model. Nature 228, 657-659. Valentine, J.W., Moores, E.M., 1972. Global tectonics and the fossil record. Journal of Geology 80(2), 167-184. Van Valen, L,. 1964. Age in two fossil hors populations. Acta Zoologica 45, 93-106. Voorhies, M.R., 1969. Taphonomy and population dynamics of an early Pliocene vertebrate fauna, Knox County, Nebraska. Contributions to Geology, University of Wyoming, Special Paper 1, 1-69. Wallace, A.R., 1855. On the law which has regulated the introduction of new species. Annals and Magazine of Natural History, 2nd Series 16, 184-196.

51 Wang, Y, Cerling, T.E., MacFadden, B.J., 1994. Fossil horses and carbon isotopes: new evidence for Cenozoic dietary, habitat, and ecosystem changes in North America. Palaeogeography, Palaeoclimatology, Palaeoecology 107, 269-280. Webb, S.D., 1977. A history of the savanna vertebrates in the New World; Part I, North America. Annual Review of Ecology and Systematics 8, 355-380. Webb, S.D., 1983. The rise and fall of the late Miocene ungulate fauna in North America. In: Nitecki, M.H. (Ed.), Coevolution. University of Chicago Press, Chicago, Illinois, pp. 267-306. Webb, S.D., 1984. Ten million years of mammal extinctions in North America. In: Martin, P.S., Klein, R.G. (Eds.), Quaternary Extinctions: A Prehistoric Revolution. University of Arizona Press, Tucson, Arizona, pp.189-210. Webb, S.D., Hulbert, Jr., R.C., 1986. Systematics and evolution of Psuedhipparion (Mammalia, Equidae) from the late Neogene of the Gulf Coastal Plain and the Great Plains. In: Flanagan, K.M., Lillegraven, J.A. (Eds.), Vertebrates, Phylogeny, and Philosophy. Contributions to Geology, University of Wyoming, Special Paper 3, pp.237-272, Webb, S.D., Hulbert, Jr., R.C., Lambert, W.D., 1995. Climatic implications of largeherbivore distributions in the Miocene of North America. In: Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle, L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 91-108. Wolfe, J.A., 1985. Distribution of major vegetation types during the Tertiary. Geophysical Monograph 32, 357-375. Woodburne, M.O., 1996. Reappraisal of the Cormohipparion from the Valentine Formation, Nebraska. American Museum of Novitiates 3163, 56 pp. Woodruff, R., Savin, S.M., Douglas, R.G., 1981. Miocene stable isotope record: a detailed deep Pacific Ocean study and its paleoclimatic implications. Science 212, 665-668. Zachos, J.C., Pegani, M., Stone, L., Thomas, E., Billups, K., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present: Science 292, 686–693. Zubakov, V.A., Borzenkova, I.I., 1990. Global Palaeoclimate of the Late Cenozoic. Elsevier, Amsterdam., 456 pp.

52 CHAPTER 3: DISTRIBUTION OF FOSSIL HORSES IN THE GREAT PLAINS DURING THE MIOCENE AND PLIOCENE: AN ECOLOGICAL NICHE MODELING APPROACH

Abstract Geographic distributions of Miocene species in the Equinae clade are predicted using ecological niche modeling (ENM). Species inhabiting the Great Plains region of North America are examined as a case study area. The Equinae underwent a dramatic radiation as climate changed from warm and humid in the middle Miocene to cooler and more arid conditions during the late Miocene. Here I analyze the predicted distribution of individual species in relation to this climate change through ENM using the GARP (Genetic Algorithm using Rule-set Prediction) modeling system. This method predicts the geographic extent of a species’ fundamental niche based on environmental variables coupled with known species occurrence points and provides a means to quantify a species’ geographic range. Specifically, distributional patterns, habitat tracking, and species survival are examined in two time slices that span from the Mid-Miocene (Barstovian) Climatic Optimum into the early Pliocene (Blancan). Patchy distributions are more common in the middle Miocene when speciation rates are high. During the late Miocene, when speciation rates are lower, continuous ranges are more common. Equid species track their preferred habitat within the Great Plains region as well as regionally throughout North America. Species with larger predicted ranges survive during the initial cooling event but as climate continues to deteriorate in the late Miocene, range size is

53 irrelevant to survival and extinction rates increase. This is the first use of ENM and GARP in the continental fossil record.

Introduction The Equinae clade underwent a major radiation during the Miocene from one species, Parahippus leonensis, to 70 species, reaching its highest diversity during the Middle Miocene (Clarendonian) with 13 genera (MacFadden, 1992; Hulbert, 1993). The diversification of Equinae contains a variety of dental and muzzle morphologies, as well as a diverse range of body sizes and limb proportions (MacFadden, 1992). MacFadden (1992) and Webb et al. (1995) connect the morphological diversity to niche partitioning due to overlapping ranges. The radiation of this clade occurred in two pulses which have been attributed as adaptive responses to climate and vegetation change during the Miocene (MacFadden and Hulbert, 1988; Hulbert, 1993). The first radiation pulse occurred at approximately 18 Ma among the basal members of the clade. The second and larger radiation occurred between 15 and 12 Ma with the emergence of hypsodonty in equids (Hulbert, 1993). This event coincides with the first major cooling event of the Miocene (Zachos et al., 2001). Associated vegetation changes during the Miocene have been documented by paleoflora studies and stable isotope analyses of tooth enamel and paleosols (for review, see Jacobs et al., 1999). As the climate changed during the Miocene, the vegetation shifted from predominantly forest to a mosaic of woodland savanna and riparian forests that supported browsing, grazing and mixed feeding horses (Webb, 1983). This diversity peak, however, did not last. Equid diversity began to

54 decline during the late Miocene, and by the middle of the Pliocene only three genera were extant (Webb, 1984). Competition with other grazers (e.g., artiodactyls, rodents) was previously inferred to have caused the decline of the clade (Simpson, 1953; Stanley, 1974; Webb, 1969, 1984), but now it is attributed to the continuing climatic deterioration (MacFadden, 1992; Webb et al., 1995). Although the diversification of the Equinae has been hypothesized to have resulted from climate change, induced habitat fragmentation, and ecological specialization, the changing distribution of individual species has not been quantitatively mapped or analyzed previously. Most paleobiogeographic studies of equids have focused on large scale patterns, such as migration patterns from North America to the Old World (e.g., MacFadden 1992). Other paleobiogeographic studies have grouped equids with other Miocene mammalian clades to demonstrate general patterns, such as retreat to the Gulf Coast region when the climate became cool and arid in northern areas of North America during the late Miocene (e.g., Webb 1987; Webb et al., 1995). A more focused study examining the distribution of individual Equinae species can provide a framework in which to analyze habitat fragmentation and speciation. Since the radiation is hypothesized to have resulted from climate change, an integrated assessment of the ecology and biogeography is necessary to fully understand evolutionary patterns in the clade. Shotwell (1961) recognized this in his study on the biogeography of horses in the northern Great Basin. Shotwell (1961) observed a change in species composition that coincided with vegetational change and concluded that the shift in the species resulted from immigration of equid species native to other regions that were adapted to the new

55 vegetative regime into the Great Basin . However, there have been several advances in the phylogenetic relationships of the clade and their morphologies since Shotwell’s (1961) study which provides a more robust framework for new analyses. Furthermore, numerous recent studies have investigated the environmental and climatic conditions of the Great Plains during the Miocene. These studies include analyses of vegetation type (eg. Fox & Koch, 2003; Strömberg, 2004; Thomasson, 2005), paleosol composition (eg. Retallack, 1997,2007), and climate proxies (eg. Woodruff et al., 1981; Zachos et al., 2001) that provide a rich source of environmental information previously unavailable for equinid biogeographic analyses. Here I reconstruct the geographic ranges for individual species of Miocene horses based on environmental variables to assess how changing climate and shifting habitats affected evolutionary patterns in the Equinae. In order to study the distribution of horses on a fine geographic scale, I employ ecological niche modeling (ENM). A species ecological niche is defined as the set of environmental tolerances and limits in multidimensional space that defines where a species is potentially able to maintain populations (Grinnell, 1917; Hutchinson, 1957). This is also known as a species fundamental niche because it contains all areas in which a species could potentially live based on the fundamental parameters needed by the species to survive. Species, however, do not fill their entire fundamental niche. Biotic intereactions result in a restricted or smaller niche called a species realized niche (Lomolino et al., 2006). Modeling a species realized niche unfortunately is not possible from the paleontological recored. Determining the ecological or fundamental niche of a taxon, however is possible and is essential in determining its potential distribution

56 (Peterson, 2001). Ecological niche modeling uses a set of environmental variables to estimate the distribution of a species based on the set of environmental conditions of locations where a species is known to occur. The fossil record of equids is denselysampled and abundant locality information provides a robust record of where each species lived in North America (MacFadden, 1992). Direct mapping of species ranges from known occurrence points may underestimate a species’ actual geographic range due to the inherent biases of the paleontological record (Kidwell and Flessa, 1996; Stigall Rode, 2005). More accurate ranges can be constructed by using ENM to model species ranges based on known occurrence points and environmental parameters from the sedimentary record. Ecological niche modeling is widely employed in modern biological studies to predict the distribution of species for conservation purposes (e.g., Peterson et al., 2002; Wiley et al., 2003; Nunes et al., 2007). There are several niche modeling programs available (e.g. BIOCLIM, GARP), and all are successful in predicting the geographic range of taxa (Peterson, 2001). This study employs the GARP (Genetic Algorithm using Rule-set Prediction) modeling system developed by R. Scachetti-Pereira (www.lifemapper.org/desktopgarp). GARP is a learning-based analytical package that predicts the fundamental niche of a species using environmental coverage data in concert with a set of known species occurrence points (Stockwell and Peters, 1999). GARP has been successfully employed with numerous modern mammalian studies investigating ecological and environmental questions (e.g. Lim et al., 2002; Illoldi-Rangel et al., 2004). It has also been successfully employed in the fossil record of marine invertebrates (Stigall

57 Rode and Lieberman, 2005). This study represents the first application of ENM and GARP, however, to fossil vertebrates. In this study I examine the distributional patterns of individual species to better understand the rise and fall of the Equinae in relation to environmental and climatic change. Ecological niches are modeled and geographic ranges predicted in order to study how species’ distributions shifted through time as a result of climatic and vegetative changes. Specifically, I will test if habitat fragmentation led to the diversification of the clade and if distributional patterns and range size affected the survivorship of individual species.

Methods Geographic and Stratigraphic Intervals Geographic Extent The distributions of species belonging to the Equinae clade were predicted for two successive time slices during the Miocene and Early Pliocene in the Great Plains region of North America (Table 1). The study area incorporated regions of the High Plains, as defined by Trimble (1980), which includes northern Texas, western Oklahoma, western Kansas, Nebraska, eastern Colorado, southeastern Wyoming, and southern South Dakota (Fig. 5). Although equid species inhabited regions of North America outside the study area, the Great Plains region was chosen for the focus of this study due to the abundant amount of published data on both the distribution of equid fossil material and the environmental setting of the region during the Miocene and Pliocene. To facilitate

58 analysis of environmental data, the study region was divided into 1° grid boxes (Fig. 5), which is standard procedure for GARP analyses because modern environmental data is typically presented in this format (e.g., Stockwell and Peterson, 2002). Environmental parameter data was collected for as many one degree grid boxes as possible from literature sources (Table 2). If a grid box had more than one data point for an environmental parameter, the average value of all data points representing the parameter was reported for the grid box.

Table 1. Species modeled in the middle (middle Miocene) and late (late Miocene to early Pliocene) time slices. Middle Time Slice Calippus martini Calippus placidus Calippus regulus Cormohipparion occidentale Cormohipparion quinni Hipparion tehonense Merychippus coloradensis Merychippus insignis Merychippus republicanus Neohipparion affine Neohipparion trampasense Pliohippus mirabilis Pliohippus pernix Protohippus perditus Protohippus supremus Pseudhipparion gratum Pseudhipparion hessei Pseudhipparion retrusum

Late Time Slice Astrohippus ansae Astrohippus stockii Cormohipparion occidentale Dinohippus interpolatus Dinohippus leidyanus Equus simplicidens Nannipus aztecus Nannipus lenticularis Nannipus peninsulatus Neohipparion eurystyle Neohipparion leptode Pliohippus nobilis Protohippus gidleyi

59 Table 2. Environmental data references by variable. Percent C4 vegetation (stable isotope data based on tooth enamel† or paleosols*) Fox and Fisher, 2004† Fox and Koch, 2003* Passey et al., 2002† Wang et al., 1994† Clouthier, 1994† Mean Annual Precipitation Damuth et al., 2002 Retallack, 2007 Retallack, unpublished data Mollic Epipedon Retallack, 1997 Retallack, unpublished data Vegetation Axelrod, 1985 Gabel et al., 1998 MacGinitie, 1962 Strömberg, 2004 Thomasson, 1980 Thomasson, 1983 Thomasson, 1990 Thomasson, 1991 Thomasson, 2005 Wheeler, 1977 Faunal Assemblages Markwick, 2007

60

Figure 5. A) Study area with 1° x 1° grid boxes overlain. B-C) Distribution of environmental data (red circles) and species occurrence data (blue triangles) for the middle time slice (B) and late time slice (C). Base map shows paleoelevation in meters, modified from Markwick (2007).

61 Climatic, Temporal and Stratigraphic Framework Data was collected for three time slices in order to analyze the distribution of species through the climatic changes of the Miocene and Pliocene (only two time slices were used in the final analysis). The time slices (Table 1; Fig. 1) were determined based on reversals and slope of the temperature in the climate curve of Zachos et al. (2001), which is the Cenozoic climate curve most widely employed in the literature. This climate curve is a compilation of global deep-sea oxygen and carbon isotope records of benthic foraminifera from over 40 Deep Sea Drilling Project and Ocean Drilling Program sites culled from the literature. The first time slice spans 8.5 million years from the Arikareean through the early Barstovian. Temperatures rose about 2°C during this interval until the Mid-Miocene Climatic Optimum was reached at approximately 17-18 Ma (Zachos et al., 2001). Temperature estimates from stable oxygen isotopes of benthic foraminifera in the Tasman Sea indicate a peak at about 13°C during this interval (Cooke et al., 2008). Mean annual precipitation was approximately 900 mm (Retallack, 2007). Sediments weathering from the mountains uplifting in the Cordilleran region were deposited across the northern part of the Great Plains region through eastward flowing streams, forming the Arikaree Group, a mixture of volcaniclastics, eolian, fluvial and lacustrine deposits (Condon, 2005). The second time slice comprises 5.5 million years and spans the late Barstovian age through the end of the Clarendonian age. This time slice begins after the MidMiocene Climatic Optimum, as temperatures began to decline dramatically. Falling

62 temperatures fluctuated with an overall drop from 13°C to about 7.5-9.5°C (Cooke et al., 2008). This interval of global cooling was mediated by the formation of permanent ice sheets on Antarctica (Woodruff et al., 1981; Zachos et al., 2001; Rocchi et al., 2006; Lewis et al., 2007). The development in the Late Cenozoic of a rainshadow from the uplifting Cordilleran region in concert with the cooling temperatures resulted in increased aridity in the Great Plains during the middle Miocene (Zubakov and Borzenkova, 1990; Ward and Carter, 1999). Mean annual precipitation fluctuated between 1000 mm and 500 mm during this interval (Retallack, 2007). Eastward flowing streams continued to deposit sediment on the Great Plains forming the Ogallala Group, an eastward sloping wedge of coarse fluvial sediments that eroded from the Laramie and Front Ranges (Condon, 2005). The Ogallala Group sediments include braided stream, alluvial fan, low relief alluvial plain, and lacustrine deposits (Goodwin and Diffendal, 1982; Scott, 1982; Swinehart and Diffendal, 1989; Flanagan and Montagne, 1993). The third time slice is 6.5 million years in duration and includes the Hemphillian through the Blancan ages, spanning the Miocene-Pliocene boundary. At the beginning of this time slice in the Miocene, temperatures stabilized at approximately 8°C in the early Hemphillian and then continued to decline reaching a minimum of 4.5°C before rising back to 8°C by then end of the Miocene (Zachos et al., 2001; Cooke et al., 2008). This cooling was associated with aridity during the Miocene as mean annual precipitation dropped to 250 mm (Retallack, 2007). During the Pliocene, however, mean annual precipitation increased to approximately 1050 mm as temperatures continued to cool (Chapin and Kelley, 1997; Cooke et al., 2008). Deposition of the Ogallala Group

63 continued during first half (late Miocene portion) of this time slice. Erosion of the western mountain ranges slowed during the Pliocene; as deposition slowed, an unconformity formed above the Ogallala Group (Condon, 2005). Furthermore, the Great Plains region began to slowly uplift (Morrison, 1987). As the region rose, sediments in the western Great Plains were stripped away and either redeposited on top of the Ogallala Group or removed completely; however, sediments accumulated in Nebraska during the Pliocene due to its northeastward slope at the time (Steven et al., 1997).

Species Occurrence Information Species occurrence data were collected from the primary literature as well as online databases (Miocene Mammal Mapping Project [MIOMAP] (Carrasco et al., 2005) and the Paleobiology Database [PBDB]). Species name, occurrence (latitude and longitude), and stratigraphic position were recorded for each species of Equinae (Appendix C). I honored the reidentifications of several specimens in the PBDB record performed by Alroy (2002, 2007) of the Paleobiology Database. The occurrence data was split into the three times slices described above. Although species occurrence data was collected for all species considered valid in recent phylogenetic hypotheses, such as Hulbert (1993), Kelly (1995, 1998), Prado et al. (1996), and Woodburne (1996) (Fig. 1), species with fewer than five spatially distinct occurrences in the study region per time slice were excluded from the analysis. This cutoff number has been determined from modeling experiments to be the minimum data required to produce robust GARP analyses (Peterson and Cohoon, 1999; Stockwell and Peterson, 2002).

64

Environmental Data A variety of environmental factors (e.g., temperature, climate, vegetation, resource availability) may determine the ecological niche of a horse species. In order to model niches of extinct species, environmental factors are estimated from sedimentary variables collected from the sedimentary record (Stigall and Lieberman, 2005). Five environmental parameters representing vegetation, temperature, and precipitation were included in this study. Each of these parameters can be determined from the sedimentary record, either through fossils, or directly from the sedimentary rock. The combination of these variables creates a robust data set of environmental factors that influence the distribution of horses. The use of five environmental variables is consistent with standard GARP methodology as analyses have been successful with as few as four and as many as 19 environmental factors (e.g., Anderson et al., 2002; Feria and Peterson, 2002; Peterson and Cohoon, 1999). Although covariation among these environmental variables exists (e.g. vegetation and C4% or MAP and crocodile presence), GARP is not sensitive to covariation among environmental variables because it is a Bayesian-based system that produces accurate results for a wide range of domains, such as numerical function optimization, adaptive control system design, and artificial intelligence tasks (Stockwell and Peters, 1999). Classical and parametric statistics, on the other hand, are sensitive to covariation within data and, therefore, are not applicable for this study. The five environmental parameters are discussed individually below. All data is presented in Tables 3 and 4.

65

Stable Carbon Isotopes During the Cenozoic, dominant vegetation shifted from leafy shrubs and trees (C3 plants) to grasslands (C4 plants). This shift in vegetation created a mosaic of food sources for equid taxa during the Miocene, resulting in a diverse range of morphological feeding adaptations in the Equinae clade (MacFadden, 1992; Webb et al., 1995). The distribution of a species’ food resource is primary factor determining its ecological niche and range (Fox & Fisher, 2004; Lomolino et al., 2006). Carbon isotope composition (δ13C) can be used as a proxy for vegetation type (C3 or C4) in the Great Plains. C3 and C4 plants have different photosynthetic pathways (Calvin cycle and Hatch-Slack cycle, respectively) used for fixing atmospheric CO2 (Cerling and Quade, 1993). Each pathway fractionates carbon isotopes to a different degree, producing non-overlapping carbon isotope compositions. Modern C3 plants exhibit a δ13C range of -22‰ to -35‰ with an average of – 27‰ (O’Leary, 1988; Tieszen and Boutton, 1989), while modern C4 plants exhibit a range of -10‰ to -14‰ with an average of -13‰ (O’Leary, 1988; Tieszen and Boutton, 1989). A third pathway, crassulacean acid metabolism (CAM), results in carbon isotope compositions intermediate of the other two pathways, but it is primarily utilized by succulent plants in arid conditions (Cerling and Quade, 1993) and uncommon in the study area. Stable carbon isotope data included in this study were assembled from published literature sources that analyzed δ13C from either paleosols or tooth enamel of equids and proboscideans (Table 2). Paleosol stable carbon isotopes studies included in this analysis

66 applied an enrichment value of +14-17‰ to all values according to Cerling et al. (1989, 1991). Enamel studies applied an enrichment factor of +14‰ to all values according to Cerling and Harris (1999). δ13C values also account for the 1.5‰ decrease of atmospheric CO2 that has occurred since the onset of human fossil fuel burning (Friedli et al., 1986). Raw stable carbon isotope data were converted into % C4 vegetation based on Fox and Koch (2003) and Passey et al. (2002). Percent C4 vegetation was used as an index of the vegetative composition. Low C4 percentages are interpreted as predominantly leafy vegetation preferred by browsers, high percentages are interpreted as predominantly grassy vegetation preferred by grazers and intermediate percentages represent vegetation preferred by mixed feeders.

Mean Annual Precipitation Rainfall directly influenced the vegetation available to equid species for feeding and represents a fundamental parameter of a species’ ecological niche (e.g., Anderson et al., 2002; Illoldi-Rangel et al., 2004). Mean annual precipitation (MAP) values determined from paleosols, ungulate tooth size, and vegetation were compiled for analysis (Table 2). The depth of the Bk horizon in paleosols can be utilized to estimate MAP using the equation: P = 137.24 + 6.45D – 0.013D2 where D is depth in cm (Jenny, 1941; Retallack, 1994, 2005). MAP data estimated from ungulate tooth size within a community using “Per-species mean hypsodonty” (PMH), a measure of MAP developed by Damuth et al. (2002), was also included in this study. PMH is the average hypsodonty of the ungulate fauna divided by the number of all mammalian species present in a

67 community (Janis et al., 2004). Lastly, MAP ranges interpreted from plant assemblages (Axelrod, 1985; Thommason, 1980) were utilized in this study.

Mollic Horizon Soil horizons can provide information about precipitation, climate, and vegetation cover. As discussed above, these factors influence the distribution of species. Modern soils supporting grassy vegetation have a mollic epipedon, a surface layer consisting of dark organic clayey soil about 2-5 mm thick (Retallack, 1997). In paleosols, mollic epipedons are recognized by dark thin clayey rinds to small rounded soil peds along with fine root traces. In addition, fossilized mollic epipedons are nutrient-rich and often contain carbonate or easily weathered minerals. Retallack (1997, pers communication 2007) divided paleosols containing calcareous nodules from the Great Plains during the Miocene into three categories. The first category, mollic, contained all paleosols that adhered to the above criteria. The second category, near mollic, was assigned to paleosols that had surface horizons with “a structure of subangular to rounded peds some 5-10 mm in size, along with abundant fine root traces and darker color than associated horizons” (Retallack, 1997). Near mollic epipedons are found under bunch grasslands of woodlands or under desert grasslands (Retallack, 1997). The third category, non-mollic, was assigned to all other paleosols included in the study. This third group consisted primarily of paleosols similar to soils of deserts and woodlands (Retallack, 1997). The vegetation cover interpreted from the three categories of mollic epipedons were utilized and coded 1, 2, and 3, respectively.

68

Vegetation The fourth environmental variable included in this analysis is ecosystem type as determined from paleobotanical studies (Table 2). Although an extensive collection of paleobotanical occurrences and taxonomic descriptions exist in the literature, only studies that included a paleoenvironmental description were included in the data set for this analysis. These environmental descriptions were coded and divided into four categories: 1) Woodland [e.g. “deciduous valley and riparian forests with scattered grasslands” (Axelrod 1985)] 2) Savanna or subtropical grassland with surrounding wooded areas [e.g. “subtropical grassland with associated mesic and woody components” (Thomasson, 2005)] 3) Savanna or subtropical grassland [e.g. “grassland savanna” (Gabel et al., 1998)] 4) Dominantly grassland/Steppe [e.g. “grassland, shrubs, with limited trees” (Thomasson, 1990)]

Vertebrate Assemblages In the fossil record, crocodiles have traditionally been used as paleotemperature proxies (Lyell, 1830; Owen, 1850). Based on ecological analysis of modern crocodilians, temperature is considered to be the most influential factor determining the distribution of modern crocodiles (Woodburne, 1959; Martin, 1984; Markwick, 1996). The dataset

69 used in this analysis is derived from the comprehensive work of Markwick (1996, 2007). Markwick (1996) compiled a database of vertebrate assemblages from around the world and used the distribution of crocodiles as a paleotemperature proxy from the Cretaceous through the Neogene. Markwick (1996) includes crocodiles that belong to the “crown group” (Alligatoridae, Crocodylidae, and Gavialidae families). The climatic tolerance of the modern American alligator, Alligator mississippiensis, was used as the minimum climate tolerance of extinct crocodiles. Alligator mississippiensis can tolerate an average temperature range of 25-35° C. Because crocodiles are well documented in the fossil record and Markwick (1996, 2007) includes noncrocodillian vertebrate sites as a control group, crocodilian absences in his database are considered true absences. This study includes 95 assemblages from Markwick (2007) that fall within the study area. For this study, crocodilian presence and absences were coded 1 and 0, respectively.

Table 3. Environmental data for each grid box in the middle time slice. Mollic MAP*(mm) Epipedon Vegetation Long. Lat. % C4 3 (1) -102.5 43.5 266.17 (1) 3 (1) 3 (11) -101.5 43.5 -100.5 43.5 356.31 (17) 2.9 (17) 3 (9) -99.5 43.5 -97.5 42.5 13 (1) 1590.65 (1) 2.5 (2) -98.5 42.5 16 (3) 819.07 (4) 2 (3) 3 (7) -99.5 42.5 18.4 (6) 519.57 (15) 2.1 (13) 3 (12) -100.5 42.5 10.6 (5) 825 (1) 2.8 (4) -101.5 42.5 15 (1) -102.5 42.5 16 (1) 410.34 (9) 1 (8) -103.5 42.5 13.5 (3)

Crocodile Presence 0 (1) 0 (1) 1 (2) 1 (1) 0 (3) 1 (1) 0 (1) 1 (2)

70 Table 3: continued -104.5 -103.5 -102.5 -101.5 -98.5 -100.5 -103.5 -104.5 -100.5 -99.5 -99.5 -99.5 -100.5 -101.5 -100.5 -100.5 -101.5

41.5 41.5 41.5 41.5 40.5 40.5 40.5 40.5 39.5 39.5 37.5 36.5 36.5 36.5 35.5 34.5 33.5

18.5 (2) 28 (1) 16 (1) 0 (1) 23 (1) 21 (1) 17.3 (3) 18 (1) 12 (1) 5 (1) 1 (1) 29 (2)

325.86 (1) 479.59 (3) 1888.09 (1) 1143.92 (1) 633.87 (1) 402.61 (2) 266.53 (1) 825 (1) 760 (1) -

2 (2) 2.5 (2) -

2 (1) 1 (1) 2 (1) 3 (1) -

0 (1) 0 (1) 0 (1) 0 (1) 1 (1) 1 (1) 1 (2) 0 (1) -

* Mean Annual Precipitation Values in parathenses indicated the number of data points for the environmental variable in the specified grid box. Environmental data is averaged per grid box. Original values are described below: Mollic Epipedon: 1 = mollic, 2 = near-mollic, 3 = non-mollic Vegetation: 1= woodland, 2 = savanna with surrounding woodland, 3 = savanna, 4 = grassland/steppe Crocodile Presence: 0 = absence, 1 = presence

Table 4. Environmental data for each grid box in the late time slice. Mollic Long. Lat. % C4 MAP*(mm) Epipedon Vegetation 59 (1) 323.53 (1) -98.5 43.5 55 (1) 661.38 (2) -97.5 42.5 15 (1) 486.91 (2) -98.5 42.5 37 (3) 379.16 (5) -99.5 42.5 1.8 (5) 0 (1) 393.11 (1) -100.5 42.5 2 (1) -

Crocodile Presence 0 (1) 0 (1) -

71 Table 4: continued -101.5 -103.5 -103.5 -102.5 -101.5 -100.5 -99.5 -98.5 -97.5 -100.5 -102.5 -101.5 -100.5 -99.5 -97.5 -99.5 -100.5 -100.5 -99.5 -99.5 -100.5 -101.5 -102.5 -101.5 -100.5 -99.5 -100.5 -101.5 -102.5 -102.5 -101.5 -100.5 -99.5

42.5 42.5 41.5 41.5 41.5 41.5 41.5 41.5 41.5 40.5 40.5 39.5 39.5 39.5 39.5 38.5 38.5 37.5 37.5 36.5 36.5 36.5 35.5 35.5 35.5 34.5 34.5 34.5 34.5 33.5 33.5 33.5 33.5

58 (1) 12 (3) 26 (2) 27 (5) 19 (2) 15 (1) 21 (1) 69 (2) 12 (1) 38 (2) 8 (1) 4 (1) 9.5 (2) 37 (2) 21 (1) 0 (1) 43 (3) 20 (1) 11 (1) 21.5 (2) -

533.87 (1) 335.94 (6) 349.42 (23) 339.2 (5) 275.54 (1) 820.2 (1) 520.47 (1) 646.52 (1) 429.28 (17) 365.76 (27) 181.26 (1) 252.52 (2) 356.51 (27) 503.01 (42) 148.43 (1) -

Refer to Table 3 for explanation

2.2 (6) 2.5 (22) 2.3 (4) 1.6 (16) 2.3 (27) 3 (2) 2.9 (27) 2.5 (41) -

2.7 (3) 2 (1) 4 (1) 2 (2) 2 (1) 3 (1) -

0 (5) 0 (2) 0 (3) 1 (1) 0 (1) 0 (3) 0 (1) 0 (1) 0 (2) 0 (1) 1 (3) 0 (1) 1 (1)

72 Creation of Environmental Layers For analysis of environmental data, the study region was divided into 1° grid boxes using latitude and longitude coordinates. This method is equivalent to that employed in modern GARP analyses (e.g. Stockwell and Peterson, 2002; Wiley et al., 2003; Illoldi-Rangel et al., 2004). Environmental parameters derived from the literature, as discussed above, were assigned to the appropriate grid box. If multiple data points occurred in one grid box, the values were averaged to account for environmental variability. This method of intermediate coding has been successful with GARP analysis and is an effective method of representing environmental variability (Stigall Rode and Lieberman, 2005). Original data is included in Appendix D. Although data was initially collected for an early Miocene time slice, niche modeling could not be performed for this time slice due to insufficient environmental data. Percent C4 and vegetation data only covered two grid boxes, making interpolation (discussed below) impossible for these environmental variables. The other three environmental variables from the early time slice covered more than two boxes but did not cover the same range as the other two time slices, making comparisons between time slices impossible. Lastly, occurrence data for species in the first time slice did not overlap spatially with the environmental coverage areas; therefore, the minimum number of five discrete occurrence points for each species was not met. While no biogeographic models could be constructed for the early time slice, this interval is included in discussions below. Consequently, niche models are produced for two time slices, representing the middle Miocene, the middle time slice, and late Miocene/early Pliocene, the late time slice.

73 Environmental data points for the middle and late time slices were imported into ArcGIS 9.2 (ESRI Inc, 2006). An interpolated surface was created for each environmental variable using the inverse distance weight procedure. Four data points were used to create each interpolated surface with a power of 3 and an output cell size of 0.1 (8 x 11 km). Interpolation was based on four data points because this was the largest number of data points appropriate for interpolation that were available from all environmental data sets. The interpolated environmental area for the middle time slice and late time slice covered from 104°W 44°N to 98°W 34°N and 104°W 44°N to 97°W 33°N, respectively. An example of an interpolated environmental coverage is shown in Figure 6.

Distribution Modeling A genetic algorithm approach was chosen to model the distribution of Equinae species. Genetic algorithms have been successfully used in previous niche modeling analyses of paleontological data (Stigall Rode and Lieberman, 2005) because genetic algorithms are effective for data sets with unequal sampling and poorly-structured domains (Stockwell and Peterson, 2002). Other statistical methods such as multiple regression and logistic regression, assume multivariate normality and true absence data. Because absence in paleontological data does not necessarily represent true absence and multivariate normality is unlikely with paleontological data, these methods are not suitable here. Genetic algorithms apply a series of rules in an iterative, evolving manner to the data set until maximum significance is reached (Stockwell and Peters, 1999). The

74

Figure 6. Examples of environmental variable interpolations. A) Stable isotope interpolation representing the percentage of C4 vegetation in the late time slice. B) Crocodile presence/absence interpolation for the middle time slice, 0 = absence, 1 = presence. See Figure 5 for base map explanation.

75

genetic algorithm program employed in this study, GARP (Genetic Algorithm using Rule-set Prediction), was specifically designed to predict species ranges based on their fundamental niche as estimated from environmental variables (Peterson and Vieglas, 2001). Another strength of the GARP modeling system is it was originally designed to accommodate for data from museum collections, in particular GARP is able to accommodate for non-uniformly distributed, sparse, or patchy data (Peterson and Cohoon, 1999; Stockwell and Peters, 1999). Furthermore, co-variance between environmental variables does not negatively impact the model results (Stockwell and Peters, 1999). All species distribution modeling was performed using DesktopGARP 1.1.4 (www.nhm.ku.edu/desktopgarp). GARP is composed of eight programs that include data preparation, model development, model application and model communication (Stockwell and Peters, 1999). The GARP system divides the data in half to create two groups, the test group and the training group. A rule (e.g. logit, envelope) is randomly selected and applied to the training set. The accuracy of the rule is assessed using 1250 points from the test data set and 1250 points randomly re-sampled from the area as a whole. The rule is then modified (mutated) and tested again. If accuracy increases, the modified rule is incorporated in the model, if not, it is excluded. GARP creates separate rule sets for each region within the study area, rather than forcing a global rule across the data. This results in higher accuracy and precision in resulting models than global rule methods (Stockwell and Peters, 1999; Stockwell and Peterson, 2002). The algorithm continues until further modification of the rules no longer results in improved accuracy or

76 the maximum number of iterations set by the operator is reached (Stockwell and Noble, 1992; Stockwell and Peters, 1999). Prior to performing the modeling analysis, the statistical significance of each environmental variable was tested using a jackknifing procedure. This was done by selecting all combinations of rules and selected layers for the GARP analysis (Stigall Rode and Lieberman, 2005). The five most abundant species (Cormohipparion occidentale, Neohipparion affine, Pliohippus pernix, Protohippus supremus, Pseudhipparion gratum) were used from the middle time slice in the jackknifing procedure. The contribution of each environmental variable to model error, measured by omission and commission, was analyzed using a multiple linear regression analysis in Minitab 14 (Minitab Inc., 2003). An environmental variable was inferred to increase error in the model if it was significantly correlated with either omission or commission. A multiple linear regression analysis was conducted for the five species in the middle time slice together as well as each individual species in the middle time slice. Although each environmental variable is significantly correlated to error with at least one species; no environmental variable contributed significant error with all species. Therefore, all variables were considered valid as environmental predictors and were included in the niche modeling analysis. Niche modeling was performed individually for each species in each time slice. All rules were selected to be used, as well as all environmental layers and 500 replicate models were run for each species with the convergence interval set at 0.01. Training points were set to 50% as discussed above. The best subset selection was utilized so that

77 the ten best models were chosen with an omission threshold of 10% and a commission threshold of 50%. Range predictions were output as ASCII grids and the ten best models were imported into ArcGIS 9.2. The ASCII grids were converted into raster files and weight-summed to derive the final range prediction maps (Figure 7). The geographic area occupied by each species was quantified for biogeographic analysis (Table 5).

Biogeographic Analyses Examination of Distributional Patterns and Habitat Tracking Habitat Fragmentation The relative prevalence of patchy ranges, ranges in which a species’ distribution includes multiple discrete areas of occurrence, versus widespread continuous ranges was analyzed. Habitat fragmentation has been hypothesized to contribute to the radiation of numerous clades (e.g., birds: Mayr, 1942). If geographic patchiness does increase speciation rate, I should expect to see a higher number of patches in the predicted ranges of species in the middle time slice when speciation rates were higher, than those in the late time slice, when the clade was in decline. The number of discrete populations or patches occupied was counted for each species in each time slice (Table 5). The extent of a population or patch was defined by a contained area that did not have a continuous connection with a second population. The number of populations per species for each time slice was statistically analyzed using a Two-Sample T-Test (Table 6). Range Shift and Habitat Tracking

78 Initial examination of range models indicated an apparent southernward shift of species between the time slices. This apparent southward shift of species was analyzed statistically. The study area for each species was divided in half along the 39°N latitudinal in the middle time slice and the 38.5°N latitudinal in the late time slice. For both time slices, the percent area occupied by each species was calculated using ArcGIS (Table 5). A two sample T-Test was applied to determine whether species in the late time slice occupied a statistically larger portion of the southern region of the Great Plains than species of the middle time slice, indicating a range shift to the south (Table 7). Only one species, Cormohipparion occidentale, was extant in both time slices. To determine whether the shifting distribution of C. occidentale from one time slice to another was a function of habitat tracking, the niche model for the middle time slice was projected onto the late time slice environmental layers (Peterson et al., 2001). If the resulting distributional pattern matches the original predicted distribution of C. occidentale for the late time slice, then C. occidentale tracked its preferred habitat from the middle time slice to the late time slice (i.e., niche conservatism). If the distributional patterns do not have a high degree of overlap, C. occidentale did not occupy the same niche in both time slices, and therefore the species would be interpreted to have altered its fundamental niche through time (i.e., niche evolution). To determine whether the distributions were equivalent, the area overlap was measured in ArcGIS and compared to the area not shared as a percentage.

79

Table 5. Geographic ranges predicted for species in the middle and late time slices from GARP Modeling.

80 Examination of Species Survival versus Range Size Whether a general relationship between species longevity and predicted distribution area occurs was also assessed through a regression analysis (Table 8). Specifically, the general pattern that species with larger range sizes live longer was tested. The longevity of each species was determined from the literature as illustrated in the stratocladogram in Fig. 1.The relationship between species survival across North American Land Mammal Age (NALMA) divisions and the geographic extent of a species’ distributional range was also examined. Statistical analyses were performed for each Land Mammal Age division within the temporal extent of this study (Barstovian/Clarendonian, Clarendonian/Hemphillian, and Hemphillian/Blancan). Survival across the boundary was compared to the size of the species’ predicted range. The area of each species range was determined within ArcGIS by calculating the sum of the areas in which seven or more of the ten best models predict occurrence (Table 5). Previous methods have summed three of the five best (Lim et al., 2002), six of the ten best (e.g., Stigall Rode and Lieberman, 2005), and all of the ten best (Peterson et al., 2002; Nunes et al., 2007), so our approach is more conservative. Raw area counts were converted into percentage of total model areas for the time slice because the extent of the niche modeling area is different between time slices (Table 5). A nonparametric statistical method, Kruskal-Wallis, was used to analyze the relationship between survival and area because the data are not normally distributed even after log, square root, and arcsine transformations were applied (Tables 9, 10, 11).

81 Results and Discussion Ranges were predicted for 18 species from the middle time slice and 13 species from the late time slice (Table 1). Predicted ranges for the middle and late time slice are included in Appendix E.

Habitat Fragmentation During the middle time slice, predicted species ranges were divided into more populations or patches than during the late time slice (Two-Sample T-Test, p=1.15x10-4) (Table 6). The relative abundance of patchy habitats in the middle time slice correlates with the mid Miocene interval of rapid cooling. Speciation was high during the middle time slice and the Equinae clade reached its highest diversity at this time (MacFadden, 1992; Hulbert 1993). Fragmentation of habitats led to patchy distributions. This in turn led to niche partitioning and speciation via vicariance, giving rise to the diverse group of mixed feeders, browsers and grazers that inhabited the mosaic of vegetation in the Great Plains (Webb et al., 1995). The more continuous species ranges of the late time slice may be the result of spreading grasslands. Environmental coverages of the middle time slice show an area of low precipitation, high percentages of C4 plants, and an absence of crocodiles that spans across the central part of the Great Plains (Fig. 6b). In several predicted ranges for the middle time slice, this area is not occupied (Fig. 7a). The environmental coverages for the late time slice indicate a return to more wet conditions in this area and a more uniform environmental distribution throughout the study area. Predicted species ranges in the late

82 time slice include this area resulting in more continuous ranges from the northern to southern part of the study area (Fig. 7b). Chapin and Kelley (1997) reported increased precipitation in the Pliocene based on the establishment of drainage systems, the erosion of Mesozoic and Cenozoic sediments, the opening of previously closed basins and stable isotope compositions of paleosol carbonates in arid lands. Approximately 6-7 Ma, grasslands expanded into wetter climatic regions (Retallack, 1997). As grasslands spread throughout the Great Plains in the Late Miocene and Pliocene, habitats became more homogeneous (Axelrod, 1985; Webb et al., 1995). The available range for species adapted for open grassland and steppe habitats increased, creating large continuous distributions. Continuous ranges may have reduced speciation (Hulbert, 1993) within the clade due to lack of vicariant barriers, a pattern previously observed in Devonian marine taxa (Stigall, 2008). While the diversification of the Equinae clade has been attributed to habitat fragmentation and niche partitioning (MacFadden, 1992), its decline has been attributed to the inability of species to adapt to climatic deteriorations during the Late Miocene and Pliocene (Webb, 1983; MacFadden, 1992). However, lower speciation rates due to the increase in continuous habitat availability following the spread of grasslands, may have also been influential in the decline of the clade. Hulbert (1993) observed high extinction rates in the late Miocene coupled with low speciation rates that eventually reached zero.

83 Table 6. Two-Sample T-Test comparing number of discrete populations per time slice. Source Sample Size (N) Mean Standard Deviation SE Mean Middle 18 2.389 0.698 0.16 Late 13 1.308 0.630 0.17 T statistic = -4.50 p = 1.154x10-4 Degrees of Freedom = 24

Habitat Tracking As temperatures decreased during the Miocene and the climate became more arid, several species adapted to wooded savannas rather than open grasslands retreated to warmer and wetter regions of North America, specifically the southern Great Plains and Gulf Coast regions (i.e., Nannippus aztecus and Nannippus peninsulatus; Fig. 7c,d) (Webb et al., 1995). Based on data from carbonate nodules, Retallack (2007) determined that a climatic gradient from warm and humid in the coastal regions to cool and arid in the northern Great Plains region existed. Species of Equinae in the late time slice of this study occupied larger ranges south of 38.5°N latitudinal, than species of the middle time slice below 39°N latitudinal (Two Sample T Test P = 0.009) (Table 7). This southernward shift indicates that species may have tracked their preferred habitat to the south as climate changed more drastically in the northern regions of North America. Closer examination of morphological differences due to diet type between the species will result would further test this hypothesis.

84

Figure 7. GARP predicted species distribution maps for (A) Pseudhipparion gratum in the middle time slice and (B) Nannippus lenticularis, (C) Nannippus aztecus, and (D) Pseudhipparion peninsulatus in the late time slice. The range prediction key indicates how many of the ten best subset maps predict species to occur at a location. See Figure 5 for base map explanation.

85 Table 7. Two-Sample T-Test comparing the area of a species’ geographic range in the Southern Great Plains per time slice. Source Sample Size (N) Mean Standard Deviation SE Mean Middle 18 20.80 20.40 4.8 Late 13 35.69 7.62 2.1 T statistic = -2.84 p= 0.009 Degrees of Freedom = 23

By the Hemphillian, the southwestern region of North America was semi-arid and was dominated by shrubland vegetation (Axelrod, 1985). Many ungulates retreated from this region into the Great Plains (Webb et al., 1995). This included five species that were modeled in the late time slice: Dinohippus leidyanus, Dinohippus interpolatus, Equus simplicidens, Astrohippus ansae, and Astrohippus stockii (Maguire and Stigall, In review). Maguire and Stigall (In Press) determined that speciation of these five taxa was a result of geodispersal across the Rocky Mountains from the Southwest to the Great Plains. Predicted distributional ranges of the five species are similar and occur predominantly on the western edge of the Great Plains region (Fig. 8). During the Neogene, the uplift of the Rocky Mountains was interrupted by intervals of tectonic quiescence (Condon, 2005). The distributional patterns predicted from niche modeling supports the conclusion of Maguire and Stigall (In Press) that speciation of these five species was a result of a cyclical geodispersal process as habitat tracking occurred across the Rocky Mountains.

86

Figure 8. GARP predicted distribution maps for (A) Astrohippus ansae and (B) Dinohippus interpolatus in the late time slice. See Figure 5 for the base map explanation and Figure 7 for range prediction explanation.

87

As previously mentioned one species, Cormohipparion occidentale, was extant during both the middle and late time slices. The species predicted distributions are presented in Figure 9a and 9c for the middle and late time slice, respectively. Any GARP model, for example the middle time slice GARP model, is based on the relationship between a species and its preferred habitat. This same relationship can be used to predict a species distribution for another time slice, for example the late time slice. The percent overlap of the original prediction by the middle GARP model and the new prediction for the late time slice indicates how the relationship between the species and its preferred habitat remained the same between both time slices. The consistency of this relationship can be referred to as habitat tracking. Projection of the GARP model for the middle time slice onto the environmental layers of the late time slice produced a distribution that covered 48.85% of the area originally predicted for the late time slice (Fig. 9b,c). This percentage of overlap suggests that Cormohipparion occidentale tracked its preferred habitat from the middle time slice into the late time slice. In addition, projection of the late time slice GARP model onto the middle time slice environmental layers produced a distribution that was 52.21% similar to the original distribution for the middle time slice (Fig. 9a,d). The predicted distributional maps show during the middle time slice, the species’ niche does not occupy the central region of the study area (Fig. 9a). In the late time slice, however, the predicted range does cover this central area, indicating that C. occidentale spread through this region as it tracked its habitat (Fig. 9c). Unlike other genera of Equinae, Cormohipparion migrated to the Old World during the Miocene along with the genus Hipparion (Skinner & MacFadden, 1977; MacFadden, 1992).

88

Figure 9. GARP prediction maps for Cormohipparion occidentale. A) Predicted distribution for the middle time slice. B) Predicted distribution when the middle time slice model is projected onto the late time slice. C) Predicted distribution for the late time slice. D) Predicted distribution when the late time slice model is projected onto the middle time slice. See Figure 5 for base map explanation and Figure 7 for range prediction explanation.

89

Cormohippairon also was one of the last genera remaining in North America at the end of the Miocene (C. emsliei survived in the coastal regions through the Blancan). The combination of its longevity and large range may be a result of its ability to track its preferred habitat.

Range Size vs. Survival A positive relationship between geographic range size and species longevity occurs in many clades (Stanley, 1970; Vrba, 1987; Rode and Lieberman, 2004; Hendricks et al., 2008). This relationship has not been quantitatively assessed in prior analyses of equid biogeography; however, statistical analysis of this relationship is possible based on niche models constructed in this study. No significant relationship between predicted range size and longevity was recovered when all species ranges modeled from both time slices were combined in a single regression analysis (Table 8, p = 0.670). However, when the size of species’ geographic range was compared with survival or extinction across specific boundaries between NALMA divisions, significant relationships were uncovered. The NALMA divisions (Alroy, 2003) are based on first and last appearance data of all mammals in North America and are neither dependent on “immigrant first appearance datum” nor heavily dependent on geochronology data. Species living in the Barstovian that survived into the Clarendonian had statistically larger ranges than species that became extinct by the end of the Barstovian (KruskalWallis Test, p = 0.013) (Table 9). Clarendonian species that survived into the Hemphillian did not have significantly larger ranges than species that became extinct

90 (Kruskal-Wallis Test, p = 0.183) (Table 10). Furthermore, Hemphillian species that survived into the Blancan did not have significantly larger ranges (Kruskal-Wallis Test, p = 0.571) (Table 11). This last result may be a function of small sample population as only 11 species in this study were extant during the Hemphillian.

Table 8. Linear Regression Analysis of species longevity and the area of a species’ geographic range. Predictor Coefficient SE Coefficient T P Constant 2.84 0.81 3.51 0.001 Area 0.01 0.03 0.43 0.670 Longevity = 2.84 + 0.01(Area) S = 1.66 R-Sq = 0.6%

Table 9. Kruskal-Wallis Test comparing the area of a species’ geographic range versus species survival across the Barstovian/Clarendonian Boundary. Source Same Size (N) Median Average Rank Z Value Survival 9 27.93 11.1 2.49 Extinct 7 13.70 5.1 -2.49 H = 6.19 p= 0.013 Degrees of Freedom = 1

91 Table 10. Kruskal-Wallis Test comparing the area of a species’ geographic range versus species survival across the Clarendonian/Hemphillian Boundary. Source Same Size (N) Median Average Rank Z Value Survival 10 30.77 15.4 1.33 Extinct 15 24.28 11.4 -1.33 H = 1.77 p = 0.183 Degrees of Freedom = 1

Table 11. Kruskal-Wallis Test for comparing the area of a species’ geographic range versus species survival across the Hemphillian/Blancan Boundary. Source Same Size (N) Median Average Rank Z Value Survival 4 42.87 6.8 0.57 Extinct 7 32.91 5.6 -0.57 H = 0.32 p = 0.571 Degrees of Freedom = 1

The relationship between survival from one NALMA to another and species range size may be a function of climate and vegetation change. In the Miocene, temperatures dropped quickly from 13°C to 7.5-9.5°C during the Barstovian (Zachos et al., 2001; Cooke et al., 2008). During this interval of climate change, vegetation cover was shifting and patchy. Under those conditions, the range size of individual species was important for survival into the Clarendonian. Species with larger ranges and broader ecological tolerances were better adapted to the changing environment. Those with smaller ranges and more restricted ecological tolerances could not adapt. During the late Miocene,

92 however, species range size was irrelevant to survival. Temperatures continued to drop to approximately 2.3°C during the Clarendonian and Hemphillian, accompanied by decreasing MAP that reached 500 mm (Zachos et al., 2001; Retallack, 2007; Cooke et al., 2008). Climatic deterioration became too severe even for those species with large ranges and broad ecological tolerances to survive. Precipitation increased in the Pliocene and grasslands spread into areas with more moisture. Only species that were adapted to the spreading grassland habitat exhibited large geographic ranges and survived into the Pliocene.

Regional Trends The Great Plains is analyzed as a case study for niche modeling. Equinae species, however, inhabited other regions of North America during the Miocene, and dispersal between these regions was frequent. The distributional patterns that resulted influenced the speciation of the clade (Maguire and Stigall, In Press). Here I briefly discuss how regional patterns and local (ecological) patterns are related in the Great Plains region. Pliohippus mirabilis had a patchy habitat in the Great Plains during the middle time slice (Fig. 10a) that covered 24.3% of the study area. Pliohippus mirabilis evolved into P. pernix through anagenetic speciation (Hulbert, 1993). The patchy pattern of P. mirabilis supports the interpretation that vicariance due to habitat fragmentation led to the speciation of P. pernix. Pliohippus pernix had a continous range throughout the Great Plains during the middle time slice that covered 43.4% of the study area (Fig. 10b). This broadly distributed and adapted species dispersed to the Gulf Coast in the middle time

93 slice (Maguire and Stigall, In Press). In the Great Plains P. pernix evolved into P. nobilis anagenetically (Hulbert, 1993). Pliohippis nobilis had a patchy predicted distribution in the Great Plains that covered 28% of the total area (Fig. 10c). Although it has a predominantly southern distribution in the Great Plains, this species remained in the Great Plains during the late Miocene and did not disperse to other regions of North America and became extinct by the Pliocene. The patchy habitat of P. nobilis may illustrate the lack of suitable habitat for the species in the Great Plains. Due to its inability to migrate to other regions of North America, for example the Gulf Coast, it became extinct in the early Hemphillian (Fig. 1). The combination of regional and local distribution patterns provides a more complete picture of the biogeography and evolution of Equinae during the Miocene than either does alone. Here, Pliohippus provides an example of how the local distribution pattern is consistent with the regional pattern. The five species previously discussed that migrated into the Great Plains from the southwest are another example of how the local pattern supports the regional pattern. Their western predicted distribution pattern in the Great Plains suggests they or their ancestors dispersed from the southwestern region of North America. Maguire and Stigall (In Review) concluded the same five species in the Great Plains speciated through geodispersal from their ancestors in the southwest.

94

Figure 10. GARP predicted species distribution maps for (A) P. mirabilis, and (B) P. pernix in the middle time slice and P. nobilis in the late time slice. See Figure 5 for base map explanation and Figure 7 for range prediction explanation.

95 Conclusions Equid species of the middle Miocene comprised a higher number of discrete populations than late Miocene-early Pliocene species. Diversification of the Equinae occurred just prior to the middle Miocene indicating speciation coincided with the distribution of patchy habitats. Habitat fragmentation resulted from changes in vegetation of the Great Plains as the climate began to deteriorate. Following dramatic cooling in the Barstovian, species with larger ranges preferentially survived compared to species with smaller geographic distributions. During the late Miocene, however, when temperatures were even cooler, and the climate more arid, species range size was irrelevant to survival. The dichotomy between these intervals may reflect differential response of species to rate of climatic deterioration (rapid vs. gradual) or that a climatic threshold had been passed following the Barstovian which affected specialists and generalists equally. Some species, such as Cormorohipparion occidentale, exhibited niche conservatism (habitat tracking) within the Great Plains as the climate deteriorated. Other species, such as Dinohippus interpolatus and Astrohippus ansae, tracked their preferred habitats from the southwestern region of North America to the Great Plains, while others, such as Pliohippus pernix, tracked their preferred habitats from the Great Plains to the Gulf Coast (Webb et al., 1995). Within the Great Plains region, distributional patterns show invasion of species from the southwest and an overall southward shift towards the Gulf Coast. Species ranges were more continuous during the late Miocene to early Pliocene than during the middle Miocene. More continuous ranges may have led to a decrease in

96 speciation rate of the clade due to lack of subpopulation isolation. Low speciation rate coupled with increased extinction rate from the deteriorating climate resulted in the decline of Equinae in North America. While Equus thrived on the Great Plains during the Pliocene and into the Pleistocene, other genera such as Cormohipparion and Pseudhipparion retreated to the coast, however, these species became extinct by the end of the Pliocene. Finally, niche modeling of horse species in this study has produced a quantitative, detailed framework in which to analyze further hypotheses about the relationship between morphology, ecology, and evolution. Niche modeling of species ranges in the Gulf Coast region would provide further insight into the final decline of the clade. In addition, matching morphological characteristics of individual species with the environmental parameters of their predicted niches would provide more detailed information about niche partitioning and habitat tracking during the Miocene. For example, examining the muzzle morphology of species in this study that showed significant migration southward versus those that did not, may demonstrate whether all species migrated south or only those not specialized in open grassland grazing. This study is the first quantitative analysis of ecological biogeography using ENM in a vertebrate fossil clade. Results of this study support ENM as an effective tool for modeling the ranges of fossil vertebrate species and which allows analysis of biogeographic patterns within a hypothesis testing framework.

97 References Alroy, J., 2002. Synonymies and reidentifications of North American fossil mammals. The Paleobiology Database, http://paleodb.org/ Alroy, J., 2003. A quantitative North American mammalian timescale. www.nceas.ucsb.edu/~alroy/TimeScale.html Alroy, J., 2007. Synonymies and reidentifications of North American fossil vertebrates and so forth. The Paleobiology Database, http://paleodb.org/ Anderson, R.P., Peterson, A.T., Gómez-Laverde, M., 2002. Using niche-based GIS modeling to test geographic predictions of competitive exclusion and competitive release in South American pocket mice. OIKOS 98, 3-16. Axelrod, D.I., 1985. Rise of the grassland biome, Central North America. The Botanical Review 51 (2), 163-201. Carrasco, M.A., Kraatz, B.P., Davis, E.B., Barnosky, A.D., 2005. Miocene Mammal Mapping Project (MIOMAP). University of California Museum of Paleontology, http://www.ucmp.berkeley.edu/miomap/ Cerling, T.E., Quade, J., 1993. Stable carbon and oxygen isotopes in soil carbonates. In: Swart, P.K., Lohmann, K.C., McKenzie, J., Savin, S. (Eds.), Climate Change in Continental Isotopic Records. Geophysical Monograph, vol. 78. American Geophysical Union, Washington, DC, pp. 217-231. Cerling, T.E., Harris, J.M., 1999. Carbon isotope fractionation between diet and bioapatite in ungulate mammals and implications for ecological and paleoecological studies. Oecologia 120, 347-363. Cerling, T.E., Quade, J., Wang, Y., Bowman, J.R., 1989. Carbon isotopes in soils and palaeosols as ecology and palaeoecology indicators. Nature 341, 138-139. Cerling, T.E., Solomon, D.K., Quade, J., Bowman, J.R., 1991. On the isotopic composition of carbon in soil carbon dioxide. Geochimica et Cosmochimica Acta 55, 3403-3405. Chapin, C.E., and Kelley, S.A., 1997. The Rocky Mountain erosion surface in the Front Range of Colorado. In: Bolyard, D.W., Sonnenberg, S.A. (Eds.), Geologic history of the Colorado Front Range. Rocky Mountian Association of Geologists, Denver, CO, pp. 101-113.

98 Clouthier, S.G., 1994. Carbon and nitrogen isotopic evidence for tertiary grassland distributions and the evolution of hypsodonty in North American Great Plains horses (32 Ma to recent). Master’s Thesis. Michigan State University. Condon, S.M., 2005. Geological studies of the Platte River, south-central Nebraska and adjacent areas; geologic maps, subsurface study, and geologic history. US Geolgocical Survey Professional Paper 1706, Denver, CO, 63 pp. Cooke, P.J., Nelson, C.S., Crundwell, M.P., 2008. Miocene isotope zones, paleotemperatures, and carbon maxima events at intermediate water-depth, Site 593, Southwest Pacific. New Zealand Journal of Geology & Geophysics 51, 1-22. Damuth, J.D., Fortelius, M., Andrews, P., Badgley, C., Hadley, E.A., Hixon, S., Janis, C.M., Madden, R.H., Reed, K., Smith, J.M., Theodor, J.M., van Dam, J.A., Van Valkenburgh, B., Werdelin, L., 2002. Reconstruction mean annual precipitation based on mammalian dental morphology and local species richness. Journal of Paleontology 22 (suppl. 3), 48A. ESRI Inc., 2006. ArcGIS 9.2 Release. Redlands, CA. Feria, T.P., Peterson, A.T., 2002. Prediction of bird community composition based on point-occurrence data and inferential algorithms: a aluable tool in biodiversity assessments. Diversity and Distributions 8, 49-56. Flanagan, K.M., Montagne, J., 1993. Neogene stratigraphy and tectonics of Wyoming. In: Snoke, A.W., Stidtmann, J.R., Roberts, S.M. (Eds.), Geology of Wyoming.: Geological Survey of Wyoming Memoir 5, pp. 572-607. Fox, D.L., Koch, P.L., 2003. Tertiary history of C4 biomass in the Great Plains, USA. Geology 31 (9), 809-812. Fox, D.L., Fisher, D.C., 2004. Dietary recontruction of Miocene Gomphotherium (Mammalia, Probosciea) from the Great Plains region, USA, based on the carbon isotope composition of tusk and molar enamel. Palaeogeography, Palaeoclimatology, Palaeoecology 206, 311-335. Friedli, H., Lötshcer, H., Oeschger, H., Siegenthaler, U., Staufer, B., 1986. 13C/12C ration of atmospheric CO2 in the past two centuries. Nature 324, 237-238. Gabel, M.L., Backlund, D.C., Haffner, J., 1998. The Miocene macroflora of the northern Ogallala Group, northern Nebraska and southern South Dakota. Journal of Paleontology 72 (2), 388-397.

99 Goodwin, R.G., Diffendal, R.F., 1987. Paleohydrology of some Ogallala (Neogene) streams in the southern pandhandle of Nebraska. In: Ethridge, R.G., Flores, R.M., Harvey, M.D., Weaver, J.N. (Eds.), Recent developments in fluvial sedimentology. Society of Economic Paleontologists and Mineralogists Special Publication 39, pp. 149-157. Grinnell, J., 1917. Field tests of theories concerning distributional control. American naturalist 51, 115-128. Hendricks, J.R., Lieberman, B.S., Stigall, A.L., 2008. Using GIS to study the paleobiogeography of soft-bodied Cambrian arthropods. Palaeogeography, Palaeoclimatology, Palaeoecology, in press. Hulbert, Jr., R.C., 1993. Taxonomic evolution in North American Neogene horses (Subfamily Equinae): the rise and fall of an adaptive radiation. Paleobiology 19 (2), 216-234. Hutchinson, G.E., 1957. Concluding remarks. Cold Spring Harbor Symposium on Quaternary Biology 22, 415-427. Illoldi-Rangel, P., Sánchez-Cordero, V., 2004. Predicting distributions of Mexican mammals using ecological niche modeling. Journal of Mammalogy 85(4), 658662. Jacobs, B.R., Kinston, J.D., Jacobs, L.L., 1999. The origin of grass-dominated exosystems. Annals of the Missouri Botanical Garden 86 (2), 590-643. Janis, C.M., Damuth, J., Theodor, J.M., 2004. The species richness of Miocene browsers, and implications for habitat type and primary productivity in the North American grassland biome. Palaeogeography, Palaeoclimatology, Palaeoecology 207, 371398. Jenny, H.J., 1941. Factors of soil formation. McGraw-Hill, New York, 281 pp. Kidwell, S.M., Flessa, K.W., 1996. The quality of the fossil record: Populations, species and communities. Annual Review of Ecolog and Systematics 24, 433-464. Lim, B.K., Peterson, A.T., Engstrom, M.D., 2002. Robustness of ecological niche modeling algorithms for mammals in Guyana. Biodiversity and Conservation 11, 1237-1246. Lomolino, M.V., Riddle, B.R., Brown, J.H., 2006. Biogeography, 3rd Edition. Sinauer Associates, Sunderland, Massachusetts, 845 pp.

100 Lewis, A.R., Marchant, D.R., Ashworth, A.C., Hemming, S.R., Machlus, M.L., 2007. Major middle Miocene global climate change: evidence from East Antarctica and the Transantarctic Mountains. Geological Society of America Bulletin 119(11), 1449-1461. Lyell, C., 1830. Principles of Geology, Being an Attempt to Explain the Former Changes of the Eaarth’s Surface, by Reference to Causes Now in Operation Volume 1. John Murray, London, 511 pp. Kelly, T.S., 1995. New Miocene horses from the Caliente Formation, Cuyama Valley Badlands, California. Natural History Museum of Los Angeles County, Contributions in Science 455, 1-33. Kelly, T.S., 1998. New Middle Miocene equid crania from California and their implications for the phylogeny of the Equini. Natural History Museum of Los Angeles County, Contributions in Science 473, 1-43. MacFadden, B.J., 1984. Systematics and phylogeny of Hipparion, Neohipparion, Nannippus, and Cormohipparion (Mammalia, Equidae) from the Miocene and Pliocene of the New World. Bulletin of the American Museum of Natural History 179, 1-196. MacFadden, B.J., 1992. Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge University Press, Cambridge, England, 369 pp. MacFadden, B.J., Hulbert, Jr., R.C., 1988. Explosive speciation at the base of the adaptive radiation of Miocene grazing horses. Nature (London) 336, 466-468. MacGinitie, H.D., 1962. The Kilgore flora, a late Miocene flora from Northern Nebraska. University of California Publications in Geological Sciences 35, 67-158. Maguire, K.C., Stigall, A.L., In Press. Paleobiogeography of Miocene Equinae of North America: A phylogenetic biogeograpic analysis of the relative roles of climate, vicariance, and dispersal. Palaeogeography, Palaeoclimatology, Palaeoecology, 37 pp. Markwick, P.J., 1996. Late Cretaceous to Pleistocene climates: nature of the transition from a ‘hot-house’ to an ‘ice-house’ world. PhD University of Chicago, 1196 pp. Markwick, P.J., 2007. The palaeogeographic and palaeoclimatic significance of climate proxies for data-model comparisons. In: Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N. (Eds.), Deep-time Perspectives on Climate Change. The Micropalaeontological Society & The Geological Society of London, London, pp. 251-312.

101

Martin, J.E., 1984. A crocodilian from the Miocene (Hemingfordian) Sheep Creek Formation in northwestern Nebraska. Proceedings of the South Dakota Academy of Science 63, 48-55. Mayr, E., 1942. Systematics and the origin of species from the viewpoint of a zoologist. Columbia University Press, New York, 334 pp. Minitab Inc., 2003. Minitab Release 14. State College, Pennsylvania. Morrison, R.B., 1987. Long-term perspective: changing rates and types of Quaterary surficial processes: erosion-deposition-stability cylces. In: Grag, W.L. (Ed.), Geomorphic systems of North America: Geological Society of America, Centennial Special 2, 163-210. Nunes, M.F.C., Galetti, M., Marsden, S., Pereira, R.S., Peterson, A.T., 2007. Are largescale distributional shifts of the blue-winged macaw (Primolius maracana) related to climate change? Journal of Biogeography 34, 816-827. O’Leary, M.H., 1988. Carbon isotopes in photosynthesis. Bioscience 38, 328-336. Owen, R., 1850. On the fossil Crocodilia of England. The Edinburgh New Philosphical Journal 49, 248-250. Passey, B.H., Cerling, T.E., Perkins, M.E., Voorhies, M.R., Harris, J.M., Tucker, S.T., 2002. Environmental change in the Great Plains: An isotopic record from fossil horses. The Journal of Geology 110, 123-140. Peterson, A.T., 2001. Predicting species’ geographic distributions based on ecological niche modeling. The Condor 103, 599-605. Peterson, A.T., Cohoon, K.P., 1999. Sensitivity of distributional prediction algorithms to geographic data completeness. Ecological Modelling 117, 159-164. Peterson, A.T., Vieglais, D.A., 2001. Predicting species invasions using ecological niche modeling: new approaches from bioinformatics attack a pressing problem. BioScience 51, 363-371. Peterson, A.T., Sánchez-Cordero, V., Soberón, J., Bartley, J., Buddemeier, R.W., Navarro-Sigüenza, A.G., 2001. Effects of global climate change on geographic distributions of Mexican Cracidae. Ecological Modelling 144, 21-30. Peterson, A.T., Ball, L.G., Cohoon, K.P., 2002. Predicting distributions of Mexican birds using ecological niche modeling methods. Ibis 144, E27-E32.

102

Prado, J.L., Alberdi, M.T., 1996. A cladistic analysis of the horses of the tribe Equini. Palaeontology 39 (3), 663-680. Retallack, G.J., 1994. The environmental factor approach to the interpretation of paleosols. In: Luxmore, R.J. (Ed.), Factors of Soil Formation: A Fiftieth Anniversary Retrospective. SSA Special Publication 33. Social Science Society of America, Madison, WI, pp. 31-64. Retallack, G.J., 1997. Neogene expansion of the North American Prairie. Palaios 12, 380390. Retallack, G.J., 2005. Pedogenic carbonate proxies for amount and seasonality of precipitation in paleosols. Geology 33, 333-336. Retallack, G.J., 2007. Cenozoic paleoclimate on land in North Amirca. The Journal of Geology 115, 271-294. Rocchi, S., Di Vincenzo, G., LeMasurier, W.E., 2006. Oligocene to Holocene erosion and glacial history in Marie Byrd Land, West Antarctica, inferred from exhumation of the Dorrel Rock intrusive complex and from volcano morphologies. Geological Society of America Bulletin 118, 991–1005. Rode, A.L., Lieberman, B.S., 2004. Using GIS to unlock the interactions between biogeography, environment, and evolution in Middle and Late Devonian brachiopods and bivalves. Palaeogeography, Palaeoclimatology, Palaeoecology 211, 345-359. Scott, G.R., 1982. Paleovalley and geologic map of northeastern Colorado. US Geological Survey Miscellaneous Investigation Series Map I-378, 12 pp. Shotwell, J.A., 1961. Late Tertiary biogeography of horses in the Northern Great Basin. Journal of Paleontology 35 (1), 203-217. Simpson, G.G., 1953. The Major Features of Evolution. Columbia University Press, New York, NY, 434 pp. Skinner, M.F., MacFadden, B.J., 1977. Cormohipparion n. gen. (Mammalie, Equidae) from the North American Miocene (Barstovian-Clarendonian). Journal of Paleontology 51, 912-926. Stanley, S.M., 1974. Effects of competition on rates of evolution, with special reference to bivalve mollusks and mammals. Systematic Zoology 22 (4), 486-506.

103 Stanley, S.M., 1979. Macroevolution, pattern and process. W.H. Freeman and Company, San Francisco, CA, 332 pp. Steven, T.A., Evanoff, E., Yuhas, R.H., 1997. Middle and Late Cenozoic tectonic and geomorphic development of the Front Range of Colorado. In: Bolyard, E.W., Sonnenberg, S.A. (Eds.), Geologic history of the Colorado Front Range. Rocky Mountain Association of Geologists, Denver, CO, pp. 115-124. Stigall, A.L., 2008. Integrating GIS and phylogenetic biogeography to assess specieslevel biogeographic patterns: A case study of Late Devonian faunal dynamics. In: Upchurch, P., McGowan, A., Slater, C., (Eds.), Palaeogeography and Palaeobiogeography: Biodiversity in Space and Time. CRC Press, in press. Stigall Rode, A.L., 2005. The application of geographic information systems to paleobiogeography: Implications for the study of invasions and mass extinctions. In: Lieberman, B.S., Stigall Rode, A.L. (Eds.), Paleobiogeography: Generating New Insights into the Coevolution of the Earth and its Biota. The Paleontological Society Papers 11, 77-88. Stigall Rode, A.L., Lieberman, B.S., 2005. Using environmental niche modeling to study the Late Devonian biodiversity crisis. In: Over, D.J., Morrow, J.R., Wignall, P.B. (Eds.), Understanding Late Devonian and Permian-Triassic Biotic and Climatic Events: Towards an Integrated Approach. Developments in Paleontology and Stratigraphy. Elsevier, Amsterdam, pp. 93-127. Stockwell, D.R.B., Noble, I.R., 1992. Induction of sets of rules from animal distribution data: a robust and informative method of data analysis. Mathematical and computer Simulation 33, 385-390. Stockwell, D.R.B., Peters, D., 1999. The GARP modeling system: problems and solutions to automated spatial prediction. International Journal of Geographical Information Science 13 (2), 143-158. Stockwell, D.R.B., Peterson, A.T., 2002. Effects of sample size on accuracy of species distribution models. Ecological Modelling 148, 1-13. Stömberg, C.A., 2004. Using phytolith assemblages to reconstruct the origin and spread of grass-dominated habitats in the Great Plains of North America during the late Eocene to early Miocene. Palaeogeography, Palaeoclimatology, Palaeoecology 207, 239-275.

104 Swinehart, J.B., Diffendal, R.F., 1989. Geology of the pre-dune strata. In: Bleed, A.S., Flowerday, C.A. (Eds.), An atlas of the Sand Hills: Conservation and Survey Division, Institute of Agriculture and Natural Resources, University of NebraskaLincoln, Resource Atlas 5, pp. 29-42. Thomasson, J.R., 1980. Archaeoleersia nebraskensis gen. et sp. nov. (GramineaeOryzeae), a new fossil grass from the late Tertiary of Nebraska. American Journal of Botany 67, 876-882. Thomasson, J.R., 1983. Carex graceii sp. n., Cyperocarpus eliasii sp. n., Cyperocarpus terrestris sp. n., and Cyperocarpus pulcherrima sp. n. (Cyperaceae) from the Miocene of Nebraska. American Journal of Botany 70 (3), 435-449. Thomasson, J.R., 1990. Fossil plants from the late Miocene Ogallala Formation of central North America: possible paleoenvironmental and biostratigraphic significance. In: Gustavson, T.C. (Ed.), Geologic Framework and Regional Hydrology: Upper Cenozoic Blackwater Draw Ogallala Formations, Great Plains. Bureau of Economic Geology, The University of Texas, Austin, pp. 99-114. Thomasson, J.R., 1991. Sediment-borne “seeds” from Sand Creek, northwestern Kansas: taphonomic significance and paleoecological and paleoenvironmental implications. Thomasson, J.R., 2005. Berriochloa gabeli and Berriochloa huletti (Gramineae: Stipeae), two new grass species from the late Miocene Ash Hollow Formation of Nebraska and Kansas. Journal of Paleontology 79 (1), 185-199. Tieszen, L.L., Boutton, T.W., 1989. Stable carbon isotopes in terrestrial ecosystems research. In: Rundel, P.W., Ehleringer, J.R., Nagy, K.A. (Eds.), Stable Isotopes in Ecological Research. Springer-Verlag, New York, pp. 167-195. Trimble, D.E., 1980. The geologic story of the Great Plains. Geological Survey Bulletin 1493, 55 pp. Vrba, E.S., 1987. Ecology in relation to speciation rates: some case histories of MioceneRecent mammal clades. Evolutionary Ecology 1, 283-300. Wang, Y., Cerling, T.E., MacFadden, B.J., 1994. Fossil horses and carbon isotopes: new evidence for Cenozoic dietary, habitat, and ecosystem change in North America. Ward, P.A., III, Carter, B.J., 1999. Rates of stream incision in the middle part of the Arkansas River basin based on late Tertiary to mid-Pleistocene volcanic ash. Geomorphology 27, 205-228.

105 Webb, S.D., 1969. Extinction-origination equilibria in late Cenozoic land mammals of North America. Evolution 23, 688-702. Webb, S.D., 1983. The rise and fall of the Late Miocene ungulate fauna in North America. In: Nitecki, M.H. (Ed.), Coevolution. The University of Chicago Press, Chicago, IL, pp. 267-306. Webb, S.D., 1984. Ten million years of mammal extinctions in North America. In: Martin, P.S., Klein, R.G. (Eds.), Quaternary Extinctions: A Prehistoric Revolution. University of Arizona Press, Tucson, Arizona, pp.189-210. Webb, S.D., 1987. Community patterns in extinct terrestrial vertebrates. In: Gee, J.H.R., Giller, P.S. (Eds.), Organization of Communities Past and Present. Blackwell, Oxford, pp. 439-466. Webb, S.D., Hulbert, Jr., R.C., Lambert, W.D., 1995. Climatic implications of largeherbivore distributions in the Miocene of North America. In: Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle, L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 91-108. Wheeler, E.F., Matten, L.C., 1977. Fossil wood from an upper Miocene locality in northeastern Colorado. Botanical Gazette 138 (1), 112-118. Wiley, E.O., McNyset, K.M., Townsend, A.T., Robins, C.R., Stewart, A.M., 2003. Niche modeling and geographic range predictions in the marine environmemt using a machine-learning algorithm. Oceonography 16 (3), 120-127. Woodburne, M.O., 1959. A fossil alligator from the lower Pliocene of Oklahoma and its climatic significance. Papers of the Michigan Academy of Science, Arts, and Letters 44, 47-50. Woodburne, M.O., 1996. Reappraisal of the Cormohipparion from the Valentine Formation, Nebraska. American Museum of Novitiates 3163, 56 pp. Woodruff, R., Savin, S.M., Douglas, R.G., 1981. Miocene stable isotope record: a detailed deep Pacific Ocean study and its paleoclimatic implications. Science 212, 665-668. Zachos, J.C., Pegani, M., Stone, L., Thomas, E., Billups, K., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292, 686-693. Zubakov, V.A., Borzenkova, I.I., 1990. Global Palaeoclimate of the Late Cenozoic. Elsevier, Amsterdam., 456 pp.

106 CHAPTER 4: CONCLUSION

Previous work on the evolution of Equinae has primarily focused on the morphological differences between species. The combination of phylogenetic biogeography and ecological niche modeling employed in this thesis provides an in-depth understanding of the biogeography and evolution of the Equinae clade within a paleoecological framework. Biogeographic analyses, in general, provide insight into the interaction between an organism and its environment (Lomolino et al., 2006). Together, the biogeographical analyses used here examined how both ecological and historical factors of the environment influenced the evolutionary patterns of Equinae. In addition, they examined the biogeography of Equinae at the regional and local level, so that general distributional patterns could then be examined on a finer scale and distributional patterns at a fine scale could be placed in a regional context. Specifically, the phylogenetic biogeographic analysis in Chapter 2 examined how historical variables, such as tectonic activity and climatic setting influenced the evolution of the clade. The results indicate that the changing climate during the Miocene was the primarriver of speciation within the clade. The cyclical patterns associated with the climate change resulted predominantly in speciation by geodispersal as climatic barriers rose and fell between regions of North America. The phylogenetic biogeographic study also provided historical information about relationships between the four regions in the study. The Great Plains and Southwest regions were the most recent regions to be separated through vicariance and also most recently experienced dispersal between them. This relationship is consistent with the geological setting of the Miocene. Compressional

107 tectonism off the Pacific coast resulted in uplift of the Rocky Mountains in pulses of active uplift and tectonic quiesence, promoting cyclical dispersal patterns, or geodispersal, between the two regions. In Chapter 3, ecological niche modeling was used to examine the distribution and evolution of equids at the ecosystem level in the Great Plains. The changing climate resulted in patchy vegetation and habitat fragmentation in the Great Plains during the middle Miocene. This distributional pattern occurred simultaneously with the radiation of the Equinae, suggesting vicariant speciation due to habitat fragmentation was a primary driver of speciation that occur within the Great Plains. As climate cooled dramatically during the middle Miocene, species with larger geographic ranges were more successful in surviving from one NALMA to another while species with small ranges became extinct. As climate continued to deteriorate, however, differential range size no longer conferred a survival benefit. Those species that could, tracked their habitat. By the early Pliocene, the preferred habitat of the majority of species was no longer present in the Great Plains. Only those species adapted to steppe habitats thrived, such as Equus simplicidens, an ancestral species of the modern horse. Other species migrated to other regions of North America or became extinct. Predicted species distributions from niche modeling are consistent with regional patterns observed from the phylogenetic biogeographic analysis. Five species determined to have dispersed into the Great Plains from the Southwest in Chapter 2, occupy ranges on the western margin of the Great Plains in their predicted distribution in Chapter 3. In addition, there is an overall southward shift of predicted species ranges from the GARP

108 analysis. Retreat to the Gulf Coast region by several mammalian groups has been suggested previously (Webb et al., 1995) and both the phylogenetic biogeographic and niche modeling analyses support this hypothesis. In conclusion, climatic change was the primary factor influencing the radiation and decline of the Equinae clade. Climate affected the distribution and evolution of equids at local and regional levels from both a historical and ecological biogeographic perspective. Although it has been previously hypothesized that the evolution of the Equinae clade was the result of climate change (e.g., MacFadden, 1993; Hulbert, 1993; Webb et al., 1995), this is the first study to use quantitative biogeographic methods incorporating statistical methods and models to test it. This study represents the first use of ENM on an extinct continental clade and the first use of phylogenetic biogeography on fossil mammals. The results of this thesis demonstrate the potential for both methods in paleontology. By analyzing paleobiogeographic patterns within a quantitative historical and ecological framework, studies such as this, which focus on the role of climate change in driving the evolution of a clade can provide baseline information for studies of the modern biodiversity crisis. These methods are particularly helpful for conservation studies that can use them to determine how climate change will affect the distribution of endangered species as the modern climate changes and habitat degradation continues in the modern world.

109 References

Hulbert, Jr., R.C., 1993. Taxonomic evolution in North American Neogene horses (Subfamily Equinae): the rise and fall of an adaptive radiation. Paleobiology 19 (2), 216-234. Lomolino, M.V., Riddle, B.R., Brown, J.H., 2006. Biogeography, 3rd Edition. Sinauer Associates, Sunderland, Massachusetts, 845 pp. MacFadden, B.J., 1992. Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge University Press, Cambridge, England, 369 pp. Webb, S.D., Hulbert, Jr., R.C., Lambert, W.D., 1995. Climatic implications of largeherbivore distributions in the Miocene of North America. In: Vrba, E.S., Denton, G.H., Partridge, T.C., Burckle, L.H. (Eds.), Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, New Haven, Connecticut, pp. 91-108.

110 APPENDIX A: VICARIANCE AND GEODISPERSAL MATRIX Biogeographic character states for the Lieberman-modified Brooks Parsimony Analysis data matrix for the vicariance and geodispersal analysis. Ancestor refers to the ancestral biogeographic region of the subfamily Equinae. Character states are nodes and terminal taxa of the clade. Absence of the taxa in a region is represented by 0. Presence of the taxa is coded 1. The derived condition is represented by 2.

111

112 APPENDIX B: PUBLISHED REFERENCES FOR GEOGRAPHIC LOCATION DATA Akersten, W. A., 1972. Red Light Fauna (Blancan) of the Love Formation, Southeastern Hudspeth County, Texas. Texas Memorial Museum Bulletin 20, 1-53. Alroy, J., 2002. Synonomies and reidentification of North American fossil mammals. http://paleodb.org Azzaroli, A., 1988. On the Equid genus Dinohippus Quinn 1955 and Pliohippus Marsh 1874. Bolletino della Societa Paleontologica Italiana 27, 61. Barghoorn, S. F., Tedford, R. H., 1993. Road log; Neogene geology of teh Espanola Basin, New Mexico. New Mexico Museum of Natural History and Science Bulletin 2, 169-178. Baskin, J. A., 1991. Early Pliocene horses from Late Pleistocene fluvial deposits Gulf Coastal Plain South Texas. Journal of Paleontology 65, 995-1006. Becker, J. J., 1985. Fossil herons (Aves; Ardeidae) of the late Miocene and early Pliocene of Florida. Journal of Vertebrate Paleontology 5, 24-31. Bennett, D. K., 1979. The fossil fauna from Lost and Found Quarries (Hemphillian: latest Miocene), Wallace County, Kansas. Occasional Papers of the Museum of Natural History, University of Kansas 79, 1-24. Berta, A., Galiano, H., 1983. Magantereon hesperus from the late Hemphillian of Florida with remarks on the phylogenetic relationships of machairodonts (Mammalia, Felidae, Machairodontinae. Journal of Paleontology 57, 892-899. Black, C. C., 1963. A review of the North American Tertiary Sciuridae. Bulletin of the Museum of Comparative Zoology 130, 109-248. Bode, F. D., 1934. The fauna of the Merychippus zone, north Coalinga District, California. Carnegie Institution of Washington Publication 453, 65-96. Bode, F. D., 1935. The fauna of the Merychippus zone, north Coalinga District, California. Carnegie Institution of Washington Publication, 435. Bryant, J. D., 1991. New early Barstovian (Middle Miocene) vertebrates from the Upper Torreya Formation, eastern Florida panhandle. Journal of Vertebrate Paleontology 11, 472-489.

113 Bryant, J. D., MacFadden, B. J., et al., 1992. Improved chronologic resolution of the Hawthorn and the Alum Bluff groups in northern Florida; implications for Miocene chronostratigraphy. Geological Society American Bulletin 104, 208-218. Burns, J. A., Young, R. R., 1988. Stratigraphy and palaeontology of the Hand Hills region. Occasional Papers of the Tyrell Museum of Paleontology 9. Cassaliano, M. L., 1999. Biostratigraphy of Blancan and Irvingtonian mammals in the Fish Creek-Vallecito Creek section, southern California, and a review of the Blancan-Irvingtonian boundary. Journal of Vertebrate Paleontology 19, 169-186. Cassiliano, M. L., 1980. Stratigraphy and vertebrate paleontology of the Horse CreekTrail Creek area, Laramie County, Wyoming. Contributions to Geology 19, 2568. Czaplewski, N. J., 1993. Late Tertiary bats (Mammalia, Chiroptera) from the southwestern United States. Southwestern Naturalist 38, 111-118. Czaplewski, N. J., Bailey, B. E., Corner, R.G., 1999. Tertiary bats (Mammalia: Chiroptera) from northern Nebraska. Transactions of the Nebraska Academy of Sciences 25, 83-93. Czaplewski, N. J., Thurmond, J. P., Wyckoff, D.G., 2001. Wild Horse Creek a late Miocene (Clarendonian-Hemphillian) vertebrate fossil assemblage in Roger Mills County, Oklahoma. Oklahoma Geology Notes 61, 60-67. Dalquest, W., Donovan, T., 1973. A new three toed horse (Nannippus) from the late Pliocene of Scurry County, Texas. Journal of Paleontology 47, 34-45. Dalquest, W. W., Baskin, J. A., Schultz, G.E., 1996. Fossil mammals from a late Miocene (Clarendonian) site in Beaver County, Oklahoma. In: Genoways, H. H. and Baker, R. J. (Eds), Contributions in Mammology: A Memorial Volume Honoring Dr. J. Knox Jones, Jr. Museum of Texas Tech University, 107-137. Dalquest, W. W., Hughes, J. T., 1966. A new mammalian local fauna from the lower Pliocene of Texas. Transactions of the Kansas Academy of Sciences 69, 79-87. Domning, D. P., 1978. Sirenian evolutuion in the North Pacific Ocean. University of California Publications in Geological Sciences 118, 1-176. Domning, D. P., 1990. Fossil Sirenia of the West Atlantic and Caribbean region; IV, Corystosiren varguezi, gen. et sp. nov. Journal of Vertebrate Paleontology 10, 361-371.

114 Emry, R. J., Eshelman, R. E., 1998. The early Hemingfordian (Early Miocene) Pollack Farm local fauna: first Tertiary land mammals described from Delaware. Deleware Geological Survey Special Publication 21, 153-173. Evander, R. L., 1993. Astrohippus walked on faerie toes. Journal of Vertebrate Paleontology 13, Evander, R. L., 1991. Calippus placidus is present at all stratigraphic levels of the Ogallala Group of the Niobrara River valley. Journal of Vertebrate Paleontology 11, 27-28. Feranec, R. S., MacFadden, B. J., 2006. Isotopic discrimination of resource partitioning among ungulates in C-3-dominated communities from the Miocene of Florida and California. Paleobiology 32, 191-205. Firby, J. R., 1966. New non-marine Mollusca from the Esmeralda Formation, Nevada. Proceedings of the California Academy of Sciences 33, 453-479. Forsten, A., 1975. The fossil horses of the Texas Gulf Coastal Plain; a revision. Texas Memorial Museum 22. Forsten, A. , 1991. Size trends in Holarctic anchitherines (Mammalia, Equidae). Journal of Paleontology 65, 147-159. Galbreath, E. C. ,1953. A contribution to the Tertiary geology and paleontology of northeastern Colorado. University of Kansas Paleontological Institute, Galusha, T., Johnson, N. M., Lindsay, E.H., Opdyke, N.D., Tedford, R.H., 1984. Biostratigraphy and magnetostratigraphy, late Pliocene rocks, 111 Ranch, Arizon. Geological Society American Bulletin 95, 714-722. Green, M., 1971. Additions to the Mission vertebrate fauna, lower Pliocene of South Dakota. Journal of Paleontology 45, 486-490. Gregory, J. T., 1942. Pliocene vertebrates from Big Spring Canyon, South Dakota. University of California Publications, Bulletin of the Department of Geological Sciences 26, 307-445. Hager, M. W., 1975. Late Pliocene and Pleistocene history of the Donnelly Ranch vertebrate fauna, southeastern Colorado. Contributions to Geology, Special Paper 2, 3-62.

115 Harrison, J. A., 1978. Mammals of the Wolf Ranch local fauna, Pliocene of the San Pedro Valley, Arizona. Occasional Papers of the Museum of Natural History, University of Kansas 73, 1-18. Harrison, J. A., 1983. The Carnivora of the Edson local fauna (late Hemphillian), Kansas. Smithsonian Contributions to Paleobiology 54. Hesse, C. J., 1936. A Pliocene vertebrate fauna from Optima, Oklahoma. University of California Publications, Bulletin of the Department of Geological Sciences 24, 57-69. Hesse, C. J., 1943. A preliminary report of the Miocene vertebrate faunas of southeast Texas. Transactions and Proceedings of the Texas Academy of Science 26, 157179. Hibbard, C. W., 1954. A new Pliocene vertebrate fauna from Oklahoma. Papers of the Michigan Academy of Science, Arts, and Letters 39, 339-359. Hibbard, C. W., 1956. Vertebrate fossils from the Meade Formation of southwestern Kansas. Papers of the Michigan Academy of Science, Arts, and Letters 41, 145203. Honey, J. G., Izett, G. A., 1988. Paleontology, taphonomy, and stratigraphy of the Browns Park Formation (Oligocene and Miocene) near Maybell, Moffat County, Colorado. United States Geological Survey Professional Paper 1358. Hulbert, R. C., 1982. Population dynamics of the three-toed horse Neohipparion from the late Miocene of Florida. Paleobiology 8, 159-167. Hulbert, R. C., 1987. Late Neogene Neohipparion (Mammalia, Equidae) from the Gulf Coastal Plain of Florida and Texas. Journal of Paleontology 61, 809-830. Hulbert, R. C., 1988. Calippus and Protohippus (Mammalia, Perissodactyla, Equidae) from the Miocene (Barstovian-early Hemphillian) of the Gulf Coastal Plain. Bulletin of the Florida Museum of Natural History, Biological Sciences 33, 221340. Hulbert, R. C., 1988. Cormohipparion and Hipparion (Mammalia, Perissodactyla, Equidae) from the Late Neogene of Florida. Bulletin of the Florida State Museum, Biological Sciences 33, 229-338. Hulbert, R. C., 1989. Phylogenetic interrelationships and evolution of North American late Neogene Equidae. In: Prothero, D.R. and Schoch, R.M. (Eds), Evolution of Perissodactyls, Oxford Monographs on Geology and Geophysics 15, 176-196.

116

Hulbert, R. C., 1993. Late Miocene Nannippus (Mammalia: Perissodactyla) from Florida, with a description of the smallest Hipparionine horse. Journal of Vertebrate Paleontology 13, 350-366. Hulbert, R. C., Czaplewski, N. J., Webb, S.D., 2000. New records of Pseudhipparion simpsoni (Equidae) from the latest Hemphillian of Oklahoma and Florida. Journal of Vertebrate Paleontology 20, Suppl 3. Hulbert, R. C., Czaplewski, N. J., Webb, S.D., 2005. New Records of Pseudhipparion simpsoni (Mammalia, equidae) from the late Hemphillian of Oklahoma and Florida. Journal of Vertebrate Paleontology 25, 737-740. Hulbert, R. C., MacFadden, B. J., 1991. Morphological Transformation and Cladogenesis at the base of the adaptive radiation of Miocene hysodont horses. American Museum Novitates 3000, 2-61. Hulbert, R. C., Morgan, G. S., 1989. Stratigraphy, paleoecology, and vertebrate fauna of the Leisey Shell Pit local fauna, early Pleistocene (Irvingtonian) of southwestern Florida. Papers in Florida Paleontology 2. Hulbert, R. C., Poyer, A., Webb, S.D., 2002. Tyner Farm, a new early Hemphillian local fauna from north-central Florida. Journal of Vertebrate Paleontology 22, Suppl 3, 68A. Hulbert, R. C., Whitmore, F. C.,1997. Early Hemphillian mammals from the Mauvilla local fauna, Alabama. Journal of Vertebrate Paleontology 17. Hulbert, R. C., Whitmore, F. C., 2006. Late Miocene mammals from the Mauvilla Local Fauna, Alabama. Bulletin of the Florida Museum of Natural History 46, 1-28. James, G. T., 1963. Paleontology and nonmarine stratigraphy of the Cuyama Valley badlans, California; Part 1 Geology, faunal interpretations, and systamatic descriptions of Chiroptera, Insectivora, and Rodentia. University of California Publications in Geological Sciences 45, 1-154. Johnston, C. S., 1937. Calippus regulus from the Clarendon beds of Donley County, Texas. Am. Miidland Naturalist 18, 905-907. Johnston, C. S., Savage, D. E., 1955. Introduction, description of localities, preliminary faunal lists, Part 1 of a survey of various late Cenozoic vertebrate faunas of the Panhandle of Texas. University of California Publications in Geological Sciences 31, 27-49.

117 Karrow, P. F., Auffenberg, K., Morgan, G.S., Portell, R.W., Seymour, K.L., Simons E., 1996. Middle Pleistocene (early Rancholabrean) vertebrates and associated marine and non-marine invertebrates from Oldsmar, Pinellas County, Florida. In: Stewart, K. W. (Eds), Palaeoecology and palaeoenvironments of late Cenozoic mammals; tributes to the career of C.S. (Rufus) Churcher, 97-133. Kelly, T. S., 1995. New Miocene horses from the Caliente Formation, Cuyama Valley badlands, California. Contributions in Science (Los Angeles) 455, 1-33. Kelly, T. S., 1998. New middle Miocene equid crania from California and their implications for the phylogeny of the Equini. Contributions in Science (Los Angeles) 473, Kelly, T. S., 1998. New Miocene mammalian faunas from west central Nevada. Journal of Paleontology 72, 137-149. Lambert, W. D., 1997. The osteology and paleoecology of the giant otter Enhydritherium terraenovae. Journal of Vertebrate Paleontology 17, 738-749. Leite, M. B., 1990. Stratigraphy and mammalian paleontology of the Ash Hollow Formation (upper Miocene) on the north shore of Lake McConaughy, Keith County, Nebraska. Contributions to Geology, University of Wyoming 28, 1-29. Macdonald, J. R., Pelletier, W. J., 1958. The Pliocene mammalian faunas of Nevada, U.S.A. Paleontologia, taxonomia y evolucion. Ciudad de Mexico: International Geological Congress, 1956 Report of the 7th Session 7, 365-388. MacFadden, B. J., 1977. Magnetic polarity stratigraphy of the Chamita Formation stratotype (Mio-Pliocene) of North-central New Mexico. American Journal of Sciences 277, 769-800. MacFadden, B. J., 1984. Astrohippus and Dinohippus from the Yepomera local fauna (Hemphillian, Mexico) and implications for the phylogeny of one-toed horses. Journal of Vertebrate Paleontology 4, 273-283. MacFadden, B. J., 1984. Systematics and phylogeny of Hipparion, Neohipparion, Nannipus and Cormohipparion (Mammalia, Equidae) from the Miocene and Pliocene of the New World. Bulletin of the American Museum of Natural History 179, 1-195. MacFadden, B. J., 1985. Patterns of Phylogeny and Rates of Evolution in Fossil Horses: Hipparions from the Miocene and Pliocene of North America. Paleobiology 11, 245-257.

118 MacFadden, B. J., 1986. Fossil horses from "Eohippus" (Hyracotherium) to Equus; scaling, Cope's Law, and the evolution of body size. Paleobiology 12, 355-369. MacFadden, B. J., 1986. Late Hemphillian Monodactyla Horses Mammalia Equidae from the Bone Valley Formation of Central Florida USA. Journal of Paleontology 60, 466-475. MacFadden, B. J., 1997. Pleistocene horses from Tarija, Bolivia, and validity of the genus Onohippidium (Mammalia, Equidae). Journal of Vertebrate Paleontology 17, 199-218. MacFadden, B. J., Carranza-Castaneda, O., 2002. Cranium of Dinohippus mexicanus (Mammalia, Equidae) from the early Pliocene (latest Hemphillian) of central Mexico, and the origin of Equus. Bulletin of the Florida Museum of Natural History 43. MacFadden, B. J., Skinner, M. F., 1979. Diversification and biogeography of the onetoed horses Onohippidium and Hippidion. Postilla 175. MacFadden, B. J., Waldrop, J. S., 1980. Nannippus phlegon (Mammalia, Equidae) from the Pliocene (Blancan) of Florida. Bulletin of the Florida State Museum, Biological Sciences 25, 1-37. Matthew, W. D., Stirton, R. A., 1930. Equidae of the Pliocene of Texas. University of California Publications, Bulletin of the Department of Geological Sciences 19, 349-396. Merriam, J. C., 1915. New species of the Hipparion group from the Pacific coast and Great Basin provinces of North America. University of California Publications, Bulletin of the Department of Geological Sciences 9, 1-8. Morgan, G. S., 1989. Miocene paleontology and stratigraphy of the Suwannee River basin of North Florida and South Georgia. Southeastern Geological Society Field Conference Guidebook 30. Morgan, G. S., 1993. Mammalian biochronology and marine-nonmarine correlations in the Neogene of Florida. In: (Eds), Neogene of Florida and adjacent regions; proceedings of the Third Bald Head Island conference on Coastal plains geology. Special Publication, Florida Geological Survey, 55-66. Morgan, G. S., 1994. Miocene and Pliocene marine mammal faunas from the Bone Valley Formation of Central Florida. Contributions in Marine Mammal Paleontology Honoring Frank C. Whitmore Jr., Proceedings of the San Diego Society of Natural History 29, 239-268.

119

Morgan, G. S., Estep, J. W., Heckert, A.B., Lucas, S.P., Sealey, P.L., Williamson, T.E., 1997. Pliocene (latest Hemphillian and Blancan) vertebrate fossils from the Mangas Basin, southwestern New Mexico. Bulletin of the New Mexico Museum of Natural History and Science 11, 97-128. Morgan, G. S., Pratt, A. E., 1988. An early Miocene (late Hemingfordian) vertebrate fauna from Brooks Sink, Bradford County, Florida. In: Pirkle, F. L. (Eds), Southeastern Geological Society Field Conference Guidebook53-69. Morgan, G. S., Sealey, P. L., 1995. Late Miocene and Pliocene (Hemphillian and Blancan) vertebrate fossils from the Gila Group, southwestern New Mexico. New Mexico Geology 17, 30. Munthe, J., 1979. The Hemingfordian mammal fauna of the Vedder locality, Branch Canyon Sandstone, Sanat Barbara County, California, Part 3: Carnivoria, Perissodactyla, Artiodactyla and summary. PaleoBios 29, 1-22. Munthe, J., 1988. Miocene mammals of the Split Rock area, Granite Mountains basin, central Wyoming. University of California Publications in Geological Sciences 126, 1-136. Olsen, S. J., 1964. The stratigraphic importance of a Lower Miocene vertebrate fauna from north Florida. Journal of Paleontology 38, 477-482. Passey, B. H., Cerling, T. E., Perkins, M., Tucker, S.T., 1999. Timing and nature of C4 biomass expansion in Nebraska. Abstracts with Programs - Geological Society of America 31, 341. Quinn, J. P., 1987. Stratigraphy of the middle Miocene Bopesta Formation, souther Sierra Nevada, California. Contributions in Science (Los Angeles) 393, Repenning, C. A., Tedford, R. H., 1977. Otarioid seals of the Neogene. Geological Survery Professional Paper 992, 1-93. Reynolds, R. E., Pajak III, A. F., Reynolds, R.L., Whistler, D.P., 1991. Blancan, Irvingtonian, and Rancholabrean land mammal age faunas from western Riverside County, California. Quarterly of San Bernardino County Museum Association 38. Richey, K. A., 1948. Lower Pliocene horses from Black Hawk Ranch, Mount Diablo, California. University of California Publications, Bulletin of the Department of Geological Sciences 28, 1-44.

120 Savage, D. E., 1941. Two new middle Pliocene carnivores from Oklahoma, with notes on the Optima fauna. American Midland Naturalist 25, 692-710. Savage, D. E., 1955. Nonmarine lower Pliocene sediments in California; a geochronologic-stratigraphic classification. University of California Publications in Geological Sciences 31. Scharf, D. W., 1935. A Miocene mammalian fauna from Sucker Creek, southeastern Oregon. Carnegie Institution of Washington Publication 453, 97-118. Schiebout, J. A., Ting, S., 2000. Paleofaunal survey, collecting, processing and documentation at locations in the Castor Creek Member, Miocene Fleming Formation, Fort Polk, Louisiana. Louisiana State University Report to the Corps of Engineers, Fort Worth District, Texas, USA. Schultz, G. E., 1977. Blancan and post-Blancan faunas in the Texas Panhandle. In: (Eds), Guidebook, field conference on late Cenozoic biostratigraphy of the Texas Panhandle and adjacent Oklahoma, 105-145. Schultz, G. E., 1990. Late Hemphillian faunas of the Texas and Oklahoma panhandles. In: Gustavson, T. C. (Eds), Tertiary and Quaternary stratigraphy and vertebrate paleontology of parts of northwestern Texas and eastern New Mexico; Guidebook - Bureau of Economic Geology, University of Texas at Austin, 104-111. Schultz, G. E., 1990. Stop 14: The Clarendonian faunas of Texas and Oklahoma panhandles. In: Gustavson, T. C. (Eds), Tertiary and Quaternary stratigraphy and vertebrate paleontology of parts of northwestern Texas and eastern New Mexico; Guidebook - Bureau of Economic Geology, University of Texas at Austin, 83-93. Sellards, E. H., 1916. Fossil vertebrates from Florida: A new Miocene fauna; new Pliocene species; the Pleistocene fauna. Florida State Geological Survey Annual Report 8, 79-119. Shotwell, J. A., 1968. Miocene mammals of southeast Oregon. Bulletin of the Museum of Natural History, University of Oregon 14. Simpson, G. G., 1930. Tertiary land mammals of Florida. Bulletin of the American Museum of Natural History 59, 149-211. Simpson, G. G., 1932. Miocene land mammals from Florida. Bulletin of the Florida State Geological Survey 10, 7-41.

121 Skinner, M. F., 1968. A Pliocene chalicothere from Nebraska and distribution of chalicotheres in the late Tertiary of North America. American Museum Novitates 2346. Skinner, M. F., Gooris, R. J., Skinner, S.M., 1968. Cenozoic rocks and faunas of Turtle Butte, south-central South Dakota. Bulletin of the American Museum of Natural History 138, 381-436. Skinner, M. F., Johnson, F. W., 1984. Tertiary stratigraphy and the Frick Collection of fossil vertebrates from the north-central Nebraska. Bulletin of the American Museum of Natural History 178, 1-368. Skinner, M. F., Gooris, R.J., Skinner, S. M., 1977. Stratigraphy and biostratigraphy of late Cenozoic deposits in central Sioux County, western Nebraska. Bulletin of the American Museum of Natural History 158, 263-370. Stirton, R. A., 1939. Cenozoic mammal remains from the San Francisco Bay region. University of California Publications, Bulletin of the Department of Geological Sciences 24, 339-409. Stirton, R. A., 1940. The Nevada Miocene and Pliocene mammalian faunas as faunal units. Proceedings of the Sixth Pacific Science Conference 2, 627-640. Stirton, R. A., Chamberlain, W., 1939. A cranium of Pliohippus fossulatus from the Clarendon lower Pliocene fauna of Texas. Journal of Paleontology 13, 349-353. Tabrum, A., 1981. A contribution to the mammalian paleontology of the Ogallala Group of South-central South Dakota. Rapid City, SD, South Dakota School of Mines and Technology. Master's, 408p. Tedford, R. H., 1981. Mammalian biochronology of the late Cenozoic basin of New Mexico. Geological Society American Bulletin 92, 1008-1022. Tedford, R. H., Galusha, T., Skinner, M.F., Tayler, B.E., Fields, R.W., Macdonald, J.R., Rensberger, J.M., Webb, S.D., Whistler, D.P., 1987. Faunal succession and biochronology of the Arikeean through Hemphillian interval (late Oligocene through earliest Pliocene epochs) in North America. In: Woodburne, M. O. (Eds), Cenozoic Mammals of North America: Geochronology and biostratigraphy153210. Thomasson, J. R., LaGarry, H. E., Mergen, D.E., Zakrzewski, R.J., 1990. A late Miocene (late early Hemphillian) biota from northwestern Kansas. National Geographic Research 6, 231-244.

122 Turner, M. A., 1972. A faunal assemblage from the lower Ash Hollow Formation (Neogene) of southern Nebraska. Lincoln, NE, University of Nebraska. Master's. Voorhies, M. R., 1969. Taphonomy and population dynamics of an Early Pliocene vertebrate fauna, Knox County, Nebraska. University of Wyoming Contributions to Geology Special Paper 1, 1-69. Voorhies, M. R., 1974. Fossil pocket mouse burrows in Nebraska. American Midland Naturalist 91, 492-498. Voorhies, M. R., 1984. "Citellus kimballensis" Kent and "Propliophenacomys uptegrovensis" Martin, supposed Miocene rodents, are Recent intrusives. Journal of Paleontology 58, 254-258. Voorhies, M. R., 1990. Vertebrate biostratigraphy of the Ogallala group in Nebraska. In: Gustavson, T. C. (Eds), Geologic Framework and Regional Hydrology: Upper Cenozoic Blackwater Draw and Ogallala Formations, Great PlainsBureau of Economic Geology, University of Texas, Austin, 115-151. Voorhies, M. R., 1990. Vertebrate paleontology of the proposed Norden Rservoir Area, Brown, Cherry and Keya Paha counties, Nebraska. Technical Report, Division of Archeological Research, Department of Anthropology, University of Nebraska 82-90. Voorhies, M. R., Corner, R. G., Fitzgibbon, J.L., 1987. Calippus regulus (Mammalia: Equidae) in the Penny Creek local fauna (Clarendonian), Webster County, Nebraska. Transactions of the Nebraska Academy of Sciences 15, 75-82. Wagner, H., 1976. A new species of Pliotaxidae (Mustelidae; Carnovia) from California. Journal of Paleontology 50, 107-127. Wagner, H. M., Demere, T.A., Prothero, D.R., Riney, B. O., 2001. Magnetic stratigraphy and land mammal biochronology of the nonmarine facies of the Pliocene San Diego Formation, San Diego County, California. In: Prothero, D. R. (Eds), Magnetic Stratigraphy of the Pacific Coast Cenozoic, 359-368. Wallace, S. C., 1997. Mammals of the Rhino Hill West local fauna, Miocene (Hemphillian), Wallace County, Kansas. Hays, KS, Fort Hays State University. Master's: 142. Webb, S. D., 1969. The burge and minnechaduza Clarendonian mammalian faunas of North-Central Nebraska. University of California Publications in Geological Sciences 78.

123 Webb, S. D., Hulbert, R. C., 1986. Systematics and evolution of Pseudohipparion (Mammalia, Equidae) from the Late Neogene of the Gulf Coastal Plain and the Great Plains. Contributions to Geology, University of Wyoming, Special Paper 3, 237-272. Whistler, D. P., Burbank, D. W., 1992. Miocene biostratigraphy and biochronology of the Dove Spring Formation, Mojave Desert, California, and characterization of the Clarendonian mammal age (late Miocene) in California. Geological Society American Bulletin 104, 644-658. White, T. E., 1942. The Lower Miocene mammal fauna of Florida. Bulletin of the Museum of Comparative Zoology 92, 1-49. Wilson, R. L., 1968. Systematics and faunal analysis of a Lower Pliocene vertebrate assemblage from Trego, Kansas. Contributions from the Museum of Paleontology, University of Michigan 22, 75-126. Winkler, D. A., 1990. Stop 3; Ogallala Formation (Group) exposed at Janes Quarry. In: Gustavson, T. C. (Eds), Bureau of Economic Geology Guidebook, 38-40. Winkler, D. A., 1990. Stop 4; Type section of the Couch and Bridwell formations, Ogallala Group at Blanco Canyon, Silver Falls area. In: Gustavson, T. C. (Eds), Bureau of Economic Geology Guidebook41-43. Woodburne, M. O., 1996. Reappraisal of the Cormohipparion from the Valentine Formation, Nebraska. American Museum Novitates 3163. Woodburne, M. O., 2005. A new occurrence of Cormohipparion, with implications for the Old World Hippotherium datum. Journal of Vertebrate Paleontology 25, 256257. Wright, D. B., Webb, S. D., 1984. Primitive Mylohyus (Artiodactyla; Tayassuidae) from the late Hemphillian bone Valley of Florida. Journal of Vertebrate Paleontology 3, 152-159. Zakrzewski, R. J., 1988. Preliminary report on fossil mammals from the Ogallala (Miocene) or north-central Kansas. Fort Hayes Studies, Science, third series 10, 117-127.

124 APPENDIX C: SPECIES OCCURRENCE DATA FOR THE GREAT PLAINS Geographic location data for all species belonging to Equinae in the Great Plains, along with the formation it was found in, the age of the site and the time slice it belonged to. Ages are given in NALMAs with the following abbreviations: E – early, M – middle, L – late, AK – Arikareean, HMF – Hemingfordian, BAR – Barstovian, CLAR – Clarendonian, HP- Hemphillian, BLAN – BLAN. Only species with 5 or more geographically distinct locations were used in the GARP analysis.

Genus Genus Merychippus Cormohipparion Merychippus Cormohipparion Merychippus Cormohipparion Merychippus Cormohipparion Merychippus Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion

Species Species sphenodus occidentale sphenodus occidentale sphenodus occidentale sphenodus occidentale sphenodus occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale quinni occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale

SiteName Name Site Eubanksof Little White River Canyon Pawnee Buttes Little Beaver B 3 Points PitA Big Beaver HorseRim and Locality Mastodon Quarry North West Quarry Crooked Creek Locality NordenBurge Bridge Above B Quarry Railway Quarry A Leptarctus B Verdigre Quarry McGinley's Stadium Devil's Gulch Horse Quarry Fat Chance Locality Devil's Quarry Jump Off Quarry Bluejay NenzelQuarry Quarry Kepler Sawyer Quarry North Shore Schoettger Quarry Lonergan Creek Kennesaw I Big Toad Beach Kennesaw II Poison Ivy Quarry Uhl Pit Chokecherry Quarry 1 mi. W River of Sand Canyon Niobrara Valley Durham Quarry Kilpatrick GallupHill Gulch Olcott Hollow Horn Bear Quarry Olcott Quarry Long Island Quarry Above Middlebranch Soldier Creek no. 6 East Clayton Quarry Soldier Creek no. 10 Wade Quarry Soldier Creek 17 Balanced Rock no. Quarry Spirit MoundQuarry Machaerodus Jack Swayze Xmas Quarry Quarry WolfKat Creek V526 East Quarry WolfJohnson Creek V527 Hans Quarry Wolf Creek V529 Leptarctus Quarry WolfKat Creek V5324 Line Quarry Wolf Creek Quarter Line V5325 Kat Quarry WolfLine Creek V5328 West Kat Quarry Wolf Creek V5329 Wakeeney (KU Loc. 29) Wolf Creek V5333 Minium Quarry Turtle ButteQuarry (West Gap) Whisenhunt Big Spring Canyon Big Spring Canyon Big Spring Canyon Big Spring Canyon

Lat Lat 40.52 43.16 40.49 42.55 40.51 42.55 40.49 42.55 40.49 42.55 42.47 42.44 42.50 42.53 42.29 42.45 42.42 42.48 42.49 42.23 42.48 41.40 42.41 41.16 42.57 41.16 40.59 41.17 40.59 42.25 40.47 42.28 40.59 42.54 35.51 42.10 42.49 42.10 43.09 42.09 39.54 42.33 43.00 42.41 43.00 42.43 43.00 42.53 43.00 42.53 37.22 42.53 43.00 42.53 43.00 42.53 43.00 42.53 43.00 42.53 43.00 42.53 43.00 42.53 43.01 39.05 43.00 39.24 43.04 36.45 43.07 43.07 43.07 43.07

Long Long -103.55 -100.55 -103.58 -100.24 -104.00 -100.26 -104.04 -100.27 -104.04 -100.24 -100.02 -100.49 -100.31 -100.15 -98.08 -100.09 -99.47 -100.02 -101.17 -98.06 -101.08 -102.48 -100.51 -101.48 -99.42 -101.48 -103.29 -101.51 -103.30 -98.09 -103.56 -98.05 -103.29 -100.29 -99.57 -103.43 -101.44 -103.43 -101.06 -103.43 -99.31 -98.10 -100.00 -99.55 -100.00 -100.50 -100.00 -100.14 -100.00 -100.14 -99.47 -100.14 -102.24 -100.13 -102.23 -100.13 -102.24 -100.15 -102.24 -100.14 -102.24 -100.14 -102.24 -100.14 -102.24 -99.45 -102.27 -100.08 -99.50 -100.02 -101.56 -101.56 -101.56 -101.56

State State CO SD CO NE CO NE CO NE CO NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE CO NE CO NE CO NE CO NE OK NE NE NE SD NE KS NE SD NE SD NE SD NE SD NE KS NE SD NE SD NE SD NE SD NE SD NE SD NE SD KS SD KS SD OK SD SD SD SD

County County Weld Todd Weld Cherry Weld Cherry Weld Cherry Weld Cherry Brown Cherry Cherry Cherry Knox Brown Brown Keya Paha Cherry Antelope Cherry Morrill Cherry Keith Keya Paha Keith Logan Keith Logan Antelope Weld Knox Logan Cherry Roger Mills Sioux Cherry Sioux Todd Sioux Phillips Knox Todd Brown Todd Cherry Todd Cherry Todd Cherry Clark Cherry Shannon Cherry Shannon Cherry Shannon Cherry Shannon Cherry Shannon Cherry Shannon Cherry Shannon Trego Shannon Graham Tripp Beaver Bennett Bennett Bennett Bennett

Formation Formation Pawnee Creek Ash Hollow Pawnee Creek Ash Hollow Pawnee Creek Ash Hollow Pawnee Creek Ash Hollow Pawnee Creek Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Valentine Ash Hollow Ogallala Group Ash Hollow Ogallala Group Ash Hollow Ogallala Group Ash Hollow Pawnee Creek Ash Hollow Ogallala Snake Creek Ash Hollow Snake Creek Ash Hollow Snake Creek AshHollow Hollow Ash Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ogallala Ash Hollow AshHollow Hollow Ash AshHollow Hollow Ash AshHollow Hollow Ash AshHollow Hollow Ash AshHollow Hollow Ash AshHollow Hollow Ash Ash Hollow Ogallala AshHollow Hollow Ash Valentine Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow

Age Time TimeSlice Slice Age LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR LBAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR EEHP Middle Middle CLAR Middle CLAR Middle Middle CLAR Middle Middle CLAR Middle Middle CLAR Middle EEHP Middle Late CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle CLAR CLAR Middle Middle MCLA CLAR Late Middle LEHP ECLA Middle Middle MCLA CLAR Middle CLAR Middle CLAR Middle CLAR Middle

125

APPENDIX C: SPECIES OCCURRENCE DATA FOR THE GREAT PLAINS

Genus Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Cormohipparion Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus

Species occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale occidentale lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis lenticularis aztecus aztecus

Site Name Exell MacAdams Quarry Grant Quarry General Rowe-Lewis Ranch Quarries Gidley's 3-toed Horse Quarry Sebits Ranch Locality 24-A Sebits Ranch Locality 24-B Box T Lower Couch Formation (TMM 42433) Upper Couch Formation (TMM 947) Janes Quarry Bridwell Formation (TMM 42441) Wray Wild Horse Creek #1 Uptegrove Quarry Honey Creek Mailbox Santee Devil's Nest Airstrip Amebelodon fricki Quarry Aphelops Quarries Wakeeney (UM-K6-59) Edson Quarry Lost Quarry Rhinoceros Hill Optima North Quarry Coffee Ranch Quarry General Goodnight Fauna Capromeryx texanus Site Axtel Janes Quarry Janes Quarry Citellus dotti Site Arnett

Lat 35.38 35.04 35.04 35.06 35.06 36.05 36.05 36.14 33.40 33.39 33.25 33.40 40.04 35.47 41.15 42.41 42.23 42.49 42.49 40.23 42.12 39.05 39.09 38.47 39.07 36.45 39.20 35.44 34.57 36.02 34.55 33.25 33.25 36.55 36.07

Long -101.54 -100.54 -100.54 -100.42 -100.44 -100.00 -100.00 -100.05 -101.07 -101.07 -101.28 -101.11 -102.13 -99.38 -102.54 -98.39 -98.07 -97.51 -97.43 -100.15 -103.47 -99.45 -101.30 -101.29 -101.30 -101.22 -101.44 -100.31 -101.11 -100.31 -101.42 -101.28 -101.28 -100.15 -99.57

State TX TX TX TX TX TX TX TX TX TX TX TX CO OK NE NE NE NE NE NE NE KS KS KS KS OK KS TX TX TX TX TX TX OK OK

County Moore Donley Donley Donley Donley Lipscomb Lipscomb Lipscomb Crosby Crosby Crosby Lubbock Yuma Roger Mills Cheyenne Holt Antelope Knox Knox Frontier Sioux Trego Sherman Wallace Wallace Texas Sherman Hemphill Armstrong Hemphill Randall Crosby Crosby Beaver Ellis

Formation Ogallala Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Ogallala Ogallala Ogallala (Hemphill Beds) Couch Couch Bridwell? Bridwell Ogallala Group Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Snake Creek Ogallala Ogallala Ogallala Ogallala Ogallala Ogallala Hemphill Beds Goodnight Beds Ogallala Goodnight Beds Bridwell? Bridwell? Ogallala Ogallala

Age Time Slice CLAR Middle MCLA Middle MCLA Middle MCLA Middle CLAR Middle EEHP Late EEHP Late LEHP Late MCLA Middle MCLA Middle EEHP Late ELHP Late LEHP Late CLHE Middle ELHP Late ELHP Late ELHP Late LLHP Late LLHP Late LEHP Late LEHP Late MCLA Middle ELHP Late ELHP Late ELHP Late ELHP Late ELHP Late ELHP Late ELHP Late EEHP Late LLHP Late EEHP Late EEHP Late LLHP Late EEHP Late

126


Genus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Nannippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus

Species aztecus aztecus aztecus beckensis peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus peninsulatus insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis insignis

Site Name Bridwell Formation (TMM 42441) Wallace Ranch Johnson's Ranch Beck Ranch Rexriod KU Locality 2 Rexroad KU Locality 3 Angell Member Deer Park Sanders Seger Gravel Pit Channing Cita Canyon Meade's Quarry Red Quarry South Bijou Hill North Bijou Hill Burge Quarry Crooked Creek Locality Norden Bridge Quarry Carrot Top Quarry Welke Locality Crookston Bridge Quarry Railway Quarry A Hottell Ranch Main Quarry Hottell Ranch Horse Quarry Immense Journey Quarry Hazard Homestead Quarry Jamber Quarry Miller Creek Niobrara River Valley Penny Creek Wt-11 East Sand Quarry New Surface Quarry Echo Quarry Echo Quarry Humbug Quarry 23 mi. S of Agate Joe's Quarry

Lat 33.40 33.31 33.31 32.72 37.16 37.16 37.41 37.18 37.28 37.22 35.69 34.96 33.79 33.79 43.29 43.31 42.45 42.55 42.47 42.47 42.46 42.46 42.50 41.32 41.32 41.32 40.03 42.51 42.49 42.54 40.01 42.09 42.09 42.10 42.10 42.10 42.10 41.25

Long -101.11 -101.38 -101.39 -100.74 -100.46 -100.46 -99.88 -100.46 -100.40 -100.48 -102.47 -101.89 -101.26 -101.26 -99.16 -99.16 -100.49 -100.24 -100.02 -100.04 -100.06 -100.47 -100.31 -103.56 -103.56 -103.56 -100.53 -98.46 -97.40 -100.29 -98.33 -103.43 -103.43 -103.44 -103.44 -103.44 -103.45 -104.46

State TX TX TX TX KS KS KS KS KS KS TX TX TX TX SD SD NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE WY

County Lubbock Lubbock Lubbock Scurry Meade Meade Meade Meade Meade Meade Hartley Randall Crosby Crosby Charles Mix Brule Cherry Cherry Brown Brown Brown Cherry Cherry Banner Banner Banner Hitchcock Boyd Knox Cherry Webster Sioux Sioux Sioux Sioux Sioux Sioux Laramie Blanco Blanco Fort Randall Fort Randall Valentine Ash Hollow Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Olcott Olcott Olcott Olcott Olcott Olcott

Rexroad Rexroad Ballard Ballard Ballard Crooked Creek

Formation Bridwell Bridwell Bridwell

Age Time Slice ELHP Late LLHP Late LLHP Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late LBAR Middle LBAR Middle ECLA Middle CLAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle LBAR Middle ECLA Middle EBAR Early EBAR Early EBAR Early EBAR Early EBAR Early EBAR Early HEBA Early

127


Genus Merychippus Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Hipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion

Species insignis forcei forcei tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense tehonense simpsoni simpsoni simpsoni simpsoni skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri skinneri gratum gratum gratum gratum gratum

Site Name Eubanks Amebelodon fricki Quarry Olcott Quarry Long Island Quarry Kepler Quarry East Clayton Quarry Durham Bushy Pine Butte Channel Beaver Quarry Bear Creek Quarry Arnett Rosebud Agency Quarry Trailside Kat Quarry F. Sebastian Place Whisenhunt Quarry MacAdams Quarry Anderson Quarry #2 Wild Horse Creek #1 Kinkerman's Pit Moundridge Gravel Pit 0.75 mi. NE of Buis Ranch Locality Buis Ranch Machaerodus Quarry Line Kat Quarry Durham Leptarctus B Jonas Wilson Quarry Xmas Quarry Connection Kat Quarry Hans Johnson Quarry Kat Quarry Leptarctus Quarry Quarter Line Kat Quarry Trailside Kat Quarry West Line Kat Quarry Above Pocket Mouse Burrows Xmas Quarry Jonas Wilson Quarry Soldier Creek no. 11 Soldier Creek no. 12

Lat 40.52 40.23 42.09 39.54 41.40 42.41 35.51 43.00 36.45 42.53 36.07 43.13 42.53 39.48 36.45 35.04 39.44 35.47 38.27 38.12 36.56 36.55 42.53 42.53 35.51 42.53 42.39 42.53 42.53 42.53 42.53 42.53 42.53 42.53 42.53 42.00 42.53 42.39 43.00 43.00

Long -103.55 -100.15 -103.43 -99.31 -102.48 -99.55 -99.57 -101.00 -100.14 -101.23 -99.57 -100.49 -100.15 -100.32 -100.02 -100.54 -100.41 -99.38 -97.28 -97.31 -100.15 -100.15 -100.14 -100.14 -99.57 -100.15 -100.03 -100.14 -100.15 -100.13 -100.14 -100.15 -100.14 -100.15 -100.14 -98.00 -100.14 -100.03 -100.00 -100.00

State CO NE NE KS NE NE OK SD OK NE OK SD NE KS OK TX KS OK KS KS OK OK NE NE OK NE NE NE NE NE NE NE NE NE NE NE NE NE SD SD

County Weld Frontier Sioux Phillips Morrill Brown Roger Mills Bennett Beaver Cherry Ellis Todd Cherry Decatur Beaver Donley Decatur Roger Mills McPherson McPherson Beaver Beaver Cherry Cherry Roger Mills Cherry Brown Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Antelope Cherry Brown Todd Todd

Age LBAR LEHP CLAR EEHP CLAR CLAR CLAR MCLA CLAR EEHP CLAR CLAR EEHP MCLA MCLA EEHP CLHE EEHP EEHP LLHP LLHP CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR LCLAR CLAR CLAR

Formation Pawnee Creek Ash Hollow Snake Creek Ash Hollow Ash Hollow Ash Hollow Ogallala Ogallala Ash Hollow Ogallala Ash Hollow Ash Hollow Ogallala Group Ogallala Clarendon Beds Ogallala Ogallala Delmore Delmore Ogallala Ogallala Ash Hollow Ash Hollow Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow

Time Slice Early Late Middle Late Middle Middle Middle Middle Middle Middle Late Middle Middle Late Middle Middle Late Middle Late Late Late Late Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

128


Genus Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Elk Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion

Species gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum CLAR gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum gratum

Site Name Soldier Creek no. 13 Soldier Creek no. 14 Soldier Creek no. 17 Spirit Mound Rice Ranch Hollow Horn Bear Quarry East Clayton Quarry Cragin Quarry Clayton Quarry Bear Creek Quarry Beads Creek no. 1 Wolf Creek V525 Wolf Creek V526 Wolf Creek V529 Wolf Creek V5324 Wolf Creek V5325 Wolf Creek V5328 Wolf Creek V5329 Wolf Creek V5330 Wolf Creek V5333 Wolf Creek V5335 Big Spring Canyon Big Spring Canyon Big Spring Canyon (Site 11) Mission Fauna Middle Rosebud Agency Quarry Canyon of Little White River Little Beaver B Big Beaver A Crooked Creek Locality Upper County Road Locality Big Beaver C Leptarctus B McGinley's Stadium Jerry Quarry Precarious Quarry Bluejay Quarry

Long -100.00 -100.00 -100.00 -100.00 -101.00 -101.06 -99.55 -100.21 -99.55 -101.23 -100.00 -102.24 -102.24 -102.24 -102.24 -102.24 -102.24 -102.24 -102.21 -102.27 -102.25 -101.56 -101.56 -101.56 -100.36 -100.49 -100.55 -100.24 -100.26 -100.24 -100.28 -100.27 -100.15 -100.09 -100.10 -100.03 -98.06

Lat 43.00 43.00 43.00 43.00 43.00 43.09 42.41 36.45 42.41 42.53 43.00 43.00 43.00 43.00 43.00 43.00 43.00 43.01 42.59 43.00 43.00 43.07 43.07 43.07 43.24 43.13 43.16 42.55 42.55 42.55 42.54 42.55 42.53 42.45 42.45 42.49 42.23

SD SD NE NE NE NE NE NE NE NE NE NE

State SD SD SD SD SD SD NE OK NE NE SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD Todd Todd Cherry Cherry Cherry Cherry Cherry Cherry Brown Brown Keya Paha Antelope

County Todd Todd Todd Todd Bennett Todd Brown Beaver Brown Cherry Todd Shannon Shannon Shannon Shannon Shannon Shannon Shannon Shannon Shannon Shannon Bennett Bennett Bennett Mellette Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow

CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR

Age

Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

Time Slice Middle Middle Middle Middle Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ogallala MCLA Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow CLAR Middle Ash Hollow (maybe some Valentine); Thin

Formation

129


Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion

Genus Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion

Species gratum gratum gratum gratum gratum gratum gratum gratum Middle gratum gratum gratum hessei hessei hessei hessei hessei hessei hessei hessei hessei hessei hessei retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum William's School Whisenhunt Quarry Beaver Quarry Durham Exell Coetas Creek Charles Risley Ranch MacAdams Quarry Grant Quarry General Clarendon Beds Lower Couch Formation (TMM 42433) Upper Couch Formation (TMM 947) Upper Couch Formation (TMM 963) Yoos Quarry Railway Quarry A Midway Quarry Gregory no. 2 Turtle Butte (West Gap) Burge Quarry Burge B Quarry Gordon Creek Quarry Crazy Locality Lull Locality Fence Line Locality Sherman Ranch Locality Sunrise Locality Buzzard Feather Locality Penny Creek Wt-11 Penny Creek Wt-12

Site Name Kepler Quarry Grasz Cat North Shore Lonergan Creek Big Toad Beach Poison Ivy Quarry Chokecherry Quarry Niobrara River Valley 42.41 36.45 36.45 35.51 35.38 35.28 35.04 35.04 35.04 35.04 33.40 33.39 33.41 39.42 42.50 42.53 43.00 43.04 42.45 42.44 42.46 42.41 42.54 42.55 42.49 42.55 42.48 40.01 40.01

Lat 41.40 41.17 41.16 41.16 41.17 42.25 42.28 42.54 -99.55 -100.02 -100.14 -99.57 -101.54 -101.41 -100.52 -100.54 -100.54 -100.48 -101.07 -101.07 -101.10 -100.50 -100.31 -100.14 -99.00 -99.50 -100.49 -100.49 -100.39 -100.51 -100.27 -100.23 -100.06 -100.22 -100.03 -98.33 -98.33

Long -102.48 -101.52 -101.48 -101.48 -101.51 -98.09 -98.05 -100.29 NE OK OK OK TX TX TX TX TX TX TX TX TX KS NE NE SD SD NE NE NE NE NE NE NE NE NE NE NE

State NE NE NE NE NE NE NE NE Brown Beaver Beaver Roger Mills Moore Potter Donley Donley Donley Donley Crosby Crosby Crosby Rawlins Cherry Cherry Gregory Tripp Cherry Cherry Cherry Cherry Cherry Cherry Keya Paha Cherry Keya Paha Webster Webster

CLAR MCLA MCLA CLAR CLAR CLAR MCLA MCLA MCLA MCLA MCLA MCLA MCLA CLAR LBAR ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA ECLA

Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine

Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

Age Time Slice CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle Ash Hollow CLAR

Ash Hollow Ogallala Ogallala Ogallala Ogallala Ogallala Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Couch Couch Couch Ogallala Valentine Valentine

County Formation Morrill Ash Hollow Keith Ash Hollow Keith Ash Hollow Keith Ash Hollow Keith Ash Hollow Antelope Ash Hollow Knox Ash Hollow Cherry, Keya Paha, Boyd

130


Genus Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Pseudhipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion

Species retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum retrusum gidleyi eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle eurystyle

Site Name Lat Penny Creek Wt-13 40.00 June Quarry 42.38 Lucht Quarry 42.40 Verdigre Quarry 42.29 Devil's Gulch Horse Quarry 42.42 Jones Canyon Site 42.42 Trail Creek Quarry 41.25 Escarpment Quarry 41.24 Hamburg (Locality 1) 39.02 Hamburg (Locality 2) 39.02 Hamburg (Locality 3) 39.02 Hamburg (Locality 8) 39.02 Republican River Beds (Phillips County) 39.59 Optima 36.45 Joseph R Thomasson Site 9a 39.00 Lemoyne Quarry 41.17 Ogallala Beach 41.08 Feldt Ranch 41.08 Honey Creek 42.41 Mailbox 42.23 Santee 42.49 Devil's Nest Airstrip 42.49 Reamsville 39.55 The Pits 42.11 Edson Quarry 39.09 Rhinoceros Hill 39.07 Ganson Farm 38.26 Bemis 38.52 Optima 36.45 Gravel Pits 36.08 Channing Area 35.41 Coffee Ranch Quarry 35.44 General Goodnight Fauna 34.57 Axtel 34.55 Christian Ranch 34.57 Currie Ranch 35.02 Smart Ranch 33.31 J. C. Strange Gravel Quarry 33.31 Long Ranch 33.31

Long -98.33 -100.04 -99.46 -98.08 -99.47 -99.49 -104.43 -104.43 -99.32 -99.32 -99.32 -99.32 -99.25 -101.22 -99.00 -101.53 -101.43 -101.40 -98.39 -98.07 -97.51 -97.43 -98.55 -103.46 -101.30 -101.30 -97.28 -99.30 -101.22 -99.57 -102.19 -100.31 -101.11 -101.42 -101.29 -101.45 -101.38 -101.39 -101.39

State NE NE NE NE NE NE WY WY KS KS KS KS KS OK KS NE NE NE NE NE NE NE KS NE KS KS KS KS OK OK TX TX TX TX TX TX TX TX TX

County Webster Brown Brown Knox Brown Brown Laramie Laramie Ellis Ellis Ellis Ellis Phillips Texas Ellis Keith Keith Keith Holt Antelope Knox Knox Smith Sioux Sherman Wallace McPherson Ellis Texas Ellis Hartley Hemphill Armstrong Randall Armstrong Randall Lubbock Lubbock Lubbock

Formation Valentine Valentine Valentine Valentine Valentine Valentine Ash Hollow Ash Hollow Ogallala Group Ogallala Group Ogallala Group Ogallala Group Valentine Ogallala Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Snake Creek Ogallala Ogallala Delmore Ogallala Ogallala Ogallala Ogallala Hemphill Beds Goodnight Beds Goodnight Beds Goodnight Beds Goodnight Beds Bridwell Bridwell Bridwell

Age ECLA ECLA ECLA LBAR LBAR LBAR BACL BACL CLAR CLAR CLAR CLAR BACL ELHP HMP EEHP EEHP EEHP ELHP ELHP LLHP LLHP LEHP LEHP ELHP ELHP EEHP LEHP ELHP LLHP LHMP ELHP ELHP LLHP LLHP LLHP LLHP ELHP LLHP

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late

131


Genus Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion

Species eurystyle eurystyle eurystyle leptode leptode leptode leptode leptode leptode leptode leptode leptode leptode trampasense trampasense trampasense trampasense trampasense trampasense trampasense trampasense trampasense trampasense trampasense trampasense affine affine affine affine affine affine affine affine affine affine affine affine affine affine

Site Name Bridwell Formation (TMM 42442) Rentfro Pit 1 Anderson Quarry #2 Greenwood Canyon Quarry Oshkosh Potter Amebelodon fricki Quarry Minium Quarry Capps, George Neu, and Pratt Pitts Arnett Coffee Ranch Quarry General Sebits Ranch Box T Gallup Gulch Kepler Quarry Machaerodus Quarry Xmas Quarry East Kat Quarry Hans Johnson Quarry Leptarctus Quarry Line Kat Quarry Quarter Line Kat Quarry Trailside Kat Quarry Jack Swayze Quarry Arens Quarry Dawson no. 1 Dawson no. 2 Porcupine Butte Poison Ivy Quarry Gallup Gulch Clayton Quarry Beads Creek no. 1 Big Spring Canyon Burge Quarry Gordon Creek Quarry Crazy Locality Fence Line Locality Sherman Ranch Locality Fatigue Locality

Lat 33.40 35.52 39.44 41.27 41.20 41.06 40.23 39.24 36.05 36.07 35.44 36.05 36.14 42.49 41.40 42.53 42.53 42.53 42.53 42.53 42.53 42.53 42.53 37.22 39.47 43.00 43.00 43.18 42.25 42.49 42.41 43.00 43.07 42.45 42.46 42.41 42.55 42.49 42.43

Long -101.12 -102.33 -100.41 -103.03 -102.23 -103.13 -100.15 -100.08 -99.55 -99.57 -100.31 -100.00 -100.05 -101.44 -102.48 -100.14 -100.14 -100.13 -100.13 -100.15 -100.14 -100.14 -100.15 -99.47 -99.54 -100.00 -100.00 -102.32 -98.09 -101.44 -99.55 -100.00 -101.56 -100.49 -100.39 -100.51 -100.23 -100.06 -100.50

State TX TX KS NE NE NE NE KS OK OK TX TX TX NE NE NE NE NE NE NE NE NE NE KS KS SD SD SD NE NE NE SD SD NE NE NE NE NE NE

County Lubbock Hartley Decatur Morrill Garden Cheyenne Frontier Graham Ellis Ellis Hemphill Lipscomb Lipscomb Cherry Morrill Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Clark Norton Todd Todd Shannon Antelope Cherry Brown Todd Bennett Cherry Cherry Cherry Cherry Keya Paha Cherry

Age ELHP ELHP EEHP LEHP LEHP LEHP LEHP LEHP EEHP EEHP ELHP EEHP LEHP CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR EEHP EEHP

CLAR CLAR CLAR CLAR CLAR ECLA ECLA ECLA ECLA ECLA ECLA

Formation Bridwell Ogallala Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ogallala Ogallala Hemphill Beds Ogallala Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ogallala Ogallala

Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Valentine Valentine Valentine Valentine Valentine Valentine

Time Slice Late Late Late Late Late Late Late Late Late Late Late Late Late Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Late Late Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

132


Genus Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Neohipparion Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus

Species affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine affine republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus republicanus

Site Name Kepler Quarry Niobrara River Valley Penny Creek Wt-11 Penny Creek Wt-12 Penny Creek Wt-13 Kilpatrick Quarry Hesperopithecus Site Olcott Hill June Quarry Paleo Quarry Quinn Mastodon Quarry Quinn Rhino Quarries 1 and 2 Leptarctus Quarry Eli Ash Pit 4 or 5 miles W of Rosebud Agency Wakeeney (KU Loc. 29) MacAdams Quarry Noble Ranch Grant Quarry Rowe-Lewis Quarry 1 Rowe-Lewis Quarry 7 Sand Canyon (Colorado) Yoos Quarry Norden Bridge Quarry Carrot Top Quarry Rosetta Stone Locality Achilles Quarry Welke Locality Lost Chance Locality Norden Damsite Locality Penbrook Quarry Egelhoff Quarry Quarry Without a Name Crookston Bridge Quarry Railway Quarry A Myers Farm Hottell Ranch Main Quarry Hottell Ranch Horse Quarry Immense Journey Quarry

Lat 41.40 42.54 40.01 40.01 40.00 42.10 42.10 42.10 42.38 42.28 42.41 42.41 42.53 42.53 43.13 39.05 35.04 35.02 35.04 35.04 35.06 40.59 39.42 42.47 42.47 42.46 42.47 42.46 42.46 42.47 42.51 42.48 42.47 42.46 42.50 40.01 41.32 41.32 41.32

Long -102.48 -100.29 -98.33 -98.33 -98.33 -103.43 -103.43 -103.43 -100.04 -102.42 -99.55 -99.55 -100.15 -101.27 -100.56 -99.45 -100.54 -100.51 -100.54 -100.43 -100.43 -103.28 -100.50 -100.02 -100.04 -100.05 -100.04 -100.06 -100.07 -100.01 -100.13 -100.03 -100.02 -100.47 -100.31 -98.32 -103.56 -103.56 -103.56

State NE NE NE NE NE NE NE NE NE NE NE NE NE NE SD KS TX TX TX TX TX CO KS NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE

County Morrill Cherry Webster Webster Webster Sioux Sioux Sioux Brown Sheridan Brown Brown Cherry Cherry Todd Trego Donley Donley Donley Donley Donley Logan Rawlins Brown Brown Brown Brown Brown Brown Brown Cherry Keya Paha Keya Paha Cherry Cherry Webster Banner Banner Banner

Formation Ash Hollow Ash Hollow Valentine Valentine Valentine Snake Creek Snake Creek Snake Creek Valentine Valentine Valentine Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ogallala Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Ogallala Group Ogallala Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine

Age CLAR CLAR ECLA ECLA ECLA CLAR CLAR CLAR ECLA ECLA ECLA CLAR CLAR CLAR CLAR MCLA MCLA MCLA MCLA MCLA MCLA LBAR CLAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR LBAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

133


Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus

Merychippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus

Genus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus

Species republicanus republicanus republicanus republicanus republicanus coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense coloradense Middle coloradense gidleyi gidleyi gidleyi gidleyi gidleyi gidleyi gidleyi Late gidleyi gidleyi supremus supremus supremus supremus supremus supremus supremus supremus Amebelodon fricki Quarry Wray Lucht Quarry Kilpatrick Quarry June Quarry Hollow Horn Bear Quarry Gallup Gulch East Clayton Quarry Clayton Quarry Bear Creek Quarry

Uhl Pit Xmas Quarry West Line Kat Quarry Jack Swayze Quarry Long Island Quarry Leptarctus Quarry East Kat Quarry Box T

Site Name Annie's Geese Cross Hazard Homestead Quarry Jamber Quarry Forked Hills of Hayden Vim-Peetz II Trail Creek Quarry Sherman Ranch Locality Quinn Mastodon Quarry Penny Creek Wt-11 Penny Creek Wt-12 Penny Creek Wt-13 Gordon Creek Quarry Fence Line Locality Burge Quarry West Valentine Quarry Boulder Quarry Sand Canyon (Colorado) Pawnee Buttes

40.23 40.04 42.40 42.10 42.38 43.09 42.49 42.41 42.41 42.53

40.47 42.53 42.53 37.22 39.54 42.53 42.53 36.14

Lat 42.49 40.03 42.51 42.55 40.59 41.25 42.49 42.41 40.01 40.01 40.00 42.46 42.55 42.45 42.50 42.10 40.59 40.49

-100.15 -102.13 -99.46 -103.43 -100.04 -101.06 -101.44 -99.55 -99.55 -101.23

-103.56 -100.14 -100.14 -99.47 -99.31 -100.15 -100.13 -100.05

Long -97.38 -100.53 -98.46 -99.01 -103.30 -104.43 -100.06 -99.55 -98.33 -98.33 -98.33 -100.39 -100.23 -100.49 -100.31 -103.43 -103.28 -103.58

NE CO NE NE NE SD NE NE NE NE

CO NE NE KS KS NE NE TX

State NE NE NE NE CO WY NE NE NE NE NE NE NE NE NE NE CO CO

Frontier Yuma Brown Sioux Brown Todd Cherry Brown Brown Cherry

Weld Cherry Cherry Clark Phillips Cherry Cherry Lipscomb

County Knox Hitchcock Boyd Boyd Logan Laramie Keya Paha Brown Webster Webster Webster Cherry Cherry Cherry Cherry Sioux Logan Weld

Ash Hollow Ogallala Group Valentine Snake Creek Valentine Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow

LEHP LEHP ECLA CLAR ECLA CLAR CLAR CLAR CLAR CLAR

Ogallala Group LBAR Ash Hollow CLAR Ash Hollow CLAR Ogallala EEHP Ash Hollow EEHP Ash Hollow CLAR Ash Hollow CLAR Ogallala (Hemphill Beds)

Formation Age Valentine LBAR Valentine LBAR Valentine LBAR Valentine LBAR Ogallala Group LBAR Ash Hollow BACL Valentine ECLA Valentine ECLA Valentine ECLA Valentine ECLA Valentine ECLA Valentine ECLA Valentine ECLA Valentine ECLA Valentine LBAR Olcott EBAR Ogallala Group LBAR Pawnee Creek/Ogallala Group

Late Late Middle Middle Middle Middle Middle Middle Middle Middle

Middle Middle Middle Late Late Middle Middle LEHP

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Early Middle LBAR

134


Genus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus Protohippus

Species supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus supremus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus perditus

Site Name Canyon of Little White River Burge Quarry Burge B Quarry Gordon Creek Quarry Crazy Locality Fence Line Locality Fatigue Locality Little Beaver B North Rim Locality Crooked Creek Locality West Coon Creek Locality Buzzard Feather Locality Logan Quarry Bluejay Quarry Penny Creek Wt-11 Penny Creek Wt-12 Midway Quarry Charles Risley Ranch MacAdams Quarry Adam Risley Ranch Spoon Butte Penny Creek Wt-11 Penny Creek Wt-12 Hottell Ranch Horse Quarry Forked Hills of Hayden Fairfield Falls Elliott Norden Bridge Quarry Carrot Top Quarry Rosetta Stone Locality Crookston Bridge Quarry Railway Quarry A Annie's Geese Cross Hazard Homestead Quarry Jamber Quarry Niobrara River Valley Verdigre Quarry

Lat 43.16 42.45 42.44 42.46 42.41 42.55 42.43 42.55 42.55 42.55 42.55 42.48 42.50 42.23 40.01 40.01 42.53 35.04 35.04 35.03 42.20 40.01 40.01 41.32 42.55 42.46 42.36 42.47 42.47 42.46 42.46 42.50 42.49 40.03 42.51 42.54 42.29

Long -100.55 -100.49 -100.49 -100.39 -100.51 -100.23 -100.50 -100.24 -100.27 -100.24 -100.28 -100.03 -100.02 -98.06 -98.33 -98.33 -100.14 -100.52 -100.54 -100.52 -104.04 -98.33 -98.33 -103.56 -99.01 -100.06 -99.41 -100.02 -100.04 -100.05 -100.47 -100.31 -97.38 -100.53 -98.46 -100.29 -98.08

State SD NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE TX TX TX WY NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE

County Todd Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Keya Paha Keya Paha Antelope Webster Webster Cherry Donley Donley Donley Goshen Webster Webster Banner Boyd Brown Brown Brown Brown Brown Cherry Cherry Knox Hitchcock Boyd Cherry Knox

Formation Ash Hollow Valentine Valentine Valentine Valentine Valentine Valentine Ash Hollow Ash Hollow Ash Hollow Ash Hollow Valentine Valentine Ash Hollow Valentine Valentine Valentine Clarendon Beds Clarendon Beds Clarendon Beds Lay Ranch Beds Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine Valentine

Age CLAR ECLA ECLA ECLA ECLA ECLA ECLA CLAR CLAR CLAR CLAR ECLA LBAR CLAR ECLA ECLA ECLA MCLA MCLA MCLA LLAK ECLA ECLA LBAR LBAR LBAR LBAR LBAR LBAR BACL LBAR LBAR LBAR LBAR LBAR LBAR LBAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Early Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

135


Genus Protohippus Protohippus Protohippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus

Species perditus perditus perditus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus regulus proplacidus proplacidus proplacidus proplacidus proplacidus placidus placidus placidus placidus placidus placidus

Site Name Lat Devil's Gulch Horse Quarry 42.42 Sappa Creek (Rawlins County) 39.42 Republican River Beds (Phillips County) 39.59 Railway Quarry A 42.50 Quinn Mastodon Quarry 42.41 Lucht Quarry 42.40 Leptarctus Quarry 42.53 Kennesaw I 40.59 June Quarry 42.38 Devil's Gulch Horse Quarry 42.42 Penny Creek Wt-11 40.01 Penny Creek Wt-12 40.01 Penny Creek Wt-13 40.00 Penny Creek Wt-15B 40.01 Gretna 39.50 Keller 39.04 Beaver Quarry 36.45 Exell 35.38 Shannon Ranch 35.04 Charles Risley Ranch 35.04 MacAdams Quarry 35.04 Grant Quarry 35.04 General Rowe-Lewis Ranch Quarries 35.06 General Clarendon Beds 35.04 Norden Bridge Quarry 42.47 Carrot Top Quarry 42.47 Devil's Gulch Horse Quarry 42.42 Sand Canyon (Colorado) 40.59 General Vim-Peetz Locality 40.59 Mission Fauna 43.24 Hollow Horn Bear Quarry 43.09 Gallup Gulch 42.49 Forked Hills of Hayden 42.55 East Clayton Quarry 42.41 Clayton Quarry 42.41

Long -99.47 -100.58 -99.25 -100.31 -99.55 -99.46 -100.15 -103.29 -100.04 -99.47 -98.33 -98.33 -98.33 -98.32 -99.12 -99.33 -100.14 -101.54 -100.54 -100.52 -100.54 -100.54 -100.42 -100.48 -100.02 -100.04 -99.47 -103.28 -103.31 -100.36 -101.06 -101.44 -99.01 -99.55 -99.55

State NE KS KS NE NE NE NE CO NE NE NE NE NE NE KS KS OK TX TX TX TX TX TX TX NE NE NE CO CO SD SD NE NE NE NE

County Brown Rawlins Phillips Cherry Brown Brown Cherry Logan Brown Brown Webster Webster Webster Webster Phillips Ellis Beaver Moore Donley Donley Donley Donley Donley Donley Brown Brown Brown Logan Logan Mellette Todd Cherry Boyd Brown Brown

Formation Valentine Ogallala Valentine Valentine Valentine Valentine Ash Hollow Ogallala Group Valentine Valentine Valentine Valentine Valentine Valentine Ogallala Group Ogallala Group Ogallala Ogallala Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Valentine Valentine Valentine Ogallala Group Ogallala Group Ash Hollow Ash Hollow Ash Hollow Valentine Ash Hollow Ash Hollow

Age LBAR CLHP BACL LBAR ECLA ECLA CLAR LBAR ECLA LBAR ECLA ECLA ECLA ECLA CLAR MCLA MCLA CLAR MCLA MCLA MCLA MCLA MCLA MCLA LBAR LBAR LBAR LBAR LBAR CLAR CLAR CLAR LBAR CLAR CLAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

136


Genus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus

Species placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus placidus cerasinus cerasinus cerasinus cerasinus cerasinus cerasinus cerasinus cerasinus cerasinus cerasinus martini martini martini martini martini martini martini martini

Site Name Bear Creek Quarry Oak Creek Little Beaver B Crooked Creek Locality Railway Quarry A Myers Farm Hottell Ranch Horse Quarry Poison Ivy Quarry Chokecherry Quarry Annie's Geese Cross Hazard Homestead Quarry Jamber Quarry Niobrara River Valley Verdigre Quarry Near Ainsworth Exell Shannon Ranch Charles Risley Ranch MacAdams Quarry Grant Quarry General Clarendon Beds Machaerodus Quarry Hans Johnson Quarry Wade Quarry Xmas Quarry Connection Kat Quarry East Kat Quarry Kat Quarry Leptarctus Quarry Quarter Line Kat Quarry West Line Kat Quarry Wakeeney (KU Loc. 29) Wade Quarry Poison Ivy Quarry Lucht Quarry Little Beaver B Horse Thief Canyon No. 2 Hollow Horn Bear Quarry Gallup Gulch

Lat 42.53 43.18 42.55 42.55 42.50 40.01 41.32 42.25 42.28 42.49 40.03 42.51 42.54 42.29 42.33 35.38 35.04 35.04 35.04 35.04 35.04 42.53 42.53 42.43 42.53 42.53 42.53 42.53 42.53 42.53 42.53 39.05 42.43 42.25 42.40 42.55 42.41 43.09 42.49

Long -101.23 -100.26 -100.24 -100.24 -100.31 -98.32 -103.56 -98.09 -98.05 -97.38 -100.53 -98.46 -100.29 -98.08 -99.51 -101.54 -100.54 -100.52 -100.54 -100.54 -100.48 -100.14 -100.13 -100.50 -100.14 -100.15 -100.13 -100.14 -100.15 -100.14 -100.14 -99.45 -100.50 -98.09 -99.46 -100.24 -99.58 -101.06 -101.44

State NE SD NE NE NE NE NE NE NE NE NE NE NE NE NE TX TX TX TX TX TX NE NE NE NE NE NE NE NE NE NE KS NE NE NE NE NE SD NE

County Cherry Todd Cherry Cherry Cherry Webster Banner Antelope Knox Knox Hitchcock Boyd Cherry Knox Brown Moore Donley Donley Donley Donley Donley Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Cherry Trego Cherry Antelope Brown Cherry Brown Todd Cherry

Formation Ash Hollow Oak Creek? Ash Hollow Ash Hollow Valentine Valentine Valentine Ash Hollow Ash Hollow Valentine Valentine Valentine Valentine Valentine Ash Hollow Ogallala Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Clarendon Beds Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ogallala Ash Hollow Ash Hollow Valentine Ash Hollow Ash Hollow Ash Hollow Ash Hollow

Age CLAR CLAR CLAR CLAR LBAR LBAR LBAR CLAR CLAR LBAR LBAR LBAR LBAR LBAR CLAR CLAR MCLA MCLA MCLA MCLA MCLA CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR MCLA CLAR CLAR ECLA CLAR CLAR CLAR CLAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle

137


Genus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Calippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Acritohippus Acritohippus Acritohippus Acritohippus Acritohippus Acritohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus

Species martini martini martini martini martini martini martini martini martini martini martini martini martini martini martini martini martini martini intermontanus intermontanus intermontanus sejunctus sejunctus sejunctus sejunctus sejunctus isonesus isonesus tertius tertius tertius tertius nobilis nobilis nobilis nobilis nobilis nobilis nobilis

Site Name East Clayton Quarry Dawson no. 3 Clayton Quarry Chokecherry Quarry Bear Creek Quarry Wolf Creek V5324 Wolf Creek V5329 Wolf Creek V5335 Big Spring Canyon Mission Fauna Whisenhunt Quarry Beaver Quarry Cragin Quarry Charles Risley Ranch MacAdams Quarry Grant Quarry General Rowe-Lewis Ranch Quarries Wild Horse Creek #1 East Sand Quarry Echo Quarry Mill Quarry Horse and Mastodon Quarry 5 miles E of Kremmling Eubanks Pawnee Buttes General Keota Fauna Middle of the Road Quarry Foley Quarry Greenside Quarry Thomson Quarry Merychippus Draw General Red Valley Member Oshkosh Lemoyne Quarry Ogallala Beach Feldt Ranch Long Island Quarry Capps, George Neu, and Pratt Pitts Arnett

Lat 42.41 43.00 42.41 42.28 42.53 43.00 43.01 43.00 43.07 43.24 36.45 36.45 36.45 35.04 35.04 35.04 35.06 35.47 42.09 42.10 42.11 40.49 40.03 40.52 40.49 40.49 42.24 42.24 42.10 42.10 42.11 42.24 41.20 41.17 41.08 41.08 39.54 36.05 36.07

Long -99.55 -100.00 -99.55 -98.05 -101.23 -102.24 -102.24 -102.25 -101.56 -100.36 -100.02 -100.14 -100.21 -100.52 -100.54 -100.54 -100.42 -99.38 -103.43 -103.44 -103.44 -104.04 -106.16 -103.55 -103.58 -104.04 -103.02 -103.02 -103.44 -103.45 -103.47 -103.01 -102.23 -101.53 -101.43 -101.40 -99.31 -99.55 -99.57

State NE SD NE NE NE SD SD SD SD SD OK OK OK TX TX TX TX OK NE NE NE CO CO CO CO CO NE NE NE NE NE NE NE NE NE NE KS OK OK

County Formation Brown Ash Hollow Todd Brown Ash Hollow Knox Ash Hollow Cherry Ash Hollow Shannon Ash Hollow Shannon Ash Hollow Shannon Ash Hollow Bennett Ash Hollow Mellette Ash Hollow Beaver Ogallala Beaver Ogallala Beaver Ogallala Donley Clarendon Beds Donley Clarendon Beds Donley Clarendon Beds Donley Clarendon Beds Roger Mills Ogallala Sioux Olcott Sioux Olcott Sioux Olcott Weld Pawnee Creek Grand Troublesome Weld Pawnee Creek Weld Pawnee Creek Weld Pawnee Creek Box Butte Box Butte Box Butte Box Butte Sioux Sheep Creek Sioux Sheep Creek Sioux Sheep Creek Box Butte/Dawes Box Butte Garden Ash Hollow Keith Ash Hollow Keith Ash Hollow Keith Ash Hollow Phillips Ash Hollow Ellis Ogallala Ellis Ogallala CLAR CLAR CLAR CLAR CLAR CLAR CLAR CLAR MCLA MCLA MCLA MCLA MCLA MCLA MCLA CLHE EBAR EBAR EBAR LBAR HEBA LBAR LBAR LBAR LHMF LHMF LHMF LHMF LHMF LHMF LEHP EEHP EEHP EEHP EEHP EEHP EEHP

Age CLAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Early Early Early Middle Early Early Middle Middle Early Early Early Early Early Early Late Late Late Late Late Late Late

138


Genus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus

Species nobilis nobilis nobilis pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix pernix

Site Name Sebits Ranch Locality 24-A Sebits Ranch Locality 24-B Box T Wolf Creek V526 Wolf Creek V527 Wolf Creek V529 Wolf Creek V5324 Wolf Creek V5325 Wolf Creek V5326 Wolf Creek V5328 Wolf Creek V5332 Turtle Butte (West Gap) Big Spring Canyon Big Spring Canyon Big Spring Canyon Big Spring Canyon Big Spring Canyon Oak Creek McGinley's Stadium Serendipity Quarry Bluejay Quarry Kepler Quarry North Shore Lonergan Creek Poison Ivy Quarry Chokecherry Quarry Charles Risley Ranch Grant Quarry Lower Couch Formation (TMM 42433) Lower Couch Formation (TMM 42443) Upper Couch Formation (TMM 947) Upper Couch Formation (TMM 963) Upper Couch Formation (TMM 42448) Durham

Lat 36.05 36.05 36.14 43.00 43.00 43.00 43.00 43.00 42.59 43.00 43.00 43.04 43.07 43.07 43.07 43.07 43.07 43.18 42.45 42.49 42.23 41.40 41.16 41.16 42.25 42.28 35.04 35.04 33.40 33.41 33.39 33.41 33.41 35.00

Long -100.00 -100.00 -100.05 -102.24 -102.23 -102.24 -102.24 -102.24 -102.23 -102.24 -102.27 -99.50 -101.56 -101.56 -101.56 -101.56 -101.56 -100.26 -100.09 -100.04 -98.06 -102.48 -101.48 -101.48 -98.09 -98.05 -100.52 -100.54 -101.07 -101.09 -101.07 -101.10 -101.10 -99.00

State TX TX TX SD SD SD SD SD NE SD SD SD SD SD SD SD SD SD NE NE NE NE NE NE NE NE TX TX TX TX TX TX TX OK

County Lipscomb Lipscomb Lipscomb Shannon Shannon Shannon Shannon Shannon Sheridan Shannon Shannon Tripp Bennett Bennett Bennett Bennett Bennett Todd Brown Keya Paha Antelope Morrill Keith Keith Antelope Knox Donley Donley Crosby Crosby Crosby Crosby Crosby Roger Mills

Formation Ogallala Ogallala Ogallala Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Valentine Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Oak Creek? Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Ash Hollow Clarendon Beds Clarendon Beds Couch Couch Couch Couch Couch

Age Time Slice EEHP Late EEHp Late LEHP Late CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle ECLA Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle CLAR Middle MCLA Middle MCLA Middle MCLA Middle MCLA Middle MCLA Middle MCLA Middle MCLA Middle ECLA/EHEMPH Middle

139


Pliohippus Pliohippus Pliohippus Pliohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus

Pliohippus Pliohippus Pliohippus

Genus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus Pliohippus

Species pernix pernix pernix pernix pernix pernix pernix pernix pernix fossulatus fossulatus fossulatus fossulatus mirabilis mirabilis mirabilis mirabilis Middle mirabilis mirabilis mirabilis Middle mirabilis mirabilis mirabilis mirabilis stockii stockii stockii stockii stockii stockii stockii ansae ansae ansae Horse and Mastodon Quarry General Vim-Peetz Locality Forked Hills of Hayden Nenzel Quarry Gravel Pits Axtel Christian Ranch Currie Ranch Rentfro Pit 1 Smart Ranch Rentfro Pit 1 Oshkosh Edson Quarry Lost Quarry

Devil's Gulch Horse Quarry Sand Canyon (Colorado) Pawnee Buttes

Site Name Soldier Creek no. 6 Soldier Creek no. 10 Soldier Creek no. 17 Spirit Mound Bear Creek Quarry Burge Quarry Kilpatrick Quarry Little Beaver B Midway Quarry Exell MacAdams Quarry Dilli 1938 Pliohippus fossulatus skull site Railway Quarry A Hottell Ranch Horse Quarry Hazard Homestead Quarry Niobrara River Valley

40.49 40.59 42.55 42.48 36.08 34.55 34.57 35.02 35.52 33.31 35.52 41.20 39.09 38.47

42.42 40.59 40.49

Lat 43.00 43.00 43.00 43.00 42.53 42.45 42.10 42.55 42.53 35.38 35.04 35.04 35.10 42.50 41.32 40.03 42.54

-104.04 -103.31 -99.01 -101.08 -99.57 -101.42 -101.29 -101.45 -102.33 -101.38 -102.33 -102.23 -101.30 -101.29

-99.47 -103.28 -103.58

Long -100.00 -100.00 -100.00 -100.00 -101.23 -100.49 -103.43 -100.24 -100.14 -101.54 -100.54 -100.52 -100.43 -100.31 -103.56 -100.53 -100.29

CO CO NE NE OK TX TX TX TX TX TX NE KS KS

NE CO CO

State SD SD SD SD NE NE NE NE NE TX TX TX TX NE NE NE NE

Weld Logan Boyd Cherry Ellis Randall Armstrong Randall Hartley Lubbock Hartley Garden Sherman Wallace

Brown Logan Weld

CLAR ECLA CLAR CLAR ECLA CLAR MCLA MCLA MCLA LBAR LBAR LBAR Valentine

Age

Pawnee Creek Ogallala Group Valentine Valentine Ogallala Goodnight Beds Goodnight Beds Goodnight Beds Ogallala Bridwell Ogallala Ash Hollow Ogallala Ogallala

LBAR LBAR LBAR LBAR LLHP LLHP LLHP LLHP ELHP LLHP ELHP LEHP ELHP ELHP

Valentine LBAR Ogallala Group LBAR Pawnee Creek/Ogallala Group

County Formation Todd Todd Todd Todd Cherry Ash Hollow Cherry Valentine Sioux Snake Creek Cherry Ash Hollow Cherry Valentine Moore Ogallala Donley Clarendon Beds Donley Clarendon Beds Donley Clarendon Beds Cherry Valentine Banner Valentine Hitchcock Valentine Cherry, Keya Paha, Boyd

Middle Middle Middle Middle Late Late Late Late Late Late Late Late Late Late

Middle Middle LBAR

Time Slice Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle Middle LBAR

140


Genus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Astrohippus Hippidion Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Dinohippus Merychippus Merychippus

mexicanus mexicanus mexicanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus leidyanus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus interpolatus primus primus

Species ansae ansae ansae ansae ansae ansae ansae

Site Name Coffee Ranch Quarry General Goodnight Fauna Smart Ranch J. C. Strange Gravel Quarry Wallace Ranch Johnson's Ranch West of Johnson's Ranch V. V. Parker Pits Axtel Christian Ranch Currie Ranch Uptegrove Quarry Honey Creek Mailbox Amebelodon fricki Quarry Aphelops Quarries Aphelops Quarries The Pits Pliohippus Draw Coffee Ranch Quarry Optima Edson Quarry Edson Quarry Lost Quarry Found Quarry Rhinoceros Hill Parcell Ranch Coffee Ranch Quarry General Goodnight Fauna J. C. Strange Gravel Quarry J. C. Strange Gravel Quarry Long Ranch Long Ranch Bridwell Formation (TMM 42441) Johnson's Ranch Rentfro Pit 1 Wray 10 mi. NE of McLean Greenside Quarry Thomson Quarry

Lat 35.44 34.57 33.31 33.31 33.31 33.31 33.31 36.15 34.55 34.57 35.02 41.15 42.41 42.23 40.23 42.12 42.12 42.11 42.11 35.44 36.45 39.09 39.09 38.47 38.47 39.07 35.59 35.44 34.57 33.31 33.31 33.31 33.31 33.40 33.31 35.52 40.04 35.21 42.10 42.10

Long -100.31 -101.11 -101.38 -101.39 -101.38 -101.39 -101.39 -100.02 -101.42 -101.29 -101.45 -102.54 -98.39 -98.07 -100.15 -103.47 -103.47 -103.46 -103.46 -100.31 -101.22 -101.30 -101.30 -101.29 -101.29 -101.30 -100.35 -100.31 -101.11 -101.39 -101.39 -101.39 -101.39 -101.11 -101.39 -102.33 -102.13 -100.33 -103.44 -103.45

State TX TX TX TX TX TX TX TX TX TX TX NE NE NE NE NE NE NE NE TX OK KS KS KS KS KS TX TX TX TX TX TX TX TX TX TX CO TX NE NE

County Hemphill Armstrong Lubbock Lubbock Lubbock Lubbock Lubbock Lipscomb Randall Armstrong Randall Cheyenne Holt Antelope Frontier Sioux Sioux Sioux Sioux Hemphill Texas Sherman Sherman Wallace Wallace Wallace Roberts Hemphill Armstrong Lubbock Lubbock Lubbock Lubbock Lubbock Lubbock Hartley Yuma Gray Sioux Sioux

Formation Hemphill Beds Goodnight Beds Bridwell Bridwell Bridwell Bridwell Bridwell Ogallala Goodnight Beds Goodnight Beds Goodnight Beds Ash Hollow Ash Hollow Ash Hollow Ash Hollow Snake Creek Snake Creek Snake Creek Snake Creek Hemphill Beds Ogallala Ogallala Ogallala Ogallala Ogallala Ogallala Ogallala Hemphill Beds Goodnight Beds Bridwell Bridwell Bridwell Bridwell Bridwell Bridwell Ogallala Ogallala Group Ogallala? Sheep Creek Sheep Creek

Age ELHP ELHP LLHP ELHP LLHP LLHP LLHP EEHP LLHP LLHP LLHP ELHP ELHP ELHP LEHP LEHP LEHP LEHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP ELHP LLHP LLHP ELHP LLHP ELHP LEHP HEMP LHMF LHMF

Time Slice Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Late Early Early

141


Genus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Merychippus Parahippus Parahippus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus Equus

Species primus primus primus primus primus primus primus primus primus primus leonensis leonensis simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens simplicidens

Site Name Hilltop Quarry Thistle Quarry Stonehouse Draw 23 mi. S of Agate Foley Quarry Dry Creek Prospect D General Red Valley Member Companion Quarry Split Rock, UCMP V-77151 Devil's Gate (UCMP V-77155) Cottonwood Creek Quarry Cross Mountain Donnelly Ranch Angell Member Deer Park Sanders Seger Gravel Pit White Rock Wilson Loc. White Rock Hibbard Loc. White Rock Middle Loc. White Rock Hanel Sandpit Loc White Rock Railroad Loc White Rock Millen Sandpit Loc. Broadwater Locality A Lisco Locality C Meade's Quarry 9 Marmot Quarry Carter Quarry Cita Canyon Channing Hereford Dump Beck Ranch Martin Ranch (Lower)

Lat 42.10 42.10 42.10 42.10 42.24 42.24 42.24 42.08 42.27 42.26 42.32 40.26 37.16 37.41 37.18 37.28 37.22 39.91 39.91 39.91 39.88 39.84 0.00 41.60 41.52 33.78 33.79 33.78 34.96 35.68 34.85 32.72 34.51

Long -103.44 -103.44 -103.45 -103.45 -103.02 -103.01 -103.01 -103.49 -107.32 -107.26 -103.08 -108.17 -103.51 -99.88 -100.46 -100.40 -100.48 -97.87 -97.87 -97.87 -97.53 -97.53 -97.79 -102.74 -102.53 -101.26 -101.26 -101.26 -101.89 -102.48 -102.34 -100.74 -101.43

State NE NE NE NE NE NE NE NE WY WY NE CO CO KS KS KS KS KS KS KS KS KS KS NE NE TX TX TX TX TX TX TX TX

County Formation Sioux Sheep Creek Sioux Sheep Creek Sioux Sheep Creek Sioux Sheep Creek Box Butte Box Butte Box Butte Box Butte Box Butte/Dawes Box Butte Sioux Sheep Creek Natrona Split Rock Natrona Split Rock Dawes Runningwater Moffat Browns Park Las Animas Meade Ballard Meade Ballard Meade Ballard Meade Crooked Creek Republc Republc Republc Republc Republc Republc Morrill Garden Crosby Blanco Crosby Blanco Crosby Blanco Randall Hartley Deaf Smith Scurry Briscoe Tule

Age Time Slice LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early LHMF Early EHMF Early HMF Early BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late BLANCAN Late IRV Late

142


143 APPENDIX D: ORIGINAL ENVIRONMENTAL DATA Geographic location information for each environmental data point with the original value of the environmental variable and reference. The age and NALMA for each site is included. Appendix D1: Stable Isotopes AppendixD2: Mean Annual Percipitation (MAP) AppendixD3: Mollic Horizon AppendixD4: Vegetation AppendixD5: Crocodile Presence/Absense

144

APPENDIX D1: STABLE ISOTOPES Location Name

Latitude

Longitude

Age

Time Slice

NALMA

δ13C

% C4

Reference

Breakneck Hill

41.60

-102.80

23.00

Early

Arikareean

-7.20*

20

Fox and Koch 2003

Reference section 1 (Fox and Koch, 2003)

42.40

-103.10

17.50

Early

Hemingfordian

-7.54*

18

Fox and Koch 2003

Refence section 2 (Fox and Koch, 2003)

42.40

-103.30

17.50

Early

Hemingfordian

-6.95*

21

Fox and Koch 2003

42.10

-103.44

15.00

Early

Barstovian

-8.50†

17

Wang et al. 1994; Damuth et al. 2002; Passey et al. 2002

West Surface Quarry

42.09

-103.43

15.00

Early

Barstovian

-8.50†

17

Wang et al. 1994; Passey et al. 2002

Thompson Quarry

42.19

-103.75

17.50

Early

Hemingfordian

-9.15†

14

Damuth et al. 2002; Passey et al. 2002

East Sand Quarry

42.16

-103.73

15.50

Early

Barstovian

-7.00†

27

Clouthier 1994

Long Quarry

42.19

-103.73

18.00

Early

Hemingfordian

0†

0

Clouthier 1994

Cottonwood Creek Quarry

42.55

-103.14

18.50

Early

Hemingfordian

0†

0

Clouthier 1994

Brown County

42.47

-99.94

3.30

Early

Hemingfordian

-7.80†

31

Wang et al. 1994

Hill Top Quarry

42.10

-103.44

17.00

Early

Hemingfordian

-9.90†

9

Wang et al. 1994

Thomson Quarry

42.10

-103.45

17.50

Early

Hemingfordian

-10.60†

4

Wang et al. 1994

Norden Bridge Quarry

42.80

-100.00

14.30

Middle

Barstovian

-6.60*

25

Damuth et al. 2002; Fox and Koch 2003


42.80

-100.00

14.30

Middle

Barstovian

-8.93†

17

Passey et al. 2002

Egelhoff Quarry

42.80

-100.10

14.30

Middle

Barstovian

-6.05*

28

Fox and Koch 2003

Ashfall Fossil Beds State Historical Park A

42.40

-98.20

13.70

Middle

Barstovian

-8.63*

12

Fox and Koch 2003

Ashfall Fossil Beds State Historical Park B

42.20

-98.20

13.70

Middle

Barstovian

-8.00*

15

Fox and Koch 2003

Yellowhouse Canyon A1

33.50

-101.60

13.05

Middle

Barstovian

-5.99*

29

Fox and Koch 2003

Yellowhouse Canyon B1

33.50

-101.60

13.05

Middle

Barstovian

-5.82*

30

Fox and Koch 2003

Echo Quarry

145 Ashfall Fossil Beds State Historical Park C

42.20

-98.20

12.70

Middle

Barstovian

-7.00*

21

Fox and Koch 2003

146 APPENDIX D1: STABLE ISOTOPES PE Pit

36.10

-100.00

9.60

Middle

Clarendonian

-7.37*

19

Fox and Koch 2003

Minimum Quarry

39.40

-100.10

9.55

Middle

Clarendonian

-6.98*

21

Thomasson 1991; Fox and Koch 2003

Greenwood Canyon

41.50

-103.10

9.10

Middle

Clarendonian

-6.80*

22

Fox and Koch 2003

Box T

36.20

-100.10

8.75

Middle

Clarendonian

-7.50*

18

Fox and Koch 2003

Higgins locality

36.10

-100.00

8.75

Middle

Clarendonian

-7.10*

20

Fox and Koch 2003

Wildohorse Canyon

41.30

-102.40

8.65

Middle

Clarendonian

-6.28*

28

Fox and Koch 2003

Cole Highway Pit

36.04

-100.01

9.50

Middle

Clarendonian

-9.60†

13

Fox and Fisher 2004

Rock Ledge Mastodon Quarry

42.73

-99.88

10.00

Middle

Clarendonian

-8.80†

18

Fox and Fisher 2004

Megabelodon Quarry

42.43

-100.50

11.00

Middle

Clarendonian

-10.40†

4

Fox and Fisher 2004

Myers Farm

40.10

-98.47

12.00

Middle

Barstovian

-13.00†

0

Damuth et al. 2002; Fox and Fisher 2004

George Elliott Place

42.71

-99.79

12.00

Middle

Barstovian

-9.50†

13

Fox and Fisher 2004

Hottell Ranch

41.32

-103.56

14.00

Middle

Barstovian

-8.80†

15

Fox and Fisher 2004

Burge Quarry A

42.74

-100.42

11.00

Middle

Clarendonian

-9.50†

13

Wang et al. 1994; Fox and Fisher 2004

Ewert Quarry

42.83

-101.17

11.00

Middle

Clarendonian

-9.20†

15

Fox and Fisher 2004

Devil's Gulch Quarry

42.71

-99.79

13.70

Middle

Barstovian

-8.60†

19

Fox and Fisher 2004

North Shore

41.16

-101.48

9.00

Middle

Clarendonian

-9.05†

16

Passey et al. 2002

Pratt Slide

42.37

-100.03

9.00

Middle

Clarendonian

-10.92†

4

Passey et al. 2002

Xmas Quarry

42.53

-100.14

9.00

Middle

Clarendonian

-10.90†

4


Zochol Quarry

42.00

-103.00

10.00

Middle

Clarendonian

-9.15†

16

Passey et al. 2002

Annie's Geese Cross

42.49

-97.38

12.00

Middle

Barstovian

-9.60†

13

Passey et al. 2002

Hazard Homestead

40.03

-100.53

12.00

Middle

Barstovian

-8.10†

23

Passey et al. 2002

A&C Risley Farm

35.04

-100.52

10.50

Middle

Clarendonian

-11.00†

3

Passey et al. 2002

Couch Ranch

36.00

-101.00

10.50

Middle

Clarendonian

-9.70†

12

Passey et al. 2002

147 APPENDIX D1: STABLE ISOTOPES Stanton Ranch

35.02

-100.49

10.50

Middle

Clarendonian

-11.30†

1

Passey et al. 2002

MacAdams Quarry

35.04

-100.54

11.00

Middle

Clarendonian

-10.68†

5

Passey et al. 2002

Clayton Quarry

42.69

-99.92

10.00

Middle

Clarendonian

-9.45†

14

Clouthier 1994

Burge Quarry B

42.74

-100.42

12.00

Middle

Barstovian

-11.50†

0

Clouthier 1994

Kimball

41.20

-103.70

7.25

Late

Hemphillian

-5.57*

32

Fox and Koch 2003

Breakneck Hill

41.60

-102.80

7.25

Late

Hemphillian

-7.20*

20

Fox and Koch 2003

Lake McConnaughy Dam

41.20

-101.70

7.25

Late

Hemphillian

-7.02*

21

Fox and Koch 2003

Lake McConnaughy Dam

41.20

-101.70

7.25

Late

Hemphillian

-9.50†

10

Passey et al. 2002

RR at FM 211

33.30

-101.50

6.80

Late

Hemphillian

-6.50*

25

Fox and Koch 2003

Yellowhouse Canyon A2

33.50

-101.60

6.80

Late

Hemphillian

-5.23*

34

Fox and Koch 2003

Yellowhouse Canyon B2

33.50

-101.60

6.80

Late

Hemphillian

-6.98*

21

Fox and Koch 2003

Coffee Ranch, TX

35.44

-100.31

6.65

Late

Hemphillian

-6.92*

21

Fox and Koch 2003

Coffee Ranch, TX

35.44

-100.31

6.65

Late

Hemphillian

-6.90†

27


Bellview

34.90

-103.10

6.40

Late

Hemphillian

-7.20*

20

Fox and Koch 2003

Alien Canyon A

37.00

-100.60

4.20

Late

Blancan

-4.70*

38

Fox and Koch 2003

Alien Canyon B

37.00

-100.60

3.99

Late

Blancan

-4.80*

38

Fox and Koch 2003

Jack Swayze Quarry

37.22

-99.47

8.00

Late

Hemphillian

-9.76†

8

Fox and Fisher 2004

V.V. Parker Pits

36.19

-100.33

8.00

Late

Hemphillian

-9.60†

9

Fox and Fisher 2004

Port of Entry Pit

36.11

-99.78

8.00

Late

Hemphillian

-10.46†

4

Fox and Fisher 2004

Big Springs

43.00

-98.00

2.30

Late

Blancan

-3.64†

59


Big Springs

42.00

-98.00

2.30

Late

Blancan

-2.10†

69

Passey et al. 2002

Quinn Gravel Pit

43.00

-101.00

2.50

Late

Blancan

-3.87†

58

Passey et al. 2002

South Wind Prospect

42.00

-98.00

2.50

Late

Blancan

-8.25†

27

Passey et al. 2002

148 APPENDIX D1: STABLE ISOTOPES Hall Gravel Pit

42.43

-99.93

3.00

Late

Blancan

-3.10†

63

Passey et al. 2002

Broadwater

41.60

-102.74

3.00

Late

Blancan

-4.93†

50


Lisco

41.51

-102.58

4.00

Late

Blancan

-6.30†

41

Passey et al. 2002

Devil's Nest Airstrip

42.49

-97.43

5.00

Late

Hemphillian

-4.20†

55

Passey 2002, Damuth 2002

Ashton Quarry

41.21

-98.45

6.00

Late

Hemphillian

-8.40†

21

Passey et al. 2002

Ashton Local Fauna

42.00

-99.00

6.00

Late

Hemphillian

-9.30†

15

Passey et al. 2002

Mailbox Prospect

42.23

-98.07

6.00

Late

Hemphillian

-9.20†

15


Rick Irwin

42.43

-99.34

6.00

Late

Hemphillian

-6.46†

34

Passey et al. 2002

Uptegrove local fauna

41.15

-102.54

6.00

Late

Hemphillian

-9.75†

12

Passey et al. 2002

ZX-Bar

42.19

-103.77

6.00

Late

Hemphillian

-8.93†

17

Passey et al. 2002

Cambridge local fauna

40.52

-100.38

7.00

Late

Hemphillian

-9.20†

12


Greenwood Canyon

41.27

-103.03

7.00

Late

Hemphillian

-8.02†

20

Passey et al. 2002

Oshkosh local fauna

41.20

-102.23

7.00

Late

Hemphillian

-9.27†

12

Passey et al. 2002

Aphelops Draw Q#1

42.20

-103.79

8.00

Late

Hemphillian

-9.50†

10


Lemoyne Quarry

41.46

-101.88

8.00

Late

Hemphillian

-8.50†

17

Passey et al. 2002

The Pits

42.11

-103.46

8.00

Late

Hemphillian

-9.70†

9

Passey et al. 2002

Mt. Blanco

34.00

-101.00

2.00

Late

Blancan

-6.00†

43

Passey et al. 2002

Mt. Blanco

34.00

-101.00

2.00

Late

Blancan

-1.00†

77

Passey et al. 2002

Red Light/Love Ranch

31.00

-105.00

2.00

Late

Blancan

-0.20†

82

Passey et al. 2002

Bridwell Ranch

34.00

-101.00

3.00

Late

Blancan

0.10†

84

Passey et al. 2002

Bridwell Ranch

34.00

-101.00

3.00

Late

Blancan

-3.90†

57

Passey et al. 2002

Bailey Farm

35.00

-101.00

6.00

Late

Hemphillian

-5.90†

37

Passey et al. 2002

Cleo Hibbard Ranch

35.00

-101.00

6.00

Late

Hemphillian

-6.10†

36

Passey et al. 2002

149 APPENDIX D1: STABLE ISOTOPES Janes-Prentice Gravel Pit

33.00

-102.00

7.00

Late

Hemphillian

-9.30†

11

Passey et al. 2002

Box T Quarry

36.14

-100.05

8.00

Late

Hemphillian

-9.50†

10

Passey et al. 2002

Safford-Duncan Magill Ranch Box T Quarry

32.00 42.00 36.14

-109.00 -100.00 -100.05

3.00 4.00 6.50

Late Late Late

Blancan Blancan Hemphillian

-9.20† -10.95† -8.80†

20 7 15

Clouthier 1994 Clouthier 1994 Clouthier 1994

150

APPENDIX D2: MEAN ANNUAL PRECIPITATION Location Name

Latitude

Longitude

Age 14.65

Time Slice Early

South Bijou Hill

43.49

-99.27

South Bijou Hill

43.49

-99.27

14.66

South Bijou Hill

43.49

-99.27

South Bijou Hill

43.49

South Bijou Hill

NALMA Barstovian

MAP (mm) 332.82

Reference Retallack, pers comm.

Early

Barstovian

399.09

Retallack, pers comm.

14.68

Early

Barstovian

286.61


-99.27

14.69

Early

Barstovian

292.52


43.49

-99.27

14.70

Early

Barstovian

372.08


South Bijou Hill

43.49

-99.27

14.99

Early

Barstovian

345.22


South Bijou Hill

43.49

-99.27

15.00

Early

Barstovian

251.36


South Bijou Hill

43.49

-99.27

15.08

Early

Barstovian

427.34


South Bijou Hill

43.49

-99.27

15.09

Early

Barstovian

367.96


Mitchell

42.20

-103.79

16.10

Early

Hemingfordian

349.78


Mitchell

42.20

-103.79

16.11

Early

Hemingfordian

325.81


Mitchell

42.20

-103.79

16.15

Early

Hemingfordian

402.16


Mitchell

42.20

-103.79

16.16

Early

Hemingfordian

385.03


Martin

43.14

-101.88

16.70

Early

Hemingfordian

697.46


Mitchell

42.19

-103.77

16.71

Early

Hemingfordian

659.37


Chadron

42.55

-102.86

17.67

Early

Hemingfordian

519.13


Chadron

42.55

-102.86

17.67

Early

Hemingfordian

456.88


Chadron

42.58

-103.04

17.81

Early

Hemingfordian

543.97


Chadron

42.58

-103.04

17.92

Early

Hemingfordian

343.78


Marsland

42.37

-103.30

17.93

Early

Hemingfordian

462.52


Marsland

42.37

-103.30

17.97

Early

Hemingfordian

544.17


Marsland

42.37

-103.30

18.02

Early

Hemingfordian

424.49


Marsland

42.37

-103.30

18.06

Early

Hemingfordian

529.56


151 APPENDIX D2: MEAN ANNUAL PRECIPITATION Marsland

42.37

-103.30

18.10

Early

Hemingfordian

413.40


Chadron

42.58

-103.06

18.31

Early

Hemingfordian

350.02


Chadron

42.58

-103.06

18.35

Early

Hemingfordian

326.03


Hemingford

42.42

-103.06

18.39

Early

Hemingfordian

338.12


Chadron

42.58

-103.06

18.39

Early

Hemingfordian

319.97


Hemingford

42.42

-103.06

18.42

Early

Hemingfordian

396.71


Chadron

42.58

-103.06

18.43

Early

Hemingfordian

350.10


Chadron

42.55

-102.86

18.44

Early

Hemingfordian

307.75


Hemingford

42.42

-103.06

18.46

Early

Hemingfordian

326.09


Chadron

42.55

-102.86

18.51

Early

Hemingfordian

554.52


Agate

42.42

-103.73

18.61

Early

Hemingfordian

375.40


Agate

42.42

-103.73

18.63

Early

Hemingfordian

381.27


Agate

42.42

-103.73

18.65

Early

Hemingfordian

387.11


Agate

42.42

-103.73

18.66

Early

Hemingfordian

410.11


Agate

42.42

-103.73

18.70

Early

Hemingfordian

398.73


Hemingford

42.37

-103.02

18.71

Early

Hemingfordian

396.97


Agate

42.42

-103.73

18.72

Early

Hemingfordian

351.81


Agate

42.42

-103.73

18.73

Early

Hemingfordian

410.21


Hemingford

42.37

-103.02

18.77

Early

Hemingfordian

458.04


Agate

42.42

-103.73

18.77

Early

Hemingfordian

351.87


Agate

42.42

-103.73

18.79

Early

Hemingfordian

321.55


Agate

42.42

-103.73

18.81

Early

Hemingfordian

375.64


Agate

42.42

-103.73

18.84

Early

Hemingfordian

438.42


Agate

42.42

-103.73

18.87

Early

Hemingfordian

339.94


Eagle Crags

42.72

-103.88

18.87

Early

Hemingfordian

345.98


152 APPENDIX D2: MEAN ANNUAL PRECIPITATION Agate

42.42

-103.73

18.88

Early

Hemingfordian

345.99


Agate

42.42

-103.73

18.90

Early

Hemingfordian

421.76


Eagle Crags

42.72

-103.88

18.90

Early

Hemingfordian

352.02


Eagle Crags

42.72

-103.88

18.95

Early

Hemingfordian

460.48


Agate

42.42

-103.73

19.00

Early

Hemingfordian

364.06


Mission

43.32

-100.85

19.00

Early

Hemingfordian

483.84


Eagle Crags

42.72

-103.88

19.01

Early

Hemingfordian

334.00


Mission

43.32

-100.85

19.02

Early

Hemingfordian

328.81


Agate

42.42

-103.73

19.03

Early

Hemingfordian

404.91


Eagle Crags

42.72

-103.88

19.03

Early

Hemingfordian

352.16


Eagle Crags

42.72

-103.88

19.06

Early

Hemingfordian

421.98


Agate

42.42

-103.73

19.06

Early

Hemingfordian

327.95


Mission

43.32

-100.85

19.07

Early

Hemingfordian

316.91


Agate

42.42

-103.73

19.08

Early

Hemingfordian

375.97


Eagle Crags

42.72

-103.88

19.09

Early

Hemingfordian

315.67


Eagle Crags

42.72

-103.88

19.11

Early

Hemingfordian

346.23


Mission

43.32

-100.85

19.11

Early

Hemingfordian

457.97


Eagle Crags

42.72

-103.88

19.13

Early

Hemingfordian

405.04


Mission

43.32

-100.85

19.15

Early

Hemingfordian

340.77


Eagle Crags

42.72

-103.88

19.16

Early

Hemingfordian

340.24


Mission

43.32

-100.85

19.17

Early

Hemingfordian

334.88


Mission

43.32

-100.85

19.18

Early

Hemingfordian

452.79


Eagle Crags

42.72

-103.88

19.20

Early

Hemingfordian

352.35


Eagle Crags

42.72

-103.88

19.22

Early

Hemingfordian

416.56


Eagle Crags

42.72

-103.88

19.26

Early

Hemingfordian

358.41


153 APPENDIX D2: MEAN ANNUAL PRECIPITATION Eagle Crags

42.72

-103.88

19.28

Early

Hemingfordian

346.42


Eagle Crags

42.72

-103.88

19.30

Early

Hemingfordian

427.95


Agate

42.42

-103.73

19.33

Early

Hemingfordian

376.37


Eagle Crags

42.72

-103.88

19.35

Early

Hemingfordian

328.24


Eagle Crags

42.72

-103.88

19.37

Early

Hemingfordian

322.11


Eagle Crags

42.72

-103.88

19.39

Early

Hemingfordian

416.80


Eagle Crags

42.72

-103.88

19.45

Early

Hemingfordian

352.63


Agate

42.42

-103.73

19.46

Early

Hemingfordian

358.60


Eagle Crags

42.72

-103.88

19.47

Early

Hemingfordian

358.64


Agate

42.42

-103.73

19.48

Early

Hemingfordian

439.30


Eagle Crags

42.72

-103.88

19.49

Early

Hemingfordian

428.23


Eagle Crags

42.72

-103.88

19.54

Early

Hemingfordian

417.00


Eagle Crags

42.72

-103.88

19.57

Early

Hemingfordian

411.36


Eagle Crags

42.72

-103.88

19.59

Early

Hemingfordian

340.69


Eagle Crags

42.72

-103.88

19.61

Early

Hemingfordian

316.16


Eagle Crags

42.72

-103.88

19.65

Early

Hemingfordian

346.82


Eagle Crags

42.72

-103.88

19.68

Early

Hemingfordian

417.20


Eagle Crags

42.72

-103.88

19.71

Early

Hemingfordian

370.83


Eagle Crags

42.72

-103.88

19.73

Early

Hemingfordian

434.17


Eagle Crags

42.72

-103.88

19.79

Early

Hemingfordian

388.56


Eagle Crags

42.72

103.88

19.82

Early

Hemingfordian

405.97


Eagle Crags

42.72

-103.88

19.84

Early

Hemingfordian

439.90


Eagle Crags

42.72

-103.88

19.87

Early

Hemingfordian

428.77


Eagle Crags

42.72

-103.88

19.90

Early

Hemingfordian

406.09


Eagle Crags

42.72

-103.88

19.94

Early

Hemingfordian

423.23


154 APPENDIX D2: MEAN ANNUAL PRECIPITATION Eagle Crags

42.72

-103.88

19.98

Early

Hemingfordian

417.62


Eagle Crags

42.72

-103.88

20.01

Early

Hemingfordian

406.23


Eagle Crags

42.72

-103.88

20.04

Early

Hemingfordian

423.38


Eagle Crags

42.72

-103.88

20.12

Early

Hemingfordian

383.13


Eagle Crags

42.72

-103.88

20.22

Early

Hemingfordian

467.90


Norden bridge

42.79

-100.03

21.79

Early

Arikareean

409.49


Norden bridge

42.79

-100.03

21.82

Early

Arikareean

420.33


Norden bridge

42.79

-100.03

21.88

Early

Arikareean

441.64


Mission

43.32

-100.87

21.96

Early

Arikareean

462.10


Mission

43.32

-100.87

21.98

Early

Arikareean

337.55


Mission

43.32

-100.87

22.00

Early

Arikareean

355.41


Mission

43.32

-100.87

22.03

Early

Arikareean

451.47


Agate

42.42

-103.73

22.03

Early

Arikareean

434.51


Mission

43.32

-100.87

22.06

Early

Arikareean

367.21


Mission

43.32

-100.87

22.07

Early

Arikareean

373.06


Norden bridge

42.42

-103.73

22.10

Early

Arikareean

441.77


Mission

43.32

-100.87

22.10

Early

Arikareean

456.95


Agate

42.42

-103.73

22.18

Early

Arikareean

382.97


Mission

43.32

-100.87

22.19

Early

Arikareean

378.99


Mission

43.32

-100.87

22.22

Early

Arikareean

367.38


Mission

43.32

-100.87

22.25

Early

Arikareean

478.40


Agate

42.42

-103.73

22.27

Early

Arikareean

388.85


Mission

43.32

-100.87

22.28

Early

Arikareean

373.28


Mission

43.32

-100.87

22.30

Early

Arikareean

343.83


Mission

43.32

-100.87

22.32

Early

Arikareean

396.37


155 APPENDIX D2: MEAN ANNUAL PRECIPITATION Agate

42.42

-103.73

22.44

Early

Arikareean

462.21


Agate

42.42

-103.73

22.55

Early

Arikareean

383.07


Agate

42.42

-103.73

22.70

Early

Arikareean

434.71


Agate

42.42

-103.73

22.87

Early

Arikareean

377.26


Smiley Canyon

42.66

-103.55

23.00

Early

Arikareean

407.53


Echo Quarry

42.10

-103.44

15.00

Early

Barstovian

2731.62

Wang et al. 1994; Damuth et al. 2002; Passey et al. 2002

West Surface Quarry

42.09

-103.43

15.00

Early

Barstovian

Thompson Quarry

42.19

-103.75

17.50

Early

Hemingfordian

2138.93


Eubanks Fauna (CP75B):

40.52

-103.55

15.00

Early

Barstovian

1107.90

Damuth et al. 2002

Observation Quarry (CP111):

42.42

-102.50

15.00

Early

Barstovian

1059.21

Damuth et al. 2002

Foley Quarry (CP107):

42.24

-103.02

17.00

Early

Hemingfordian

1287.02

Damuth et al. 2002

Ginn Quarry (CP109A):

42.39

-102.47

17.00

Early

Hemingfordian

600.42

Damuth et al. 2002

Aletomeryx Quarry (CP105):

42.45

-102.01

18.00

Early

Hemingfordian

2536.87

Damuth et al. 2002

University of Kansas Quarry A (CP71):

40.54

-103.16

18.00

Early

Hemingfordian

841.60

Damuth et al. 2002

Flint Hill Local Fauna (CP88):

43.08

-101.52

18.00

Early

Hemingfordian

938.73

Damuth et al. 2002

Humbug Quarry (CP110):

42.10

-103.44

15.00

Early

Barstovian

2560.14

Damuth et al. 2002


Marsland

42.69

-103.41

18.50

Early

Hemingfordian

900.00

Axelrod 1985


42.80

-100.00

14.30

Middle

Barstovian

190.08

Damuth et al. 2002; Fox and Koch 2003

Myers Farm

40.10

-98.47

12.00

Middle

Barstovian

1888.09

Damuth et al. 2002; Fox and Fisher 2004

Merritt Dam

42.65

-100.86

9.19

Middle

Clarendonian

370.97


Merritt Dam

42.65

-100.86

9.36

Middle

Clarendonian

301.65


Merritt Dam

42.65

-100.86

9.40

Middle

Clarendonian

348.40


Merritt Dam

42.65

-100.86

9.98

Middle

Clarendonian

348.72


Mitchell

42.17

-103.73

10.00

Middle

Clarendonian

422.26


Merritt Dam

42.65

-100.86

10.02

Middle

Clarendonian

277.87


156 APPENDIX D2: MEAN ANNUAL PRECIPITATION Olcott Hill

42.17

-103.73

10.11

Middle

Clarendonian

352.80


Olcott Hill

42.17

-103.73

10.26

Middle

Clarendonian

411.94


Valentine

42.91

-100.48

10.32

Middle

Clarendonian

404.96


Valentine

42.91

-100.48

10.35

Middle

Clarendonian

360.43


Valentine

42.91

-100.48

10.36

Middle

Clarendonian

542.45


Morland

39.37

-100.08

10.42

Middle

Clarendonian

386.64


Olcott Hill

42.17

-103.73

10.45

Middle

Clarendonian

363.88


Olcott Hill

42.17

-103.73

10.58

Middle

Clarendonian

385.57


Big Spring Canyon

43.11

-101.94

10.60

Middle

Clarendonian

266.17

Damuth et al. 2002; Retallack, pers comm.

Olcott Hill

42.17

-103.73

10.73

Middle

Clarendonian

330.70


Morland

39.37

-100.08

11.10

Middle

Clarendonian

418.58


Valentine

42.91

-100.48

11.41

Middle

Clarendonian

339.97


Valentine

42.91

-100.48

11.43

Middle

Clarendonian

322.27


Valentine

42.91

-100.48

11.45

Middle

Clarendonian

363.31


Valentine

42.91

-100.48

11.46

Middle

Clarendonian

340.10


Valentine

42.91

-100.48

11.49

Middle

Clarendonian

334.28


Olcott Hill

42.17

-103.73

11.62

Middle

Barstovian

473.37


Norden quarry

42.79

-100.03

11.67

Middle

Barstovian

403.53


Norden quarry

42.79

-100.03

11.68

Middle

Barstovian

376.03


Norden quarry

42.79

-100.03

11.69

Middle

Barstovian

516.62


Olcott Hill

42.17

-103.73

11.71

Middle

Barstovian

347.71


Broadwater

41.55

-102.72

12.96

Middle

Barstovian

550.84


Broadwater

41.55

-102.72

13.07

Middle

Barstovian

387.94


South Bijou Hill

43.49

-99.27

14.05

Middle

Barstovian

369.74


South Bijou Hill

43.49

-99.27

14.06

Middle

Barstovian

380.61


157 APPENDIX D2: MEAN ANNUAL PRECIPITATION South Bijou Hill

43.49

-99.27

14.07

Middle

Barstovian

353.33


South Bijou Hill

43.49

-99.27

14.08

Middle

Barstovian

438.45


South Bijou Hill

43.49

-99.27

14.09

Middle

Barstovian

353.40


South Bijou Hill

43.49

-99.27

14.10

Middle

Barstovian

347.89


South Bijou Hill

43.49

-99.27

14.10

Middle

Barstovian

412.69


South Bijou Hill

43.49

-99.27

14.12

Middle

Barstovian

308.43


South Bijou Hill

43.49

-99.27

14.12

Middle

Barstovian

342.42


South Bijou Hill

43.49

-99.27

14.13

Middle

Barstovian

423.25


South Bijou Hill

43.49

-99.27

14.14

Middle

Barstovian

342.45


South Bijou Hill

43.49

-99.27

14.14

Middle

Barstovian

308.50


South Bijou Hill

43.49

-99.27

14.15

Middle

Barstovian

325.63


South Bijou Hill

43.49

-99.27

14.16

Middle

Barstovian

407.66


South Bijou Hill

43.49

-99.27

14.16

Middle

Barstovian

331.32


South Bijou Hill

43.49

-99.27

14.17

Middle

Barstovian

302.82


South Bijou Hill

43.49

-99.27

14.18

Middle

Barstovian

308.61


Snake Creek Fauna (CP115B):

42.11

-103.46

9.00

Middle

Clarendonian

604.90

Damuth et al. 2002

Blue Jay Quarry (CP116B):

42.42

-98.15

9.00

Middle

Clarendonian

1590.65

Damuth et al. 2002

Wakeeney Creek Fauna (CP123A):

39.05

-99.45

10.00

Middle

Clarendonian

266.54

Damuth et al. 2002

Little Beaver B Quarry (CP116A):

42.90

-100.47

10.00

Middle

Clarendonian

1402.74

Damuth et al. 2002

Trail Creek Quarry Local Fauna (CP56):

41.25

-104.43

12.00

Middle

Barstovian

325.86

Damuth et al. 2002

Kennesaw Fauna, (CP76):

40.59

-103.29

12.00

Middle

Barstovian

1143.92

Damuth et al. 2002

Carrot Top Quarry (CP114A)

42.47

-100.04

13.50

Middle

Barstovian

1735.33

Damuth et al. 2002

Horse and Mastodon Quarry (CP75C):

40.49

-104.04

13.50

Middle

Barstovian

633.87

Damuth et al. 2002

Kilgore

42.80

-101.01

1314

Middle

Barstovian

825.00

MacGinitie 1962; Axelrod 1985

Beaver Co.

36.75

-100.48

11.00

Middle

Clarendonian

825.00

Axelrod 1985

158 APPENDIX D2: MEAN ANNUAL PRECIPITATION Clarendon

34.93

-100.88

11.00

Middle

Clarendonian

760.00

Axelrod 1985

Garden Co.

41.40

-102.35

NA

Middle

Clarendonian

500.00

Thomasson 1980

Borchers Badlands north

37.18

-100.37

2.00

Late

Blancan

438.84


Borchers Badlands south

37.16

-100.37

2.12

Late

Blancan

562.96



37.16

-100.37

2.23

Late

Blancan

597.68



37.16

-100.37

2.23

Late

Blancan

474.19


Ainsworth

42.82

-100.56

2.25

Late

Blancan

393.11


Ainsworth

42.63

-99.84

2.26

Late

Blancan

365.95


Long Pine

42.65

-99.84

2.26

Late

Blancan

332.42


Ainsworth

42.65

-99.84

2.27

Late

Blancan

440.49



37.16

-100.37

2.37

Late

Blancan

558.69


Ainsworth

42.68

-99.98

2.44

Late

Blancan

315.70



37.16

-100.37

2.45

Late

Blancan

449.31


Ainsworth

42.68

-99.98

2.47

Late

Blancan

441.22



37.16

-100.37

2.50

Late

Blancan

549.79



37.16

-100.37

2.54

Late

Blancan

386.67


Broadwater

41.60

-102.76

2.61

Late

Blancan

309.71



37.16

-100.37

2.62

Late

Blancan

397.42



37.16

-100.37

2.64

Late

Blancan

554.40



37.18

-100.37

2.65

Late

Blancan

554.57



37.16

-100.37

2.73

Late

Blancan

508.24



37.16

-100.37

2.81

Late

Blancan

503.53



37.18

-100.37

2.84

Late

Blancan

554.72



37.18

-100.37

3.04

Late

Blancan

503.86



37.18

-100.37

3.27

Late

Blancan

607.09



37.18

-100.37

3.38

Late

Blancan

429.36


159 APPENDIX D2: MEAN ANNUAL PRECIPITATION Borchers Badlands north

37.18

-100.37

3.45

Late

Blancan

550.68



37.18

-100.37

3.56

Late

Blancan

537.08


Crooked Creek north

37.18

-100.39

3.67

Late

Blancan

397.97


Broadwater

41.60

-102.76

3.76

Late

Blancan

333.11


Crooked Creek north

37.18

-100.39

3.82

Late

Blancan

460.24


Meade

37.22

-100.48

3.82

Late

Blancan

521.22


Meade

37.22

-100.48

3.91

Late

Blancan

448.29


Crooked Creek north

37.18

-100.39

3.93

Late

Blancan

354.52


Meade

37.22

-100.48

4.00

Late

Blancan

463.27


Crooked Creek north

37.18

-100.39

4.05

Late

Blancan

387.43


Broadwater

41.60

-102.76

4.09

Late

Blancan

472.14


Crooked Creek north

37.18

-100.39

4.10

Late

Blancan

518.85


Meade

37.22

-100.48

4.10

Late

Blancan

330.75


Meade

37.22

-100.48

4.17

Late

Blancan

374.87


Meade

37.22

-100.48

4.23

Late

Blancan

570.62


Crooked Creek north

37.18

-100.39

4.27

Late

Blancan

365.74


Broadwater

41.60

-102.76

4.43

Late

Blancan

361.51


Broadwater

41.60

-102.76

4.43

Late

Blancan

275.12


Broadwater

41.60

-102.76

4.59

Late

Blancan

339.13


Broadwater

41.60

-102.76

4.69

Late

Blancan

426.46


Scott Lake

38.63

-100.81

4.97

Late

Blancan

380.51


Scott Lake

38.63

-100.81

5.07

Late

Blancan

325.31


Scott Lake

38.63

-100.81

5.12

Late

Blancan

385.95


Scott Lake

38.63

-100.81

5.23

Late

Blancan

417.73


Broadwater

41.60

-102.74

5.25

Late

Blancan

421.53


160 APPENDIX D2: MEAN ANNUAL PRECIPITATION Broadwater

41.60

-102.76

5.27

Late

Blancan

516.88


Broadwater

41.60

-102.74

5.32

Late

Blancan

442.45


Scott Lake

38.63

-100.81

5.35

Late

Hemphillian

396.72


Lisco

41.52

-102.65

5.42

Late

Hemphillian

316.72


Harrisburg

41.50

-103.72

5.45

Late

Hemphillian

421.85


Kimball

41.20

-103.65

5.45

Late

Hemphillian

287.43


Scott Lake

38.63

-100.81

5.46

Late

Hemphillian

386.07


Broadwater

41.60

-102.76

5.56

Late

Hemphillian

275.46


Scott Lake

38.63

-100.81

5.58

Late

Hemphillian

358.94


Broadwater

41.60

-102.76

5.59

Late

Hemphillian

400.41


Scott Lake

38.63

-100.81

5.66

Late

Hemphillian

273.49


Scott Lake

38.63

-100.81

5.71

Late

Hemphillian

285.24


Almena

39.88

-99.69

5.71

Late

Hemphillian

398.89


Almena

39.88

-99.71

5.72

Late

Hemphillian

321.30


Crooked Creek south

37.16

-100.39

5.73

Late

Hemphillian

280.56


Broadwater

41.60

-102.74

5.75

Late

Hemphillian

281.48


Almena

39.88

-99.71

5.75

Late

Hemphillian

315.59


Crooked Creek south

37.16

-100.39

5.75

Late

Hemphillian

292.35


Clayton

39.76

-100.09

5.76

Late

Hemphillian

360.79


Almena

39.88

-99.69

5.77

Late

Hemphillian

355.25


Harrisburg

41.50

-103.72

5.78

Late

Hemphillian

316.82


Kimball

41.21

-103.65

5.78

Late

Hemphillian

339.77


Clayton

39.76

-100.09

5.78

Late

Hemphillian

274.67


Crooked Creek south

37.16

-100.39

5.79

Late

Hemphillian

344.07


Almena

39.88

-99.71

5.80

Late

Hemphillian

355.28


161 APPENDIX D2: MEAN ANNUAL PRECIPITATION Clayton

39.76

-100.09

5.81

Late

Hemphillian

292.39


Crooked Creek south

37.16

-100.39

5.81

Late

Hemphillian

430.67


Clayton

39.76

-100.09

5.84

Late

Hemphillian

360.87


Crooked Creek south

37.16

-100.39

5.84

Late

Hemphillian

388.26


Scott Lake

38.63

-100.81

5.84

Late

Hemphillian

347.96


Almena

39.88

-99.71

5.84

Late

Hemphillian

409.70


Crooked Creek south

37.16

-100.39

5.87

Late

Hemphillian

349.76


Clayton

39.76

-100.09

5.88

Late

Hemphillian

404.42


Crooked Creek south

37.16

-100.39

5.90

Late

Hemphillian

274.74


Clayton

39.76

-100.09

5.93

Late

Hemphillian

409.80


Scott Lake

38.63

-100.81

5.94

Late

Hemphillian

319.88


Crooked Creek south

37.16

-100.39

5.94

Late

Hemphillian

315.74


Clayton

39.76

-100.09

5.97

Late

Hemphillian

446.35


Crooked Creek south

37.16

-100.39

5.99

Late

Hemphillian

321.52


Hays

39.15

-99.28

6.00

Late

Hemphillian

249.58


Crooked Creek south

37.16

-100.39

6.04

Late

Hemphillian

327.29


Scott Lake

38.63

-100.81

6.04

Late

Hemphillian

535.78


Clayton

39.76

-100.09

6.09

Late

Hemphillian

393.94


Clayton

39.76

-100.09

6.10

Late

Hemphillian

539.07


Lisco

41.52

-102.65

6.17

Late

Hemphillian

311.22


Ogalalla

41.20

-101.66

6.21

Late

Hemphillian

351.19


Scott Lake

38.63

-100.81

6.27

Late

Hemphillian

302.79


Clayton

39.76

-100.09

6.30

Late

Hemphillian

539.38


Ellis

39.06

-99.57

6.34

Late

Hemphillian

353.26


Ellis

39.04

-99.53

6.34

Late

Hemphillian

438.32


162 APPENDIX D2: MEAN ANNUAL PRECIPITATION Scott Lake

38.63

-100.81

6.40

Late

Hemphillian

331.34


Broadwater

41.60

-102.74

6.41

Late

Hemphillian

293.55


Clayton

39.76

-100.09

6.46

Late

Hemphillian

492.06


Clayton

39.76

-100.09

6.50

Late

Hemphillian

553.44


Scott Lake

38.63

-100.81

6.50

Late

Hemphillian

273.67


Ellis

39.05

-99.57

6.51

Late

Hemphillian

325.34


Clayton

39.76

-100.09

6.54

Late

Hemphillian

521.05


Harrisburg

41.50

-103.72

6.56

Late

Hemphillian

275.81


Broadwater

41.60

-102.74

6.57

Late

Hemphillian

334.28


Scott Lake

38.63

-100.81

6.58

Late

Hemphillian

314.36


Scott Lake

38.63

-100.81

6.65

Late

Hemphillian

337.05


Ellis

39.06

-99.57

6.68

Late

Hemphillian

347.78


Ellis

39.04

-99.53

6.68

Late

Hemphillian

417.75


Hays, KS

39.15

-99.28

6.68

Late

Hemphillian

358.83


Clayton

39.76

-100.09

6.74

Late

Hemphillian

316.36


Scott Lake

38.63

-100.81

6.76

Late

Hemphillian

320.12


Ogalalla

41.20

-101.66

6.76

Late

Hemphillian

269.87


Clayton

39.76

-100.09

6.77

Late

Hemphillian

327.89


Clayton

39.76

-100.09

6.83

Late

Hemphillian

540.20


Scott Lake

38.63

-100.81

6.83

Late

Hemphillian

402.61


Scott Lake

38.63

-100.81

6.91

Late

Hemphillian

397.33


Ellis

39.01

-99.57

7.02

Late

Hemphillian

308.32


Ellis

39.13

-99.55

7.02

Late

Hemphillian

285.17


Hays

39.01

-99.34

7.02

Late

Hemphillian

279.31


Lisco

41.52

-102.65

7.03

Late

Hemphillian

288.00


163 APPENDIX D2: MEAN ANNUAL PRECIPITATION Scott Lake

38.63

-100.81

7.06

Late

Hemphillian

342.78


Hays

38.88

-99.46

7.07

Late

Hemphillian

237.57


Hays

38.88

-99.46

7.12

Late

Hemphillian

267.48


Ogalalla

41.20

-101.66

7.13

Late

Hemphillian

276.00


Scott Lake

38.63

-100.81

7.14

Late

Hemphillian

308.78


Scott Lake

38.63

-100.81

7.22

Late

Hemphillian

413.32


Harrisburg

41.50

-103.72

7.22

Late

Hemphillian

373.98


Scott Lake

38.63

-100.81

7.32

Late

Hemphillian

397.48


Ellis

39.04

-99.53

7.36

Late

Hemphillian

364.42


Scott Lake

38.63

-100.81

7.42

Late

Hemphillian

392.18


Scott Lake

38.63

-100.81

7.50

Late

Hemphillian

386.84


Ash Hollow

41.29

-102.12

7.52

Late

Hemphillian

270.27


Ellis

39.01

-99.57

7.53

Late

Hemphillian

255.69


Ogalalla

41.20

-101.66

7.59

Late

Hemphillian

282.16


Ellis

39.04

-99.55

7.60

Late

Hemphillian

567.07


Scott Lake

38.63

-100.81

7.65

Late

Hemphillian

291.53


Ellis

39.04

-99.53

7.70

Late

Hemphillian

507.60


Ellis

39.04

-99.53

7.70

Late

Hemphillian

353.47


Ellis

39.04

-99.53

7.70

Late

Hemphillian

453.81


Ellis

39.13

-99.55

7.70

Late

Hemphillian

386.17


Ellis

39.01

-99.57

7.70

Late

Hemphillian

261.66


Ash Hollow

41.29

-102.12

7.92

Late

Hemphillian

418.68


Ellis

39.04

-99.55

8.04

Late

Hemphillian

359.04


Ash Hollow

41.29

-102.12

8.06

Late

Hemphillian

341.44


Lisco

41.52

-102.65

8.11

Late

Hemphillian

363.54


164 APPENDIX D2: MEAN ANNUAL PRECIPITATION Ellis

39.04

-99.53

8.38

Late

Hemphillian

353.57


Ellis

39.01

-99.57

8.38

Late

Hemphillian

493.40


Big Springs

43.00

-98.00

2.30

Late

Blancan

323.53


Broadwater

41.60

-102.74

3.00

Late

Blancan

288.47


Devil's Nest Airstrip

42.49

-97.43

5.00

Late

Hemphillian

676.24

Passey 2002, Damuth 2002

Mailbox Prospect

42.23

-98.07

6.00

Late

Hemphillian

507.36


Cambridge local fauna

40.52

-100.38

7.00

Late

Hemphillian

820.20


Aphelops Draw Q#1

42.20

-103.79

8.00

Late

Hemphillian

533.87


White Rock Local Fauna (CP131):

39.00

-97.00

2.00

Late

Blancan

181.26

Damuth et al. 2002

Sand Draw Local Fauna (CP118):

42.00

-100.00

2.00

Late

Blancan

275.54

Damuth et al. 2002

Deer Park Local Fauna (CP130A):

37.00

-100.00

3.00

Late

Blancan

148.43

Damuth et al. 2002

Rexroad Local Fauna (CP128C):

37.16

-100.46

3.00

Late

Blancan

589.85

Damuth et al. 2002

Santee Local Fauna (CP116F):

42.82

-97.83

4.00

Late

Blancan

646.52

Damuth et al. 2002

Honey Creek (CP116E):

42.78

-98.60

5.50

Late

Hemphillian

466.46

Damuth et al. 2002

Edson Quarry Fauna (CP123D):

39.09

-101.30

5.50

Late

Hemphillian

646.52

Damuth et al. 2002

Minium Quarry (CP126):

39.24

-100.08

6.50

Late

Hemphillian

173.49

Damuth et al. 2002

Wray Fauna (CP78):

40.04

-102.13

6.50

Late

Hemphillian

520.47

Damuth et al. 2002

Feltz Ranch Fauna, Lemoyne Quarry (CP116C):

41.17

-101.53

7.50

Late

Hemphillian

561.77

Damuth et al. 2002

165 APPENDIX D3: MOLLIC HORIZON Location Name

Latitude

Longitude

Age

NALMA

Mollic

Reference

14.65

Time Slice Early

South Bijou Hill

43.49

-99.27

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.66

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.68

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.69

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.70

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.99

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

15.00

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

15.08

Early

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

15.09

Early

Barstovian

nonmollic


Mitchell

42.20

-103.79

16.10

Early

Hemingfordian

mollic


Mitchell

42.20

-103.79

16.11

Early

Hemingfordian

nearmollic


Mitchell

42.20

-103.79

16.15

Early

Hemingfordian

nonmollic


Mitchell

42.20

-103.79

16.16

Early

Hemingfordian

nonmollic


Martin

43.14

-101.88

16.70

Early

Hemingfordian

nearmollic


Mitchell

42.19

-103.77

16.71

Early

Hemingfordian

nearmollic


Chadron

42.55

-102.86

17.67

Early

Hemingfordian

nonmollic


Chadron

42.55

-102.86

17.67

Early

Hemingfordian

nonmollic


Chadron

42.58

-103.04

17.81

Early

Hemingfordian

nonmollic


Chadron

42.58

-103.04

17.92

Early

Hemingfordian

nonmollic


Marsland

42.37

-103.30

17.93

Early

Hemingfordian

nearmollic


Marsland

42.37

-103.30

17.97

Early

Hemingfordian

nearmollic


Marsland

42.37

-103.30

18.02

Early

Hemingfordian

nearmollic


Marsland

42.37

-103.30

18.06

Early

Hemingfordian

nearmollic


Marsland

42.37

-103.30

18.10

Early

Hemingfordian

nearmollic


166 APPENDIX D3: MOLLIC HORIZON Chadron

42.58

-103.06

18.31

Early

Hemingfordian

mollic


Chadron

42.58

-103.06

18.35

Early

Hemingfordian

nearmollic


Hemingford

42.42

-103.06

18.39

Early

Hemingfordian

nearmollic


Chadron

42.58

-103.06

18.39

Early

Hemingfordian

nonmollic


Hemingford

42.42

-103.06

18.42

Early

Hemingfordian

nonmollic


Chadron

42.58

-103.06

18.43

Early

Hemingfordian

nonmollic


Chadron

42.55

-102.86

18.44

Early

Hemingfordian

nonmollic


Hemingford

42.42

-103.06

18.46

Early

Hemingfordian

nearmollic


Chadron

42.55

-102.86

18.51

Early

Hemingfordian

nonmollic


Agate

42.42

-103.73

18.61

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.63

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.65

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.66

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.70

Early

Hemingfordian

mollic


Hemingford

42.37

-103.02

18.71

Early

Hemingfordian

nonmollic


Agate

42.42

-103.73

18.72

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

18.73

Early

Hemingfordian

mollic


Hemingford

42.37

-103.02

18.77

Early

Hemingfordian

nonmollic


Agate

42.42

-103.73

18.77

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

18.79

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

18.81

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.84

Early

Hemingfordian

mollic


Agate

42.42

-103.73

18.87

Early

Hemingfordian

mollic


Eagle Crags

42.72

-103.88

18.87

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

18.88

Early

Hemingfordian

mollic


167 APPENDIX D3: MOLLIC HORIZON Agate

42.42

-103.73

18.90

Early

Hemingfordian

mollic


Eagle Crags

42.72

-103.88

18.90

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

18.95

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

19.00

Early

Hemingfordian

mollic


Mission

43.32

-100.85

19.00

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

19.01

Early

Hemingfordian

nearmollic


Mission

43.32

-100.85

19.02

Early

Hemingfordian

nonmollic


Agate

42.42

-103.73

19.03

Early

Hemingfordian

mollic


Eagle Crags

42.72

-103.88

19.03

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.06

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

19.06

Early

Hemingfordian

mollic


Mission

43.32

-100.85

19.07

Early

Hemingfordian

nonmollic


Agate

42.42

-103.73

19.08

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

19.09

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.11

Early

Hemingfordian

nearmollic


Mission

43.32

-100.85

19.11

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

19.13

Early

Hemingfordian

nearmollic


Mission

43.32

-100.85

19.15

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

19.16

Early

Hemingfordian

nearmollic


Mission

43.32

-100.85

19.17

Early

Hemingfordian

nonmollic


Mission

43.32

-100.85

19.18

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

19.20

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.22

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.26

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.28

Early

Hemingfordian

nearmollic


168 APPENDIX D3: MOLLIC HORIZON Eagle Crags

42.72

-103.88

19.30

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

19.33

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.35

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.37

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.39

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.45

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

19.46

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.47

Early

Hemingfordian

nearmollic


Agate

42.42

-103.73

19.48

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.49

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.54

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.57

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.59

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.61

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.65

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.68

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.71

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.73

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.79

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

103.88

19.82

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.84

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.87

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.90

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.94

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

19.98

Early

Hemingfordian

nearmollic


169

APPENDIX D3: MOLLIC HORIZON Eagle Crags

42.72

-103.88

20.01

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

20.04

Early

Hemingfordian

nearmollic


Eagle Crags

42.72

-103.88

20.12

Early

Hemingfordian

nonmollic


Eagle Crags

42.72

-103.88

20.22

Early

Hemingfordian

nonmollic


Norden bridge

42.79

-100.03

21.79

Early

Arikareean

nonmollic


Norden bridge

42.79

-100.03

21.82

Early

Arikareean

nonmollic


Norden bridge

42.79

-100.03

21.88

Early

Arikareean

nonmollic


Mission

43.32

-100.87

21.96

Early

Arikareean

nonmollic


Mission

43.32

-100.87

21.98

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.00

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.03

Early

Arikareean

nonmollic


Agate

42.42

-103.73

22.03

Early

Arikareean

near mollic


Mission

43.32

-100.87

22.06

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.07

Early

Arikareean

nonmollic


Norden bridge

42.42

-103.73

22.10

Early

Arikareean

nearmollic


Mission

43.32

-100.87

22.10

Early

Arikareean

nonmollic


Agate

42.42

-103.73

22.18

Early

Arikareean

near mollic


Mission

43.32

-100.87

22.19

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.22

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.25

Early

Arikareean

nonmollic


Agate

42.42

-103.73

22.27

Early

Arikareean

near mollic


Mission

43.32

-100.87

22.28

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.30

Early

Arikareean

nonmollic


Mission

43.32

-100.87

22.32

Early

Arikareean

nonmollic


Agate

42.42

-103.73

22.44

Early

Arikareean

near mollic


170

APPENDIX D3: MOLLIC HORIZON Agate

42.42

-103.73

22.55

Early

Arikareean

near mollic


Agate

42.42

-103.73

22.70

Early

Arikareean

near mollic


Agate

42.42

-103.73

22.87

Early

Arikareean

near mollic


Smiley Canyon

42.66

-103.55

23.00

Early

Arikareean

nonmollic


Merritt Dam

42.65

-100.86

9.19

Middle

Clarendonian

nonmollic


Merritt Dam

42.65

-100.86

9.36

Middle

Clarendonian

nonmollic


Merritt Dam

42.65

-100.86

9.40

Middle

Clarendonian

nonmollic


Merritt Dam

42.65

-100.86

9.98

Middle

Clarendonian

nonmollic


Mitchell

42.17

-103.73

10.00

Middle

Clarendonian

mollic


Merritt Dam

42.65

-100.86

10.02

Middle

Clarendonian

nonmollic


Olcott Hill

42.17

-103.73

10.11

Middle

Clarendonian

mollic


Olcott Hill

42.17

-103.73

10.26

Middle

Clarendonian

mollic


Valentine

42.91

-100.48

10.32

Middle

Clarendonian

nearmollic


Valentine

42.91

-100.48

10.35

Middle

Clarendonian

mollic


Valentine

42.91

-100.48

10.36

Middle

Clarendonian

nonmollic


Morland

39.37

-100.08

10.42

Middle

Clarendonian

non mollic


Olcott Hill

42.17

-103.73

10.45

Middle

Clarendonian

mollic


Olcott Hill

42.17

-103.73

10.58

Middle

Clarendonian

mollic


Big Spring Canyon

43.11

-101.94

10.60

Middle

Clarendonian

nonmollic

Damuth et al. 2002; Retallack, pers comm.

Olcott Hill

42.17

-103.73

10.73

Middle

Clarendonian

mollic


Morland

39.37

-100.08

11.10

Middle

Clarendonian

nearmollic


Valentine

42.91

-100.48

11.41

Middle

Clarendonian

mollic


Valentine

42.91

-100.48

11.43

Middle

Clarendonian

mollic


Valentine

42.91

-100.48

11.45

Middle

Clarendonian

mollic


171 Valentine

42.91

-100.48

11.46

Middle

Clarendonian

mollic


172 APPENDIX D3: MOLLIC HORIZON Valentine

42.91

-100.48

11.49

Middle

Clarendonian

nearmollic


Olcott Hill

42.17

-103.73

11.62

Middle

Barstovian

mollic


Norden quarry

42.79

-100.03

11.67

Middle

Barstovian

nearmollic


Norden quarry

42.79

-100.03

11.68

Middle

Barstovian

nearmollic


Norden quarry

42.79

-100.03

11.69

Middle

Barstovian

nearmollic


Olcott Hill

42.17

-103.73

11.71

Middle

Barstovian

mollic


Broadwater

41.55

-102.72

12.96

Middle

Barstovian

nonmollic


Broadwater

41.55

-102.72

13.07

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.05

Middle

Barstovian

nearmollic


South Bijou Hill

43.49

-99.27

14.06

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.07

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.08

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.09

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.10

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.10

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.12

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.12

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.13

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.14

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.14

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.15

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.16

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.16

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.17

Middle

Barstovian

nonmollic


South Bijou Hill

43.49

-99.27

14.18

Middle

Barstovian

nonmollic


173

APPENDIX D3: MOLLIC HORIZON Borchers Badlands north

37.18

-100.37

2.00

Late

Blancan

nearmollic



37.16

-100.37

2.12

Late

Blancan

nearmollic



37.16

-100.37

2.23

Late

Blancan

mollic



37.16

-100.37

2.23

Late

Blancan

mollic


Ainsworth

42.82

-100.56

2.25

Late

Blancan

nearmollic


Ainsworth

42.63

-99.84

2.26

Late

Blancan

nearmollic


Long Pine

42.65

-99.84

2.26

Late

Blancan

nearmollic


Ainsworth

42.65

-99.84

2.27

Late

Blancan

nearmollic



37.16

-100.37

2.37

Late

Blancan

mollic


Ainsworth

42.68

-99.98

2.44

Late

Blancan

mollic



37.16

-100.37

2.45

Late

Blancan

nearmollic


Ainsworth

42.68

-99.98

2.47

Late

Blancan

nearmollic



37.16

-100.37

2.50

Late

Blancan

mollic



37.16

-100.37

2.54

Late

Blancan

nearmollic


Broadwater

41.60

-102.76

2.61

Late

Blancan

nonmollic



37.16

-100.37

2.62

Late

Blancan

nonmollic



37.16

-100.37

2.64

Late

Blancan

nonmollic



37.18

-100.37

2.65

Late

Blancan

nonmollic



37.16

-100.37

2.73

Late

Blancan

nonmollic



37.16

-100.37

2.81

Late

Blancan

nonmollic



37.18

-100.37

2.84

Late

Blancan

nonmollic



37.18

-100.37

3.04

Late

Blancan

nonmollic



37.18

-100.37

3.27

Late

Blancan

nonmollic



37.18

-100.37

3.38

Late

Blancan

mollic



37.18

-100.37

3.45

Late

Blancan

mollic


174

APPENDIX D3: MOLLIC HORIZON Borchers Badlands north

37.18

-100.37

3.56

Late

Blancan

mollic


Crooked Creek north

37.18

-100.39

3.67

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

3.76

Late

Blancan

nonmollic


Crooked Creek north

37.18

-100.39

3.82

Late

Blancan

nonmollic


Meade

37.22

-100.48

3.82

Late

Blancan

nonmollic


Meade

37.22

-100.48

3.91

Late

Blancan

nonmollic


Crooked Creek north

37.18

-100.39

3.93

Late

Blancan

nonmollic


Meade

37.22

-100.48

4.00

Late

Blancan

nonmollic


Crooked Creek north

37.18

-100.39

4.05

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

4.09

Late

Blancan

nearmollic


Crooked Creek north

37.18

-100.39

4.10

Late

Blancan

mollic


Meade

37.22

-100.48

4.10

Late

Blancan

nonmollic


Meade

37.22

-100.48

4.17

Late

Blancan

nonmollic


Meade

37.22

-100.48

4.23

Late

Blancan

nonmollic


Crooked Creek north

37.18

-100.39

4.27

Late

Blancan

mollic


Broadwater

41.60

-102.76

4.43

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

4.43

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

4.59

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

4.69

Late

Blancan

nearmollic


Scott Lake

38.63

-100.81

4.97

Late

Blancan

nonmollic


Scott Lake

38.63

-100.81

5.07

Late

Blancan

nonmollic


Scott Lake

38.63

-100.81

5.12

Late

Blancan

nonmollic


Scott Lake

38.63

-100.81

5.23

Late

Blancan

nonmollic


Broadwater

41.60

-102.74

5.25

Late

Blancan

nonmollic


Broadwater

41.60

-102.76

5.27

Late

Blancan

nonmollic


175

APPENDIX D3: MOLLIC HORIZON Broadwater

41.60

-102.74

5.32

Late

Blancan

nonmollic


Scott Lake

38.63

-100.81

5.35

Late

Hemphillian

nonmollic


Lisco

41.52

-102.65

5.42

Late

Hemphillian

mollic


Harrisburg

41.50

-103.72

5.45

Late

Hemphillian

nearmollic


Kimball

41.20

-103.65

5.45

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

5.46

Late

Hemphillian

mollic


Broadwater

41.60

-102.76

5.56

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

5.58

Late

Hemphillian

mollic


Broadwater

41.60

-102.76

5.59

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

5.66

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

5.71

Late

Hemphillian

nonmollic


Almena

39.88

-99.69

5.71

Late

Hemphillian

mollic


Almena

39.88

-99.71

5.72

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.73

Late

Hemphillian

nonmollic


Broadwater

41.60

-102.74

5.75

Late

Hemphillian

nearmollic


Almena

39.88

-99.71

5.75

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.75

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

5.76

Late

Hemphillian

nearmollic


Almena

39.88

-99.69

5.77

Late

Hemphillian

mollic


Harrisburg

41.50

-103.72

5.78

Late

Hemphillian

nonmollic


Kimball

41.21

-103.65

5.78

Late

Hemphillian

mollic


Clayton

39.76

-100.09

5.78

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.79

Late

Hemphillian

nonmollic


Almena

39.88

-99.71

5.80

Late

Hemphillian

mollic


Clayton

39.76

-100.09

5.81

Late

Hemphillian

nearmollic


176

APPENDIX D3: MOLLIC HORIZON Crooked Creek south

37.16

-100.39

5.81

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

5.84

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.84

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

5.84

Late

Hemphillian

nonmollic


Almena

39.88

-99.71

5.84

Late

Hemphillian

mollic


Crooked Creek south

37.16

-100.39

5.87

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

5.88

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.90

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

5.93

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

5.94

Late

Hemphillian

nonmollic


Crooked Creek south

37.16

-100.39

5.94

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

5.97

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

5.99

Late

Hemphillian

nonmollic


Hays

39.15

-99.28

6.00

Late

Hemphillian

nearmollic


Crooked Creek south

37.16

-100.39

6.04

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

6.04

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

6.09

Late

Hemphillian

nearmollic


Clayton

39.76

-100.09

6.10

Late

Hemphillian

mollic


Lisco

41.52

-102.65

6.17

Late

Hemphillian

mollic


Ogalalla

41.20

-101.66

6.21

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

6.27

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

6.30

Late

Hemphillian

mollic


Ellis

39.06

-99.57

6.34

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

6.34

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

6.40

Late

Hemphillian

nonmollic


177

APPENDIX D3: MOLLIC HORIZON Broadwater

41.60

-102.74

6.41

Late

Hemphillian

nearmollic


Clayton

39.76

-100.09

6.46

Late

Hemphillian

mollic


Clayton

39.76

-100.09

6.50

Late

Hemphillian

mollic


Scott Lake

38.63

-100.81

6.50

Late

Hemphillian

nonmollic


Ellis

39.05

-99.57

6.51

Late

Hemphillian

nearmollic


Clayton

39.76

-100.09

6.54

Late

Hemphillian

mollic


Harrisburg

41.50

-103.72

6.56

Late

Hemphillian

nonmollic


Broadwater

41.60

-102.74

6.57

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

6.58

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

6.65

Late

Hemphillian

nonmollic


Ellis

39.06

-99.57

6.68

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

6.68

Late

Hemphillian

nonmollic


Hays, KS

39.15

-99.28

6.68

Late

Hemphillian

nonmollic


Clayton

39.76

-100.09

6.74

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

6.76

Late

Hemphillian

nonmollic


Ogalalla

41.20

-101.66

6.76

Late

Hemphillian

nearmollic


Clayton

39.76

-100.09

6.77

Late

Hemphillian

nearmollic


Clayton

39.76

-100.09

6.83

Late

Hemphillian

mollic


Scott Lake

38.63

-100.81

6.83

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

6.91

Late

Hemphillian

nonmollic


Ellis

39.01

-99.57

7.02

Late

Hemphillian

nonmollic


Ellis

39.13

-99.55

7.02

Late

Hemphillian

nonmollic


Hays

39.01

-99.34

7.02

Late

Hemphillian

nonmollic


Lisco

41.52

-102.65

7.03

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

7.06

Late

Hemphillian

nonmollic


178

APPENDIX D3: MOLLIC HORIZON Hays

38.88

-99.46

7.07

Late

Hemphillian

nonmollic


Hays

38.88

-99.46

7.12

Late

Hemphillian

nonmollic


Ogalalla

41.20

-101.66

7.13

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

7.14

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

7.22

Late

Hemphillian

nonmollic


Harrisburg

41.50

-103.72

7.22

Late

Hemphillian

nearmollic


Scott Lake

38.63

-100.81

7.32

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

7.36

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

7.42

Late

Hemphillian

nonmollic


Scott Lake

38.63

-100.81

7.50

Late

Hemphillian

nonmollic


Ash Hollow

41.29

-102.12

7.52

Late

Hemphillian

mollic


Ellis

39.01

-99.57

7.53

Late

Hemphillian

nonmollic


Ogalalla

41.20

-101.66

7.59

Late

Hemphillian

nearmollic


Ellis

39.04

-99.55

7.60

Late

Hemphillian

mollic


Scott Lake

38.63

-100.81

7.65

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

7.70

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

7.70

Late

Hemphillian

nonmollic


Ellis

39.04

-99.53

7.70

Late

Hemphillian

nonmollic


Ellis

39.13

-99.55

7.70

Late

Hemphillian

nonmollic


Ellis

39.01

-99.57

7.70

Late

Hemphillian

nonmollic


Ash Hollow

41.29

-102.12

7.92

Late

Hemphillian

non mollic


Ellis

39.04

-99.55

8.04

Late

Hemphillian

mollic


Ash Hollow

41.29

-102.12

8.06

Late

Hemphillian

non mollic


Lisco

41.52

-102.65

8.11

Late

Hemphillian

nearmollic


Ellis

39.04

-99.53

8.38

Late

Hemphillian

mollic


179

APPENDIX D3: MOLLIC HORIZON Ellis

39.01

-99.57

8.38

Late

Hemphillian

nearmollic


180 APPENDIX D4: VEGETATION Location Name

Latitude

Longitude

Age

Time Slice NALMA

Veg.

Reference

Marsland

42.69

-103.41

18.50

Early

Hemingfordian

1

Axelrod 1985

UCMP PB99064d

42.43

-103.40

NA

Early

Hemingfordain

2

Stromberg 2004

UCMP PB99066t

42.43

-103.07

NA

Early

Hemingfordian

2

Stromberg 2004

UCMP PB99063a

42.43

-103.79

NA

Early

Arikareean

2

Stromberg 2004

UCMP PB99102

42.76

-103.92

NA

Early

Arikareean

2

Stromberg 2004

Pliohippus Draw

42.19

-103.77

NA

Early

Hemingfordian

2

Thomasson 1983

Minimum Quarry

39.40

-100.10

9.55

Middle

Clarendonian

2

Thomasson 1991; Fox and Koch 2003

Kilgore

42.80

-101.01

13-14

Middle

Barstovian

2

MacGinitie 1962; Axelrod 1985

Beaver Co.

36.75

-100.48

11.00

Middle

Clarendonian

0

Axelrod 1985

Clarendon

34.93

-100.88

11.00

Middle

Clarendonian

3

Axelrod 1985

Gabel 1,3

43.08

-99.83

NA

Middle

Clarendonian

3

Gabel et al. 1998 Gabel et al. 1998

Gabel 9a

43.08

-99.87

NA

Middle

Clarendonian

3

Gabel 9b

43.08

-99.87

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 16

43.08

-101.72

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 17

43.13

-101.73

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 19

43.25

-99.43

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 21

43.17

-101.63

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 25-29

43.12

-101.72

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 30

43.12

-101.95

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 31-33

43.12

-102.02

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 34

43.07

-101.95

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 41

43.12

-101.70

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 46

43.07

-99.80

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 47-49

43.07

-99.80

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 50,51

43.12

-101.70

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 58

43.07

-99.85

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 59

43.12

-101.78

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 60

43.12

-102.00

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 61

42.80

-100.02

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 62

43.08

-99.83

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 63

42.78

-99.80

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 64

42.72

-99.77

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 65

42.80

-100.03

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 68

42.87

-100.53

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 69

42.98

-100.88

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 71

43.22

-101.27

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 80

42.85

-100.53

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 84

42.82

-101.72

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 87

42.88

-101.45

NA

Middle

Clarendonian

3

Gabel et al. 1998

Gabel 88

42.90

-101.43

NA

Middle

Barstovian

3

Gabel et al. 1998

Gabel 89

42.78

-100.02

NA

Middle

Barstovian

3

Gabel et al. 1998

181 APPENDIX D4: VEGETATION Gabel 90

42.67

-99.77

Gabel 91

42.72

-99.78

Gabel 104

42.68

-100.83

NA

Middle

Barstovian

3 Gabel et al. 1998

NA

Middle

Barstovian

3 Gabel et al. 1998

NA

Middle

Barstovian

3 Gabel et al. 1998 3 Gabel et al. 1998

Gabel 106a

42.68

-100.85

NA

Middle

Clarendonian

Gabel 106b

42.68

-100.85

NA

Middle

Barstovian

3 Gabel et al. 1998

Gabel 107

42.82

-100.93

NA

Middle

Clarendonian

3 Gabel et al. 1998

Gabel 124-126

42.68

-100.85

NA

Middle

Clarendonian

3 Gabel et al. 1998

Gabel 127

42.70

-100.85

NA

Middle

Barstovian

3 Gabel et al. 1998

Gabel 128

42.82

-101.08

NA

Middle

Barstovian

3 Gabel et al. 1998

Gabel 129

43.25

-99.38

NA

Middle

Clarendonian

3 Gabel et al. 1998

Gabel 144

42.90

-100.53

NA

Middle

Barstovian

3 Gabel et al. 1998

Gabel 155

42.65

-98.78

NA

Middle

Clarendonian

3 Gabel et al. 1998

Gabel 159, 160

42.53

-99.72

NA

Middle

Clarendonian

3 Gabel et al. 1998

Garden Co.

41.40

-102.35

NA

Middle

Clarendonian

2 Thomasson 1980

Poison Ivy Quarry

42.26

-98.07

10.00

Middle

Clarendonian

2 Thomasson 1983, 1990

Barstovian

1 Wheeler 1977

Hemphillian

2 Thomasson 2005

Tapir Hill

40.86

-104.00

13.00

Middle

Scout Canyon (Site 51b)

41.32

-102.16

NA

Late

Lemoyne Quarry (Site 54)

41.29

-101.88

11.30

Late

Hemphillian

2 Thomasson 2005

Scott Lake (Site 106)

38.66

-100.90

NA

Late

Hemphillian

2 Thomasson 2005

Keller

39.04

-99.33

NA

Late

Hemphillian

2 Thomasson 2005

Russ's

41.32

-102.60

8.50

Late

Hemphillian

4 Thomasson 1990

Minium

39.70

-101.14

8.00

Late

Hemphillian

4 Thomasson 1990

Site 9

39.20

-99.75

7.75

Late

Hemphillian

2 Thomasson 1990

Site 85

36.05

-100.68

7.50

Late

Hemphillian

3 Thomasson 1990

Site 50/52

41.32

-102.14

NA

Late

Hemphillian

2 Thomasson 2005

182 APPENDIX D5: CROCODILE PRESENCE/ABSENCE Location Name

Latitude

Longitude

Bottom Age

Top Age

Rockyford district

43.20

-102.50

29.30

22.70

Time Slice Early

Wounded Knee district (in part)

43.20

-102.50

29.30

22.70

Early

0

Black Bear Quarry

43.30

-100.90

19.83

16.53

Early

0

Flint Hill (Black Bear Quarries)

43.30

-100.90

19.83

16.53

Early

0

Porcupine South

43.30

-100.90

19.83

16.53

Early

0

Rosebud Formation (in part) sites

43.20

-101.40

22.70

19.77

Early

0

Wounded Knee District

43.20

-101.40

22.70

19.77

Early

0

Van Tassel South

43.00

-104.70

19.83

16.53

Early

0

Aletomeryx gracilis Quarry

42.70

-102.00

21.50

16.30

Early

1

Egelhoff Quarry; 1.6 km N of Niobrara River; Keya Paha County

42.80

-99.70

16.53

11.76

Early

Crocodile 0

0

Flattop Southwest

42.50

-104.60

29.30

22.70

Early

0

Roll Quarry - Guernsey South

42.50

-104.60

19.83

16.53

Early

0

Marsland; Dawes County

42.50

-103.30

19.83

16.53

Early

0

Harrison North

42.50

-103.50

29.30

22.70

Early

0

Rushville North

42.50

-102.50

29.30

22.70

Early

0

Box Butte County

42.40

-103.10

19.83

16.53

Early

0

Thomson Quarry; Sheep Creek-Snake Creek; Sioux County

42.20

-103.80

17.87

16.53

Early

Trojan Quarry; Sheep Creek-Snake Creek; Sioux County

42.20

-103.80

16.53

14.73

Early

East Surface Quarry; East Sinclair Draw

42.20

-103.80

16.53

14.73

Early

0

Joe Sanford Ranch (Mitchell North)

42.00

-103.70

29.30

22.70

Early

0

Goshen Hole district

41.90

-104.50

22.70

19.77

Early

0

Goshen Hole district

41.80

-104.50

29.30

22.70

Early

0

Agate Springs- Stenmylus Quarry-Harper Quarry

41.80

-103.40

22.70

19.77

Early

Harper Quarry

41.80

-103.40

22.70

19.77

Early

0

Harrison vicinity

41.80

-103.40

22.70

19.77

Early

0

Box Butte Members sites

41.80

-102.40

19.83

16.53

Early

0

Foley Quarry

41.80

-102.40

19.83

16.53

Early

0

Greenside Quarry

41.80

-102.40

19.83

16.53

Early

0

Hilltop Quarry

41.80

-102.40

19.83

16.53

Early

0

Long Quarry

41.80

-102.40

19.83

16.53

Early

0

Marsland Northwest

41.80

-102.40

19.83

16.53

Early

0

Ravine Quarry

41.80

-102.40

19.83

16.53

Early

0

Runningwater Formation sites

41.80

-102.40

19.83

16.53

Early

0

Sheep Creek Formation sites

41.80

-102.40

19.83

16.53

Early

0

Stonehouse Draw

41.80

-102.40

19.83

16.53

Early

0

Horse Creek Quarry; Laramie County

41.50

-104.70

19.83

17.87

Early

0

Bridgeport and Scotts Bluff area

41.50

-103.30

29.30

22.70

Early

0

Scotts Bluff Monument area

41.50

-103.30

29.30

22.70

Early

0

Albin Road

41.30

-104.50

29.30

22.70

Early

0

Broadwater district

41.30

-102.80

29.30

22.70

Early

0

0 1

0

183 APPENDIX D5: CROCODILE PRESENCE/ABSENCE Bridgeport Quarries

41.20

-102.40

19.83

16.53

Early

0

Martin Quarry; Quarry A

40.40

-103.90

19.83

16.53

Early

0

Trojan Quarry; Sheep Creek-Snake Creek; Sioux County

42.20

-103.80

16.53

14.73

Early

East Surface Quarry; East Sinclair Draw

42.20

-103.80

1

16.53

14.73

Early

Myers Farm; near Red Cloud; Webster County

40.10

-98.50

16.53

11.76

Middle

South Bijou Hill; Charles Mix County

43.50

-99.10

16.53

11.76

Middle

0

Agate (near); Sioux County

42.40

-103.80

16.30

10.40

Middle

1 0

0 0

Egelhoff Site; Keya Paha County

42.80

-99.70

15.60

12.93

Middle

Railway Quarry A; 6.4 km of Valentine; Cherry County

42.90

-100.50

12.93

11.67

Middle

Norden Bridge Quarry; Brown County

42.80

-100.00

12.93

11.67

Middle

Olcott Hill; Sheep Creek-Snake Creek; Sioux County

42.20

-103.80

11.76

9.04

Middle

Norden Bridge Quarry; Brown County

42.80

-100.00

12.93

11.67

Middle

Middle branch of Verdigre Creek; Knox County

42.60

-98.00

16.53

11.76

Middle

NW1/4 sec23; T.33N.,R.3W.; Knox County

42.70

-97.60

14.90

11.67

Middle

Verdigree Quarry; Knox County

42.60

-98.00

16.53

8.28

Middle

SE1/4 SW1/4 SE1/4 sec.22,T.28N.,R ?W; Antelope County

42.20

-98.10

11.76

8.28

Middle

Lowell Hillman Ranch; near Wakeeney

39.00

-99.90

11.76

8.28

Middle

Egelhoff Quarry; 1.6 km N of Niobrara River; Keya Paha County

42.80

-99.70

16.53

11.76

Middle

Horse Creek Quarry (near); Laramie County

41.50

-104.70

11.76

4.57

Middle

Hottell Ranch; Banner County

41.50

-103.90

15.60

12.93

Middle

0

Egelhoff; Keya Paha County

42.80

-99.70

12.93

11.67

Middle

0

Kuhre Quarry; Brown County

42.40

-99.90

12.93

11.67

Middle

0

Big Spring Canyon; Bennett County

43.60

-100.90

11.76

8.28

Middle

0

Gate (6 miles south of)

36.90

-100.10

11.76

8.28

Middle

1

Barth Ranch

36.70

-101.00

11.76

8.28

Middle

1

Shannon Ranch; Donley County

35.10

-100.90

11.76

8.28

Middle

1

Bromley Ranch; Donley County

35.00

-100.80

11.76

8.28

Middle

0

Rowe Ranch; Donley County

35.10

-100.70

11.76

8.28

Middle

1

MacAdams Quarry; Donley County

35.10

-100.90

11.76

8.28

Middle

0

Noble Farr Ranch; Donley County

35.00

-100.80

11.76

8.28

Middle

0

Pine Ridge (near); Shannon County

43.00

-102.60

9.04

8.28

Middle

0

Olcott Hill; Sheep Creek-Snake Creek; Sioux County

42.20

-103.80

11.76

9.04

Middle

0 0 0 0 1 1 1 1 0 0 0

0

184

APPENDIX D5: CROCODILE PRESENCE/ABSENCE Alligator Mefferdi Quarry; (George Sawyer Ranch?) near Merritt Reservoir Dam; Cherry County

42.60

-100.90

9.04

8.28

Middle

SE1/4 SW1/4 SE1/4 sec.22,T.28N.,R ?W; Antelope County

42.20

-98.10

11.76

8.28

Middle

Buis Ranch; Beaver County

36.90

-100.20

6.41

4.98

Late

0

Axtel; Randall County

34.90

-101.70

6.41

4.98

Late

0

Christian Ranch; Armstrong County

34.90

-101.50

6.41

4.98

Late

0

Smart Ranch; Lubbock County

33.50

-101.60

6.20

4.60

Late

0

Wolf Canyon; Meade County

37.00

-100.60

6.41

4.98

Late

0

Devil's Nest Airstrip; Knox County

42.60

-97.90

6.41

4.98

Late

0

Saw Rock Canyon Fauna

37.00

-100.70

6.20

2.81

Late

0

Capps Neu Pratt Local Fauna; Ellis County Port-of-Entry Pit = Arnett Local Fauna; Ellis County

36.10

-99.90

7.93

6.20

Late

36.10

-99.90

7.93

6.20

Late

Higgins Sebits Ranch Local Fauna; Lipscomb County

36.10

-100.00

7.93

6.20

Late

Box T Local Fauna; Lipscombe County

36.30

-100.10

7.31

6.41

Late

0

Optima (= Guymon); Texas County

36.80

-101.40

6.41

4.98

Late

1

Coffee Ranch (=Miami) Local Fauna; 13 km NE of Miami; Hemphill County

35.70

-100.50

6.41

4.98

Late

Goodnight fauna; Mulberry Canyon; Charles Goodnight Ranch; Armstrong County Terrell Christian Ranch; 15 km S and 12 km W of Claude; Armstrong County

35.00

-101.20

6.41

4.98

Late

34.90

-101.50

6.20

4.60

Late

Axtel Local Fauna; east wall of Woody Draw; tributary of North Cita Canyon; C.5.6 km S & 19 km E of Canyon; Randall County

34.90

-101.70

5.70

4.60

Late

Currie Ranch; Randall County

35.00

-101.70

6.20

4.60

Late

Jane's Quarry; E of Slaton; Crosby County Hereford Dump; nr Hereford; Deaf Smith County

33.40

-101.50

8.28

6.41

Late

34.80

-102.40

4.98

1.80

Late

XI Ranch; Seward County

37.20

-100.80

5.20

3.40

Late

0

Holmes Pasture; Meade County

37.00

-100.50

5.20

2.81

Late

0 0

1

1

0 0 0

0 0 0

0

0 0 0

Burnett Quarry; Knox County

33.70

-99.70

1.80

0.39

Late

Ainsworth (near); Type area of Sand Draw Fauna; Brown County

42.60

-99.80

4.98

1.80

Late

Borchers; Meade County

37.30

-100.40

4.98

1.80

Late

0

Cita Canyon; Randall County

34.90

-101.70

4.98

1.80

Late

0

Lipscomb County

36.30

-100.30

5.20

3.40

Late

0

Saw Rock Canyon; Seward County

37.00

-100.70

4.98

1.80

Late

0

0

185

APPENDIX D5: CROCODILE PRESENCE/ABSENCE Dockum (near); Dickens County

33.50

-100.80

5.20

1.64

Late

0 1

South Wichita River; Knox County

33.70

-99.70

1.80

0.39

Late

Crawfish Draw; 16km N of Crosbyton; Crosby County

33.80

-101.20

4.98

1.80

Late

Deer Park; Meade County

37.30

-100.40

4.98

1.80

Late

0

Holloman; Tillman County

34.50

-99.00

1.80

0.39

Late

0

1

186 APPENDIX E: PREDICTED SPECIES DISTRIBUTION MAPS Species distribution maps for the middle and late time slice. Refer to Figure 5 for base map explanation and Figure 7 for predicted range explanation.

187

188

189

190

191

192

193

194

195