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Journal of Vertebrate Paleontology 23(4):783–798, December 2003 q 2003 by the Society of Vertebrate Paleontology

A NEW EUCRYPTODIRAN TURTLE FROM THE LATE CRETACEOUS OF NORTH AMERICA (DINOSAUR PROVINCIAL PARK, ALBERTA, CANADA) JAMES FORD PARHAM and J. HOWARD HUTCHISON University of California Museum of Paleontology, Berkeley, California 94720

ABSTRACT—The holotype of Judithemys sukhanovi gen et. sp. nov. from the Late Cretaceous (Campanian) Dinosaur Park Formation of Alberta, Canada, has been included in four cladistic analyses. New material allows for a more complete description of this taxon. Judithemys sukhanovi is represented by 65 specimens (most very fragmentary) including one virtually complete skeleton (the holotype) and several partial shells. It differs from all other ‘‘macrobaenids’’ in the combination of wide vertebral scales, absence of central plastral fontanelles, and lack of strongly upturned peripherals. The morphology of Judithemys reiterates a suite of characters (large size, well-differentiated neurals reduced to eight, and greater overlap of the twelfth marginal scales onto the second suprapygal) common to Late Cretaceous–Paleocene ‘‘macrobaenids’’ and distinct from Early Cretaceous members. Judithemys and ‘‘Clemmys’’ backmani are close in morphology, geography, and stratigraphic position and are possibly closely related phylogenetically. A preliminary phylogenetic analysis supports the hypothesis that Judithemys is not part of the crown group.

INTRODUCTION The purpose of this paper is to formally describe and name a fossil turtle from Dinosaur Provincial Park. Well-preserved fossils of this turtle were first discovered and collected by Charles M. Sternberg in 1916 and sold to the British Museum, but were lost in the tragic sinking of the ship Mount Temple by a German surface raider later that year (Tanke et al., 2002). Over seventy years later, a nearly complete skeleton was discovered and data from that specimen were included in four cladistic analyses (Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999). The holotype and referred specimens resemble a poorly understood group of fossil turtles commonly referred to as the Macrobaenidae Sukhanov, 1964. In addition to describing and naming this taxon, we review previously published records of macrobaenids (most of which is published in Russian), setting the stage for future work on the group. A preliminary phylogenetic analysis (Fig. 1; see Phylogenetic Analysis below), based largely on Gaffney et al. (1998), supports the hypothesis that Judithemys and other macrobaenids are outside the crown group. In this study, we refer to the crown group as Cryptodira Cope, 1868b, based on the argument presented by Lee (1995:486–487; 1997:271–272). All turtles that share a more recent common history with cryptodires than with pleurodires are part of the stem taxon Cryptodiramorpha Lee, 1995. Sukhanov (1964:391) established the Macrobaenidae based on Macrobaena mongolica Tatarinov, 1959, a large Paleocene turtle from Asia. The etymology of Macrobaena refers to the large size of the type (and only known) specimen, and to the primitive North American turtle genus Baena Leidy, 1870, to which Tatarinov hypothesized Macrobaena was related. We now understand that Macrobaena is not closely related to baenids, but is a late-surviving member of an Early Cretaceous eucryptodiran radiation that includes earliest representatives of the Cryptodira (Gaffney, 1996; Shaffer et al., 1997; Gaffney et al., 1998; Brinkman and Wu, 1999; Hirayama et al., 2000). Since 1974, additional Macrobaena-like taxa from the Cretaceous of Asia have been added to the Macrobaenidae. An explicit definition of the Macrobaenidae does not exist. Sukhanov (2000:322) notes that ‘‘practically all researchers agree on the morphological uniformity of macrobaenids, but assume that this group is united only by plesiomorphic fea-

tures. . . ’’ and that ‘‘the relationships. . . to later groups of turtles is not yet clear.’’ Although Sukhanov (2000:322) provided a diagnosis of the group, no synapomorphies were given. As in Jurassic cryptodiramorphs from Europe and Asia (Eurysternidae Dollo, 1886, and Xinjiangchelyidae Nessov, 1990, in Kaznishkin et al., 1990), macrobaenids retain generalized limbs, a ligamentous attachment of the carapace and plastron, and primitive braincase characters. For this reason, macrobaenids are often conflated with the Sinemydidae Yeh, 1963 (Chkhikvadze, 1973, 1977 McKenna et al., 1987; Weems, 1988), another poorly understood group of fossil turtles, from the Early Cretaceous of China. The diagnoses and contents of the two groups are not well defined or stable. In fact, four cladistic analyses (Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999) suggest that the Macrobaenidae of Sukhanov (2000) are paraphyletic and that some macrobaenids are more closely related to Cryptodira than to other macrobaenids. Because of this, we will refer to these turtles as the ‘‘Macrobaenidae’’ in order to emphasize that monophyly has not been demonstrated. Likewise, because the monophyly, content, and definition of the Sinemydidae are also unclear, we will refer to this group as the ‘‘Sinemydidae.’’ In his most recent review of ‘‘Macrobaenidae,’’ Sukhanov (2000) recognized eight genera: (1) Macrobaena Tatarinov, 1959; (2) Kirgizemys Nessov and Khozatsky, 1973; (3) Hangaiemys Sukhanov and Narmandakh, 1974; (4) Parathalassemys Nessov and Krassevskaya, 1984; (5) Ordosemys Brinkman and Peng, 1993; (6) Dracochelys Gaffney and Ye, 1992; (7) Anatolemys Khozatsky and Nessov, 1979; (8) Asiachelys cited as ‘‘Sukhanov and Narmandakh (in press)’’ in Sukhanov (2000). The last paper has yet to appear and the description of Sukhanov (2000) does not meet the basic criteria of naming (is not explicitly indicated as intentionally new). Thus this taxon appears to be invalid and will be referred to as ‘‘Asiachelys.’’ Sukhanov (2000:317) suggested that a ninth taxon, Manchurochelys Endo and Shikama, 1942, ‘‘is probably an early representative of . . . the Macrobaenidae’’ but left it in his discussion of the Sinemydidae. Its ‘‘sinemydid’’ affinities are supported by the description of additional material and cladistic analysis of Li and Liu (1999). Three other taxa from the Early Cretaceous of East Asia have been referred to the Macrobaenidae. Bohlin (1953) described three fossil turtle species from Gansu Province, China and re-

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 23, NO. 4, 2003

FIGURE 1. A phylogeny of turtles showing the hypothesized position of Judithemys. The phylogeny is based on Gaffney (1996) and Gaffney et al. (1998) with some modifications (Appendix One). This is a strict consensus of 69 trees (CI 5 .55) with 77 steps. The numbers to the left of the branches indicate bootstrap values based on 1000 replicates, the numbers on the right are decay indices calculated with TreeRot version 2 (Sorenson, 1999). Some basal cryptodiramorphs (e.g., Kayentachelys) were included in the analysis but not figured. Similarly, the living lineages of cryptodires were considered separate operational taxonomic units in the analysis but are shown here as a simply Cryptodira. Stem-based taxa are indicated with open semicircles. Eucryptodira have an apomorphy-based definition (Gaffney, 1984). On the right, the temporal and geographic distributions of ‘‘macrobaenids’’ are given in detail. Poorly known taxa from the Early Cretaceous of East Asia (‘‘Hangaiemys’’ kansuensis et al., ‘‘Kirgizemys’’ dmitrievi, ‘‘Batoremys’’ leptis) are not shown.

ferred them to the presumably chelonioid genus Osteopygis Cope, 1870b. (O. kansuensis, O. latilimbata, and O. acutus). Nessov and Khozatsky (1978) referred them all to the ‘‘macrobaenid’’ genus Kirgizemys. Only a year later, Shuvalov and Chkhikvadze (1979) transferred O. kansuensis to Hangaiemys. However, the generic affinities of Bohlin’s ‘‘Osteopygis’’ remain uncertain; based on the arguments presented by Sukhanov (2000), we suggest that they be referred to as ‘‘Hangaiemys.’’ Kirgizemys dmitrievi Nessov and Khozatsky, 1981, is from the Neocomian sediments of the Lake Baikal Region in eastern Russia. Unfortunately, the description of K. dmitrievi lacks detailed comparison with the type species of Kirgizemys, K. exaratus. Pending a reappraisal of this taxon, we follow Skutchas (2001) and refer to this taxon as ‘‘Kirgizemys’’ dmitrievi. In contrast to Sukhanov (2000), most workers consider Dracochelys, Ordosemys, and Hangaiemys as separate from ‘‘macrobaenids’’ (Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999). We follow these workers by excluding Ordosemys and Dracochelys from our discussion of ‘‘macrobaenids.’’ However, direct observation of Hangaiemys specimens (by Parham) and translation of the original description (Sukhanov and Narmandakh, 1974) reveal that some characters of Hangaiemys (e.g., the pattern of cervical articulation) are more like Macrobaena than Dracochelys, and so we conservatively follow Sukhanov (2000) and retain Hangaiemys in our discussion of ‘‘macrobaenids.’’ In addition to the genera included by Sukhanov in his Macrobaenidae, we add the recently described ‘‘Batoremys’’ Narmandakh, 2000, from the Cretaceous of Mongolia. This turtle has not been formally described, yet has accumulated a tortured taxonomic history. Sukhanov (2000) attributes authorship to ‘‘Sukhanov and Narmandakh (in press),’’ a paper that has yet to appear. We will refer to it here as ‘‘Batoremys.’’ Some fossil turtles from North America also belong to this group. The first known North American ‘‘macrobaenid’’ is Clemmys backmani Russell, 1934, from the Paleocene of Sas-

katchewan, Canada (Figs. 1, 2). In its original description, C. backmani was inexplicably mistaken for a member of the Testudinoidea Batsch, 1788, and placed in the genus Clemmys Ritgen, 1828. This error is propagated by later workers (Brattstrom and Sturn, 1959; Ernst, 2001). Hutchison and Archibald (1986) referred it to the Macrobaenidae and so we shall refer to it as ‘‘Clemmys’’ backmani. They reported on ‘‘C.’’ backmani specimens from the Cretaceous-Tertiary boundary sediments of Montana; Holroyd and Hutchison (2002) report ‘‘C.’’ backmani from the Maastrichtian of North Dakota and Wyoming. Added to these are records of a large ‘‘macrobaenid’’ from the earliest Paleocene Denver Formation of Colorado (Hutchison and Holroyd, 2003), the middle Paleocene Goler Formation of California (McKenna et al., 1987, referred to the Sinemydidae), and the latest Paleocene of west-central North America mentioned by Hutchison (1998, 2000). Although not stated then, the latter record is from the Clarkforkian of Wyoming (Holroyd et al., 2001). A new North American ‘‘macrobaenid’’ is described below. The holotype, a nearly complete specimen (TMP 87.2.1) from the mid-Campanian (Judithian) Dinosaur Park Formation of Dinosaur Provincial Park in Alberta, Canada, is arguably the most important record of a North American ‘‘macrobaenid’’ to date. Although it was not formally described, TMP 87.2.1 is included in five analyses of cryptodiran relationships (Gaffney and Ye, 1992; Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999) and has been instrumental in our understanding of the origins of Cryptodira (Fig. 1). Institutional Abbreviations IVPP, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, People’s Republic of China; PIN, Paleontological Institute, Moscow, Russia; TMP, Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta, Canada; UALVP, Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta, Canada; UCMP, University of California Museum of Paleontology, Berkeley, California, United States of America.

PARHAM AND HUTCHINSON—NEW EUCRYPTODIRE JUDITHEMYS

FIGURE 2.

Map showing the known localities of ‘‘macrobaenid’’ turtles.

SYSTEMATIC PALEONTOLOGY TESTUDINES Batsch, 1788 CRYPTODIRAMORPHA Lee, 1995 EUCRYPTODIRA Gaffney, 1975 (sensu Gaffney, 1984) cf. MACROBAENIDAE Sukhanov, 1964 JUDITHEMYS SUKHANOVI gen. et sp. nov. Holotype TMP 87.2.1. A nearly complete but partly crushed skeleton lacking only the manus and a few partial phalanges (damaged during collection). TMP 87.2.1 was illegally collected by a private individual in 1987 and was subsequently recovered through the efforts of the Royal Tyrrell Museum of Paleontology, especially Darren Tanke. Locality and Horizon Dinosaur Provincial Park, Alberta, Canada. Dinosaur Park Formation (Judith River Group), Campanian. More precise locality data are available from the Tyrrell Museum to qualified researchers. Diagnosis Judithemys differs from Anatolemys, ‘‘Clemmys’’ backmani, ‘‘Asiachelys,’’ and Parathalassemys in the absence of a central plastral fontanelle even in subadults. Judithemys differs from Hangaiemys in having bluntly pointed versus rounded or truncated anterior and posterior lobes, a reduced number of neurals, strongly hexagonal neurals two through five, the lack of upturned peripherals, and vertebrals two through four wider than long. It differs from Kirgizemys in the presence of only eight neurals, vertebral scutes wider than long, lack of sculptural plications, distinct nuchal emargination, the lack of strongly upturned peripherals, and broader but more pointed posterior lobe of the plastron. Judithemys differs from Ordosemys in the presence of a short first thoracic rib, well formed neurals, a plastron without fontanelles, and a sella turcica that reaches the dorsum sellae. Judithemys differs from Macrobaena in the presence of a more triangular skull, ridged dentaries, the absence of an anteriorly thickened basicranium, the lack of up-

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turned peripherals, and the absence of a dorsal lip on the posterior end of the xiphiplastra. Referred Specimens TMP 66.19.39, partial cervical vertebra centrum; TMP 67.13.56, costal fragment; TMP 75.11.19, nearly complete subadult carapace and plastron lacking epiplastra and entoplastron; TMP 75.11.44, plastron lacking epiplastron and posterior tips of xiphiplastra; TMP 78.9.58, second right peripheral; TMP 79.10.119, plastron fragments of juvenile; TMP 80.8.129, costal fragment; TMP 80.16.808, third left peripheral; TMP 80.16.812, costal fragment; TMP 80.16.1021, entoplastron; TMP 81.14.23, unidentified plastral prong, probably right hyoplastron; TMP 81.19.75, second right peripheral and plastron fragments; TMP 81.26.21, dentary fragment; TMP 81.41.7, fifth left bridge peripheral; TMP 82.16.157, partial cervical vertebra centrum; TMP 82.16.319, partial epiplastron and bridge peripheral; TMP 82.19.88, costal fragments; TMP 85.58.73, partial neural; TMP 86.36.218, first right costal fragment; TMP 86.36.309, neural fragment; TMP 86.36.371, shell fragments; TMP 86.36.414, plastron fragment; TMP 86.36.418, partial left hypoplastron; TMP 86.36.531, vertebra; TMP 86.67.3 costal fragments; TMP 86.77.28, left otic region; TMP 86.77.41, left sixth costal; TMP 86.77.45 partially disarticulated but nearly complete braincase; TMP 86.77.61, neural; TMP 86.77.79, costal fragments; TMP 86.77.128, anterior peripherals (three through five?); TMP 86.78.19, costal fragment; TMP 86.78.87, costal fragment; TMP 86.116.6, shell fragments; TMP 86.118.04 costal fragments; TMP 88.106.2, nuchal fragment; TMP 89.36.171, costal fragment; TMP 89.101.6, plastron fragments; TMP 89.101.7, three peripherals; TMP 91.36.53, costal fragments; TMP 91.36.54, large sixth right peripheral; TMP 96.36.56, costal fragment; TMP 91.36.341, left seventh peripheral; TMP 91.36.814, carapace fragment; TMP 92.36.519, costal fragment; TMP 92.36.1115, seventh and eighth costal fragments; TMP 92.36.1116, right third and sixth left peripherals; TMP 93.36.1 vertebra; TMP 93.36.222, partial right hypolastron and xiphiplastron; TMP 93.36.269, partial plastron; TMP 92.36.497, fragmentary shell including some peripherals and costals; TMP 92.36.645, nearly complete carapace lacking only left posterolateral margin; TMP 92.36.1192, dentary fragment; TMP 93.150.16, left xiphiplastron fragment; TMP 95.134.2, second left peripheral; TMP 95.149.1, nearly complete carapace; TMP 96.12.187, costal; TMP 96.12.213, peripheral; TMP 97.12.136, partial left and right hyoplastra; TMP 97.36.114, epiplastra; TMP 97.80.25, vertebra fragment; TMP 99.55.47, nuchal; TMP 99.55.329, second left peripheral; UALVP 31728, nearly complete carapace. Etymology Judith, for the Campanian Judith River Group of North America, from which the holotype and all referred specimens are known; emys, for turtle; and sukhanovi, for the Russian expert on macrobaenids and other fossil turtles, Dr. Vladimir B. Sukhanov, who coined the term Macrobaenidae. DESCRIPTION Most of the following description is based on the type specimen (TMP 87.2.1) which is approximately 90% complete. Based on the degree of fusion and ossification of the skull, hyoid, and shell elements, the type individual is an adult. The fossil has undergone slight crushing as evidenced by the uneven appearance of the anterior peripherals on the right and left side and compression of the skull and mandibles. The carapace is missing peripherals eight through ten on the left sides, as well as parts of peripherals seven, eleven, and the pygal, but is otherwise intact. The appendicular skeleton includes a complete right hind limb. Most of the left hind limb is missing; only the femur and tibia remain. Both girdles are preserved and in articulation with the limbs. The caudal and cervical vertebral series are largely complete and articulated. Almost the entire skull

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FIGURE 3. The skull of Judithemys sukhanovi (TMP 87.2.1). A, Dorsal view of skull. B, Ventral view of skull. C, Lateral view of skull. D, Posterior view of skull.

(Fig. 3A–D) and hyoid apparatus are preserved (Fig. 4A). TMP 86.77.28 and 86.77.45 provide additional information about the internal morphology of the skull. Skull The skull of Judithemys sukhanovi is subtriangular in outline and relatively flat (Fig. 3A–D). Though crushed, the skull should be considered ‘‘low’’ and is comparable in depth to other ‘‘macrobaenid’’/‘‘sinemydid’’ taxa. Brinkman and Wu (1999) suggest that the skull of Ordosemys is not as low as in Sinemys Wiman, 1930, or Dracochelys. This difference is visible when the specimens are compared side by side, but is difficult to assess from the published illustrations, in which all taxa appear to have equally low skulls (which may be, in part, the result of postmortem compression). The skull of Judithemys is not as low as that of Sinemys. The bones around the right orbit are missing. The orientation of the left orbit suggests that the eyes of Judithemys were somewhat dorsally oriented, although this might be exaggerated by the crushing. The degree of temporal emargination (Fig. 3A) is less than in Sinemys and more than in Macrobaena and Hangaiemys. The cheek region (seen in Fig. 3C) is strongly emarginated, revealing the coronoid process of the attached jaw. This emargination is greater than that seen in Ordosemys, but

is less than in Sinemys. In terms of overall morphology, Judithemys is reminiscent of the extant snapping turtle Chelydra Schweigger, 1812, in its low and triangular skull with dorsolaterally facing orbits. The crushing of the skull roof, combined with a reticulate texture of the bone as well as the natural fusion of elements that can occur in older turtles, makes the identification of sutures in the type skull difficult. Gaffney (1996) and all subsequent authors code the type of Judithemys as having nasals, but these bones are not visible. Similarly, the contact of the squamosal with the parietal and postorbital (characters 18 and 19 of Gaffney, 1996) are not visible. Examination of the type skull under a microscope shows faint sutures in the anterior portion of the skull that confirm that the prefrontals are not separated by the frontals. The palate of the type skull is partially obscured by the lower jaw. The latter is firmly pressed to the skull and was not removed for this description for fear we would damage the specimen. Consequently, the fossa nasalis is not visible. Gaffney (1996) coded TMP 87.2.1 as showing a contact between the vomer and the prefrontals, a feature common to all cryptodiramorphs. This contact is undoubtedly present in Judithemys, but cannot be confirmed with the known material. Still, the majority of the ventral surface of the palate remains visible


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FIGURE 4. Judithemys sukhanovi A, Ventral view of hyoid (TMP 87.2.1). B, Posterior view of second left peripheral (TMP 91.36.54) showing thickened edge. C, Dorsal view of the right pes. Abbreviations: cbI, cornu branchiale I; cbII, cornu branchiale II; ch, corpus hyoidei; d, digit; mt, metatarsal; pl, processus lingualis.

(Fig. 3B). The shape of the vomer-palatine region is preserved in detail, even though the identification of sutural contacts is not possible. Judithemys has a primary palate, evinced by the narrow, laterally compressed vomer. On either side of the vomer, anterior to the pterygoid region, is an irregularly shaped foramen palatinum posterius. Although the exact sizes of these foramina are obscured by damage, it is possible to tell that they are approximately the same size as in Chelydra and smaller than those in Sinemys or Dracochelys. The pterygoid region is relatively well preserved. There are no interpterygoid vacuities. The anterior and lateral-most portion of the pterygoids is partially obscured by the attached jaws. However, the presence of a vertical flange on the processus pterygoideus externus is confirmed on the left side of the skull. There is no evidence for a processus trochlearis pterygoidei, as seen in pleurodires. The cryptodiramorph character of a processus trochlearis oticum is visible in the posterior region of the fenestra subtemporalis. The posteromedial portion of the pterygoid forms an ossified floor for the middle ear. The braincase is represented by TMP 87.2.1 and TMP 86.77.45. Unlike most of the rest of the skull, the sutures here are readily visible. Posteromedially, the pterygoids contact the basisphenoid and there is no ventral exposure of the prootic. This portion of the pterygoid serves as the floor for the canalis caroticus internus which is completely embedded in bone. The bone here is thick relative to that of Dracochelys (i.e., is similar to adults of Cryptodira). The morphology of the canalis caroticus internus (Figs. 5A, B, 6) is similar to the morphology described for Hangaiemys (Sukhanov and Narmandakh, 1974; Sukhanov, 2000) and Ordosemys (Brinkman and Peng, 1993). The posterior entrance to the carotids lies completely within the pterygoids and is not visible in ventral view. TMP 86.77.45 shows that each foramen anterior canalis caroticus internus is widely separated from the other and that the internal and lateral carotids are equal in width (Fig. 5B). Unlike Ordosemys, the sella turcica of Judithemys reaches the dorsum sellae (Fig. 6) and the foramen abducens is not located in the retractor bulbi pit (Fig. 6). Two large foramina are present near the border of the pterygoid and the anterior portion of the basisphenoid. Each foramen is called the foramen basisphenoidale (Meylan and Gaff-

FIGURE 5. The basicranium of Judithemys sukhanovi. A, detailed view of the basicranium of the type specimen (TMP 87.2.1). B, partially disarticulated basicranium showing the width of carotid arteries (TMP 86.77.45). Abbreviations: bo, basioccipital; bs, basisphenoid; c.c.i., canalis caroticus internus; c.c.l., canalis caroticus lateralis; f.b., foramen basisphenoidale (5carotico pharyngeale); f.p.c.c.i., foramen posterior canalis caroticus internus; pt, pterygoid.

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FIGURE 6. Oblique antero-lateral view of basisphenoid of Judithemys sukhanovi (TMP 86.77.45). Abbreviations: dor sel, dorsum sellae; f.a.c.c.i., foramen anterior canalis caroticus internus; pt, pterygoid; ret pit, retractor bulbi pit; sel tur, sella turcica.

ney, 1989; Sukhanov, 2000) or foramen carotico-pharyngeale (Gaffney, 1979; Meylan et al., 2000). Posterior to these foramina, the pterygoid increases in thickness to form a floor for the canalis caroticus internus. On the posterior portion of the basisphenoid are paired elliptical pits. Each pit begins at the posterolateral corner of the basisphenoid and trends anteromedially towards the midline. The mandible is represented by the type specimen (dorsal surface covered by the skull), a partial left dentary (TMP 81.26.21; Fig. 7A, B), and a partial right dentary (TMP 92.36.1192). Both lingual and labial ridges are present and the shape of the dentary shows that Judithemys possessed a slightly upturned beak (Fig. 3E). A similar morphology is visible in jaws referred to ‘‘C.’’ backmani (Hutchison and Archibald, 1986:10). The lingual ridge is subparallel to the labial ridge throughout the posterior portion of the dentary. Near the symphysis, however, it curves to approach the labial ridge (Fig. 7A). Hyoid The type specimen includes a well-preserved hyoid (Fig. 4A). The complete corpus hyoidei (terminology from Schumacher, 1973) articulates with two pairs of branchial horns (cornu branchiale I and II). The corpus hyoidei is well ossified. Even the anterior protuberance of the processus lingualis, a feature that generally remains cartilaginous throughout a turtle’s life except in ‘‘very late stages’’ (Schumacher, 1973:156), is visible (Fig. 4A). The widest part of the corpus hyoidei is just anterior to the attachment of the cornu branchiale I. These delicate bony rods are extremely long in Judithemys, extending posterodorsally past the cornu branchiale II. The latter structures attach to the posterior end of the corpus hyoidei and curve laterally. Vertebrae The entire cervical series is preserved in the type specimen, although some of the vertebrae are crushed. Cervical vertebrae 1–3 are ophisthocoelous (Fig. 8A). Judithemys, like Macrobaena and most Cryptodira (except Trionychoidea Gray, 1870), has a biconvex fourth cervical (Fig. 8B) that separates the opisthocoelous anterior vertebrae from the procoelous posterior vertebrae. This results in a ‘‘Walther’s formula’’ (Walther, 1922; Williams, 1950) of 1(2(3(4)5)6)7)8) as in Macrobaena (Tatar-

FIGURE 7. Judithemys sukhanovi. A, dorsal view of dentary (TMP 81.26.21); arrow indicates sinuous lingual ridge. B, Lateral view of dentary (TMP 81.26.21).

inov, 1959) and Hangaiemys (Sukhanov and Narmandakh, 1974, contra Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999). The eighth cervical has a moderately high neural spine (Fig. 8C), intermediate between the conditions in Ordosemys and Chelydra. A slight ventral keel is visible in all of the cervical vertebrae posterior to the first (Fig. 8B, C). The keel size increases posteriorly so that the ventral keel of the eighth cervical is particularly pronounced (Fig. 8C). The first thoracic vertebra and rib are entirely visible in TMP 87.2.1 (Fig. 8E). In Judithemys, the dorsal surface of the first thoracic vertebra is suturally attached to the underside of the first neural. In TMP 87.2.1, the anterior articular surface of the centrum is damaged and the natural orientation of the articular facet is ambiguous. The anterior articulation is preserved in TMP 92.36.645 (Fig. 9A) and TMP 95.149.1. In both specimens the articulator surface of the first thoracic is anteriorly directed and lacks the ventral tilt seen in Cryptodira. The first thoracic rib is shorter than one half the length of the first costal (Figs. 8E, 9A). The centra of the thoracic vertebrae shorten progressively posteriorly and are hourglass-shaped in ventral view. The costal rib heads are expanded anteroposteriorly toward the vertebrae and thoracic ribs 2–4 (costal ribs 1–3); each contacts two centra whereas thoracic rib heads 5–8 contact only one each. The following two vertebrae and their ribs arise from costal eight and form the carapacial anchor for the ilium. TMP 87.2.1 has a relatively complete caudal series; the first eleven of its caudals are closely articulated and provide an exceptional view of a ‘‘macrobaenid’’ tail. The sixth caudal vertebra is biconcave (Fig. 8D), marking the transition from a procoelous to an opisthocoelous tail as in Macrobaena (Tatarinov, 1959). Gaffney (1996) recognized the presence of a biconcave vertebral centrum in the tail of TMP 87.2.1, but Brinkman and Wu (1999) coded the Macrobaenidae as lacking a biconcave vertebra near the base of the tail. A biconcave caudal also occurs in basal testudinoids (Danilov, 1998, 2001), chelydrids (Chelydridae Gray, 1831b), and Platysternon Gray, 1831a, and is probably primitive for the clade that includes cryptodires and ‘‘macrobaenids’’ (Danilov, 1998). The caudal vertebrae of Ju-


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FIGURE 8. Aspects of the axial skeleton of Judithemys sukhanovi (TMP 87.2.1). All vertebrae are represented at the same scale, except part E as indicated. A, anterior view of first cervical vertebra. B, left lateral view of fourth cervical vertebra. C, left lateral view of eighth cervical vertebra. D, ventral view of a procoelous fifth and biconcave sixth caudal vertebra (on the left). E, ventral view of the anterior carapace with the short first thoracic rib indicated by an arrow. Abbreviations: c1, costal one; hyo, hyoplastron; p2, peripheral two; tr1, thoracic rib one.

dithemys lack chevrons (coded as present by Gaffney, 1996, and Gaffney et al., 1998). Carapace The carapace of Judithemys is longer than wide (Table 1; Fig. 10A). Peripheral bones eight through 11 are longer (Table 1) than the anterior peripherals, giving the posterior region of the carapace a flared appearance. This is exaggerated by the crushing of the anterior peripherals in the type specimen. The elongate shell of Judithemys is similar to those of other ‘‘macrobaenids’’. The anterior peripherals are not upturned as they are in nearly all other ‘‘macrobaenid’’/‘‘sinemydid’’ turtles. Although the anterior peripherals in the type appear to be upturned, forming a ‘‘gutter’’ near their lateral edge, this is an artifact of crushing. The other complete carapaces and isolated peripherals (see referred specimens) show that the most anterior peripherals have rounded lateral edges similar to those of hard-shelled sea turtles (Cheloniidae Oppel, 1811). However, some specimens of Judithemys (TMP 86.77.128, TMP 91.36.54 and 99.55.329) have thickened anterior peripherals (Fig. 4B), a character that is probably homologous to the upturned peripherals of other ‘‘macrobaenid’’ taxa. The second peripheral has a distinct pit on its posteroventral border that receives the hyoplastral buttress (Fig. 8E), a morphology shared by all ‘‘macrobaenids.’’ Peripherals three

through seven are bridge peripherals that have ligamentous attachment to the lateral denticulations of the hyoplastron and hypoplastron. The anteroventral border of the eighth peripheral has a small notch for the insertion of the hypoplastral buttress (Fig. 11). The carapace of the type is almost completely ossified and there is sutural contact between the first four costals and the peripheral series, whereas costals five through eight are only slightly separated from the peripheral series and contact only via the rib extensions. In TMP 92.36.645, all the costals are in contact with the peripherals, but in TMP 75.11.19, all but the most anterior portion of costal one are separated from the peripheral series by narrow fontanelles, a common feature in juvenile turtles. In some turtles, especially pelagic forms, the costals may not ever reach the peripherals. The shell of Judithemys is unsculptured as in Ordosemys, ‘‘Clemmys’’ backmani, Anatolemys, and Macrobaena. The nuchal (Fig. 10A) is only slightly emarginated. Early Cretaceous ‘‘macrobaenids,’’ Hangaiemys, Kirgizemys, and Ordosemys, show definite emargination, but it is less developed in Late Cretaceous and Paleocene forms (Anatolemys and Macrobaena). Among the numerous specimens referred to Judithemys is a nuchal of a juvenile. This specimen, TMP 88.106.2, has a small distinct knob on the underside of the nuchal. The function of this character is unknown, but it probably articulated with the eighth cervical vertebra as it does in living chelon-

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 23, NO. 4, 2003 ioids. This process is not visible in the adult shells (e.g., TMP 87.2.1 and TMP 95.149.1). As in Ordosemys, a slight central depression runs anteroposteriorly along the midline of the shell. In both taxa, the central depression is laterally bordered by a distinct bulge so that the dorsal outline of the carapace forms a shallow ‘‘m’’ in anterior view. The neural series (Fig. 10A) of the type specimen consists of eight neurals. The neural series of TMP 75.11.9 is incomplete, but it matches the type in preserved aspects. Judithemys sukhanovi lacks a preneural. The first neural is roughly rectangular. The remaining neurals are more hexagonal and coffinshaped with the broad end anterior. There are two triangular suprapygals. Posteriorly, the broad end of the first suprapygal meets the anteriorly directed broad end of the second suprapygal, a morphology shared by all ‘‘macrobaenids.’’ The cervical scale is typically ‘‘macrobaenid.’’ It is five times wider than long and is restricted to the nuchal bone (Fig. 10A). The vertebral scales are wider than they are long. Among ‘‘macrobaenids,’’ this character is also known in Ordosemys. In juveniles of all turtles, the vertebrals are wider than they are long, so this character could be related to age. However, as stated previously, the type specimen of Judithemys is an adult as indicated by its large size and degree of ossification. Thus, we infer that the wide vertebrals of Judithemys were maintained into adulthood. Brinkman and Peng (1993a) suggest that this feature might be primitive for Cryptodira because it also occurs in ‘‘sinemydids’’ as well as in Xinjiangchelys Yeh, 1986, and the eurysternid Plesiochelys Ru¨timeyer, 1873. Judithemys has twelve pairs of marginal scales, the typical number for cryptodires and their close relatives (Fig. 10A). The first three marginals are shorter than the rest. In the type specimen, the sulcus between the marginal and pleural scales is coincident or near the suture between the costals and peripherals. The first pleural scale encroaches upon the first two peripherals and the sulcus between the fourth pleural and the marginal scales is indicated on peripherals nine and was probably present on ten. The encroachment of the pleural scales onto the anterior and posterior peripherals is typical for all ‘‘macrobaenids’’/‘‘sinemydids’’ except Ordosemys in which the pleural scales overlap the entire peripheral series. In Judithemys, the fifth vertebral overlaps the eleventh peripheral, but the junction between this scale and the 12th marginals is located on the posterior part of the second suprapygal, and not the pygal (Fig. 10A). In this respect, it also differs from Ordosemys and Dracochelys, in which the junction is almost at the suture between the last suprapygal and the pygal and more closely resembles that of the Late Cretaceous and Paleocene

FIGURE 9. Judithemys sukhanovi. A, ventral view of anterior carapace (TMP 92.36.645) showing anteriorly directed first thoracic. B, oblique view of right inguinal region of TMP 87.2.1 showing the right femur and part of the pelvis.

TABLE 1. Measurements in cm of the carapace of Judithemys. Carapace width is at peripheral 5. The lengths (L) of carapacial elements are measured along the free margin and the height (H) is measured along the midline. Only left peripherals were measured unless indicated by R. Car., carapace; P, peripheral. TMP 87.2.1 Car. Nuchal P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 Pygal

TMP 75.11.19

TMP 95.149.1

TMP 92.36.645

UALVP 31728

L

H

L

H

L

H

L

H

L

H

38.7 6.4 3.3 4.0 4.5 4.6 4.1 5.0 4.7R 5.3R 5.2R 5.1R 5.8R —

29.3 3.7 2.6 3.0 2.3 2.0 2.0 2.5 2.9R 3.5R 3.8R 3.9R 3.8R —

31.1 6.0 1.6 3.1 4.5 3.7 3.5 3.9 3.9 4.4 4.2R — — —

27.1 2.8 2.7 2.1 1.6 1.2 1.4 1.7 2.4 3.3 3.9 — — —

43.5 9.0 3.3 4.9 — 4.1 — — 5.2 5.8 6.0 6.0 6.2 5.9

35.5 — 3.0 3.2 2.6 1.7 — 3.0 4.3 5.0 5.0 5.5 5.2 3.6

40.5 6.8 3.0R 3.7R 3.6R 4.3R 4.2R 4.9R 4.9R 5.6R 5.7R 5.4R 5.7R —

36.0 2.8 — — 2.3R 1.9R 1.8R 2.1R 3.1R 4.2R 3.5R 4.0R 4.4R —

40.3 5.8 2.9 5.0 4.4 4.9 4.4 5.3 6.1 5.5 5.8 5.5 5.2 5.4

35.5 3.9 2.1 2.6 1.8 1.5 1.8 2.1 2.9 3.7 4.2 4.8 4.7 3.8


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‘‘macrobaenids’’ Anatolemys and Macrobaena. In Hangaiemys and Kirgizemys, the junction between the fifth vertebral and 12th marginal scales also occurs on the second suprapygal, but it is more posteriorly located in these taxa than in Judithemys. Plastron The plastron is known from three specimens, the type (TMP 87.2.1, TMP 75.11.19, and TMP 75.11.44). The plastron of the type TMP 87.2.1 (Figs. 10B, 11) is complete. The other two specimens, although smaller, match this specimen in all preserved aspects. The plastron is cruciform in shape and wider than long. Its anteriorly and posteriorly directed buttresses lack sutural connections to the carapace. The hyoplastral buttress terminates in the second peripheral (Fig. 8E) and the hypoplastral buttress inserts into a notch in the eighth peripheral (Fig. 11). This pattern of shell articulation is common to all known ‘‘sinemydids’’ and ‘‘macrobaenids.’’ The epiplastra, preserved in articulation in TMP 87.2.1 and TMP 75.11.19 and by some disarticulated elements (TMP 82.16.319, TMP 97.36.1114), are slender elements that meet in the midline to form a blunt point and contact the entoplastron and hyoplastra by long scarf sutures (Hildebrand, 1974). In this respect, Judithemys more closely resembles chelonioid sea turtles and Osteopygis. The small anterior elements of the plastron (the entoplastron and epiplastra) are usually not preserved and are therefore unknown for Manchurochelys, Kirgizemys, ‘‘Asiachelys,’’ Ordosemys, and Anatolemys. In Hangaiemys, the epiplastra are also small, slender elements, but differ from those in Judithemys by forming a bluntly truncate anterior end of the plastron. The entoplastron is preserved in TMP 75.11.44, TMP 80.16.1021, and TMP 87.2.1, and is extremely small in all specimens (Table 1). It is a diamond-shaped element that is securely sutured to the anteromedial portions of the hyoplastra via coarse dentations. In Ordosemys, Dracochelys, and Sinemys, the entoplastron is only loosely attached to the hyoplastra. The lateral margin of the hyo- and hypoplastron is composed of low dentations that insert into pits in the peripherals. The hyoplastron articulates with peripherals two through five while the hypoplastron articulates with peripherals six through eight. A lateral fontanelle spans the suture between peripherals five and six. The plastron of the TMP 87.2.1 is slightly wider than it is long when measured at the points of maximum width and length (Table 2). The xiphiplastra are elongate (Table 1). In the type and the other adult plastra, the anterolateral edges of the xiphiplastra are parallel, but begin to taper just behind the femoral-anal sulcus. In this respect, they differ from the xiphiplastra of other ‘‘macrobaenids’’ except Anatolemys. In most ‘‘macrobaenids’’ the xiphiplastra do not show a break in slope in the outline of the lateral edges of the xiphiplastra. The xiphiplastron of Anatolemys differs from that of Judithemys by its greater width. TMP 75.11.19, a smaller individual, tapers more gradually, suggesting that the differences in shape are ontogenetic. The xiphiplastra of Macrobaena have a distinct lip formed by dorsal overlap of the plastral scales on their postero-dorsal surface (Sukhanov and Narmandakh, 1976:fig. 3b). None of the plastra of J. sukhanovi or ‘‘C.’’ backmani exhibit this feature. Plastral scale sulci are visible in TMP 87.2.1 (Fig. 10B) and TMP 93.36.269. The sulcus between the gular and humeral is not readily discernible but there appears to be a slight posterolaterally oriented trough traversing the epiplastron from the tip of the entoplastron. The humeral-pectoral sulcus is visible well below the entoplastron. The pectoral scale lies entirely on the hyoplastron. The abdominal scale has broadly sinuous anterior and posterior borders. A similar morphology occurs in Anatolemys. The anterior borders of the femoral and anal scales are

FIGURE 10. Judithemys sukhanovi. A, line drawing of dorsal view of carapace. B, line drawing of ventral view of plastron. Abbreviations: 1, 5, 8, neurals; ab, abdominal scale; an, anal scale; c, costal bone; cs, cervical scale; ento, entoplastron; epi, epiplastron; fe, femoral scale; hu, humeral scale; hyo, hyoplastron; hypo, hypoplastron; inf, inframarginal scale; m, marginal scale; nu, nuchal bone; p, hperipheral bone; pe, pectoral scale; ple, pleural scale; py, pygal bone; sp, suprapygal; v, vertebral scale; xiphi, xiphiplastron.

subparallel and converge anteromedially. The anterior end of the femoral-anal sulcus converges on the hyo-xiphiplastral suture medially. The presence of inframarginals is indicated by their faint medial sulci and a very faint inframarginal sulcus is indicated in raking light on the hyoplastron. The presence of four inframarginals in confirmed by TMP 93.36.269.

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 23, NO. 4, 2003 TABLE 2. Measurements in cm of the plastron of Judithemys. Two plastron widths are given; L, length; W, width along hyo-hypoplastral suture; Max. W, maximum width. Estimated lengths (e) are given for specimens that are nearly complete.

L W Max. W

TMP 87.2.1

TMP 75.11.19

TMP 75.11.44

TMP 93.36.269

23.4 23.1 26.4

20e 17.3 21.7

27e 27.9 33e

— 24.5 26.5

Limbs

FIGURE 11. The type specimen of Judithemys sukhanovi (TMP 87.2.1), a ventral view of shell and limbs.

The pectoral girdle and forelimbs are known only from the type specimen. Both sides of the pectoral girdle remain articulated to the carapace (Fig. 10). The coracoids are only just visible and cannot be described in detail. The processes of the scapulae form a perpendicular angle to one another as in Macrobaena. Although obscured, the acromion seems to lack the curved distal end present in Dracochelys. Brinkman and Peng (1993) describe a flange on the acromion that is directed towards the coracoid in Ordosemys, but this feature is lacking in Judithemys and Macrobaena. Both humeri of Judithemys are known from the type specimen. The right humerus is still articulated with the pectoral girdle. The left humerus (Fig. 12A–C) was removed and its morphology can be described in detail. It is largely complete, missing only distal fragments of the medial process and the distal trochlear surface (Fig. 12A–C). The caput forms a relatively low angle with the shaft (Fig. 12B), as in Macrobaena and cheloniid sea turtles. The medial process is mildly hypertrophied, as in powerful swimmers (trionychids, carettochelyids, and chelonioid sea turtles). The diaphysis is sinusoidal, but the curvature of the shaft is moderate in posterior view (Fig. 12B). The pelvis, though complete, is largely obscured by the posterior lobe of the plastron. Although obscured, the right ischium demonstrates that Judithemys had a large, posteriorly projecting

FIGURE 12. The limbs of Judithemys sukhanovi (TMP 87.2.1). A, dorsal view of left humerus. B, posterior view of left humerus. C, ventral view of left humerus. D, left ulna and radius of Judithemys. E, left tibia of Judithemys. Arrows indicate the position of muscle scars. D-E are at the same scale.

PARHAM AND HUTCHINSON—NEW EUCRYPTODIRE JUDITHEMYS metischial process (Fig. 9B) similar to those of Macrobaena, Ordosemys, and basal cheloniid sea turtles. Without further preparation, we could not determine whether the obturator fenestrae are confluent as in Ordosemys or separate as in Macrobaena. The right ilium is preserved in its entirety. The dorsal, posteriorly directed spine of the ilium is longer than the one illustrated for Ordosemys (Fig. 9B). Both femora are preserved in TMP 87.2.1. The left femur is still embedded in matrix. The right femur is articulated with the pelvic girdle, but not in a natural position (Fig. 9B). The head of the femur is displaced from the acetabulum and the diaphysis, just distal to the trochanters, is unnaturally pressed against the ischial rim of the glenoid. Consequently, the morphology of the head of the femur is just visible. It does not appear to be distinguishable from the morphology described for Ordosemys or Dracochelys. The trochanters are widely separated from each other but both are connected to the head of the femur by a ridge of bone. The diaphysis has an S-shaped curve and the distal articulation faces ventrally. Both tibiae are preserved in the type. The right tibia is still articulated to the fibula and astragalocalcaneum. The tibia and fibula are in contact at their proximal and distal ends. The tibia is stoutest at its proximal end and subtriangular in cross-section. The rest of the tibia is circular in cross-section; it decreases in diameter distally but expands slightly at its articulation with the astragalocalcaneum. The proximal end of the tibia bears two distinct muscle scars on its ventral surface adjacent to the spatium interosseum (Fig. 12E). The most proximal scar is a small raised tuberosity and just distal to this is a slightly depressed, roughened area. In living turtles, this area marks the origin for one of the heads of the gastrocnemius as well as the insertion point of the flexor tibialis externus (Walker, 1973). The fibula is a cylindrical element that is more slender than the tibia; its distal end is flattened and expanded. A remnant of the right astragalocalcaneum is preserved on the type, but it is weathered and lacks detail. The distal tarsals are similarly poorly preserved. An irregularly shaped fourth distal tarsal and part of the third are preserved in articulation with the metatarsals. We could not determine the presence of a centrale. The right pes is articulated (Fig. 4C), but the current position of the metatarsals probably reflects postmortem disturbance. The proximal ends of the first four metatarsals are stacked one upon another. All five metatarsals are visible in their dorsal aspects, as is the medial aspect of the first metatarsal. Metatarsals one through four are elongate, and exceed the length of the corresponding proximal phalanges. The fifth metatarsal resembles a distal tarsal in terms of morphology and position, is broad and flat, and articulates with the lateral edge of the fourth distal tarsal. Distally a protuberance articulates with the fifth proximal phalanx. This phalanx resembles a metatarsal in morphology and position. Only one phalanx of the first digit is preserved, but it is not an ungual. Digits two, three, and four preserve three phalanges including the unguals. The fifth digit is represented by two non-ungual phalanges. The phalangeal formula of the pes of J. sukhanovi was probably 2-3-3-3-3, the primitive formula for Cryptodira. PHYLOGENETIC ANALYSIS We performed a cladistic analysis based on the matrix of Gaffney et al. (1998) using the parsimony algorithm of PAUP* 4.0b3a (Swofford, 1998). In contrast to all other analyses (Gaffney, 1996; Gaffney et al., 1998; Brinkman and Wu, 1999; Li and Liu, 1999), we consider Hangaiemys and Dracochelys as separate taxonomic entities (they differ for 13 of the 40 characters; Appendix One). In addition to adding the data for Manchurochelys given by Li and Liu (1999), we change the follow-

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ing characters (Appendix One has the character coding for Judithemys, Hangaiemys, and Dracochelys): 1. Nasal bones Present 5 0; Absent 5 1. Gaffney et al. (1998) coded Judithemys as having nasals, but these bones cannot be found on the type (TMP 87.2.1), the only Judithemys specimen to preserve this region of the skull. Nasals may be present, but until this is confirmed this character should be coded as (?). Dracochelys/Hangaiemys was coded as (?) for nasals by Gaffney et al. (1998), but nasals are known in Hangaiemys (Sukhanov and Narmandakh, 1974); we change it to (0) for that taxon. 3. Prefrontal/vomer contact Contact absent 5 0; Contact present 5 1. Gaffney et al. (1998) coded Judithemys as having the prefrontal/vomer contact (1), the condition in all known cryptodiramorphs. Though likely present in Judithemys, this contact is not visible in any of the specimens, and we code it as (?). 11. Canalis caroticus internus and canalis caroticus lateralis completely embedded on bone Both canals open ventrally 5 0; Both canals embedded in bone 5 1. Gaffney et al. (1998) coded Dracochelys/Hangaiemys as having a carotid canals that open ventrally with no (or little) pterygoid flooring. Sukhanov and Narmandakh (1974) and Sukhanov (2000) show that the carotid architecture of Hangaiemys is similar to that of Judithemys. In both taxa, posterior carotid canals are ventrally enclosed by a relatively thick pterygoid. 12. Thickness of pterygoid floor of canalis caroticus internus Thin or absent 5 0; Thick 5 1. Hangaiemys is coded as (1) here (see discussion of character 11). 13. Canalis caroticus lateralis versus canalis caroticus internus Canalis caroticus lateralis equal to or larger than canalis caroticus internus 5 0; Canalis caroticus lateralis smaller than canalis caroticus internus 5 1. Gaffney et al. (1998) coded Dracochelys/Hangaiemys as (?) for this character. Several specimens of Hangaiemys (e.g., PIN 3334-1, 34, 35, 96, 97) show that Hangaiemys has the primitive state. TMP 86.77.45 shows that Judithemys also has the primitive state (0). 18. Parietal/squamosal contact Present 5 0; Absent 5 1. Gaffney et al. (1998) code the type of Judithemys (TMP 87.2.1) as showing no contact (1), the derived state, but this character is not visible in TMP 87.2.1 or any of the referred specimens. We code Judithemys as (?). Gaffney et al. (1998) also code Dracochelys/Hangaiemys as possessing the derived state, but Sukhanov (2000) shows that the squamosal contacts the parietal in Hangaiemys; therefore, we code it as (0). 19. Parietal/postorbital contact Present 5 0; Absent 5 1. We code Judithemys as (?) and Hangaiemys as (0) in our matrix (see discussion of character 18). 21–27. Cervical characters The neck of Hangaiemys was described by Sukhanov and Narmandakh (1974), but never figured. Because that paper is in Russian, the Walther’s formula and associated text were missed by most non-Russian chelonologists. As it turns out, the neck of Hangaiemys is similar to that of Judithemys and we recoded characters 21–25 and 27 accordingly. Neither of us has seen the neck of Hangaiemys first hand, but photographs supplied by Sukhanov and Danilov confirm our coding. 31. Chevrons Well developed and present on nearly all caudals 5 0; Small to absent (if present, only on a few posterior caudals) 5 1. Gaffney et al. (1998) code TMP 87.2.1 as having chevrons, but we did not find them and so code Judithemys as (1) for this character. 32. First thoracic rib Extends to peripherals or nearly so and lies behind the tip of the axillary buttress of the plastron 5 0; Extends less than halfway across the first costal 5 1. Gaffney et al. (1998) code Dracochelys/Hangaiemys as (0), but Sukhanov and Narmandakh (1974) describe the derived condition for Hangaiemys.

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 23, NO. 4, 2003 DISCUSSION

The result of our analysis (Fig. 1) is not much different from that of Gaffney et al. (1998). The only difference in our consensus tree is the more crownward position of Hangaiemys. Cryptodira, Judithemys, and Hangaiemys form a well supported monophyletic group (Fig. 1). This clade can be diagnosed by one unambiguous synapomorphy, the presence of strong ventral processes on the cervical vertebrae. Despite the fact that the Judithemys-Hangaiemys-Cryptodira grouping is the best supported clade in our analysis (bootstrap 5 91; decay index 5 5), we refrain from naming it here because the monophyly of Cryptodira exclusive of Judithemys and Hangaiemys has a lot less support (bootstrap 5 77; decay index 5 5). When trees with one additional step are considered, Judithemys, Hangaiemys, and Cryptodira form an unresolved polytomy. Consequently, we cannot rule out the hypothesis that some ‘‘macrobaenids’’ are within the crown group (e.g., Brinkman and Wu, 1999) without a more detailed phylogenetic analysis including a broader sampling of ‘‘macrobaenids’’ and generic-level basal cryptodires (Parham and Danilov, unpubl. data). Judithemys closely resembles other taxa referred to ‘‘Macrobaenidae’’ and we compare them here. Within ‘‘macrobaenids,’’ Judithemys differs from Anatolemys and ‘‘Clemmys’’ backmani in the absence of a central plastral fontanelle even in subadults. Judithemys differs from Hangaiemys and ‘‘Batoremys’’ in having bluntly pointed anterior and posterior lobes versus rounded or truncated, the lack of strongly upturned peripherals, a reduced number of neurals, strongly hexagonal neurals 2–5, and vertebrals 2–4 wider than long. It resembles Kirgizemys in the absence of a central fontanelle but differs in the presence of only eight neurals, vertebral scutes wider than long, distinct nuchal emargination, the lack of strongly upturned peripherals, and broader but more pointed posterior lobe of the plastron. Although Macrobaena was redescribed by Sukhanov and Narmandakh (1976), the type and only specimen could use additional description. Restudy of Macrobaena (JFP, pers. obs., 1999) revealed previously unknown aspects of its morphology. Unlike Judithemys, Macrobaena has flat, crushing dentaries as well as an unusual basicranium. In Macrobaena, the portion of the basicranium that includes the anterior basisphenoid is extremely thick. Judithemys differs from Macrobaena in the presence of a more triangular skull, ridged dentaries, the absence of a anteriorly thickened basicranium, the lack of upturned peripherals, and the absence of a dorsal lip on the posterior end of the xiphiplastra (see Sukhanov and Narmandakh, 1976:113). Hutchison (in Gaffney, 1996) suggests that TMP.87.2.1 (the type of Judithemys sukhanovi) represent a species close to ‘‘C.’’ backmani. ‘‘Clemmys’’ backmani was originally described from the Paleocene of North America (Fig. 2) based on a partial shell (Russell, 1934), but is now known from several more complete but undescribed specimens (Holroyd and Hutchison, 2002). Both ‘‘C.’’ backmani and Judithemys have ridged dentaries. Among ‘‘macrobaenids,’’ both taxa are unusual for having peripherals that lack thickened edges or are not upturned in some individuals. Like J. sukhanovi, ‘‘Clemmys’’ backmani is polymorphic with respect to this character (UCMP 136032, UCMP 136034). Judithemys differs from ‘‘C.’’ backmani in the absence of hyo-hypoplastral fontanelles, smaller size, thicker shell, the shape of the skull, and other features. Because of the few diagnostic characters, the high potential for homoplasy within the ‘‘Macrobaenidae,’’ and poor understanding of the outgroup condition for character polarization, we are reluctant to hypothesize other monophyletic groups within ‘‘macrobaenids’’ at this time. However, we can recognize two types of ‘‘macrobaenids’’ based on size, stratigraphy, and morphology. The Early Cretaceous ‘‘macrobaenids’’ share characters that are absent in later taxa. For example, the shape

of the neurals in these taxa and ‘‘sinemydids’’ are not the same as in later ‘‘macrobaenids.’’ In ‘‘sinemydids,’’ the anterior neurals are subrectangular (quadrangular to very slightly hexagonal to octagonal). Narrow and roughly subrectangular neurals also occur in the outgroup Xinjiangchelyidae (Peng and Brinkman, 1993) and are here regarded as primitive for the clade that includes ‘‘sinemydids,’’ ‘‘macrobaenids,’’ and Cryptodira. Subrectangular neurals are retained in Hangaiemys and the first couple of neurals in Kirgizemys. Late Cretaceous and Paleocene ‘‘macrobaenids’’ have the derived condition of well-formed hexagonal neurals two through eight, a more proximal position of the vertebral five-12th marginal sulcus and larger size (carapace length .40 cm versus ,30 cm). The largest Judithemys specimen (TMP 95.149.1) is 43.5 cm in carapace length. Anatolemys (60–70 cm), ‘‘C.’’ backmani (50–60 cm), and Macrobaena (55 cm) achieved even greater size. Judithemys in the Judith River Group The uppermost Judith River Group of southern Alberta is interpreted as a coastal lowland deposit with increasing marine influence with time (Brinkman, 1990; Eberth, 1990), a transgression that culminates in the Bearpaw Sea. Judithemys is one of nine recognized generic-level turtle taxa from the upper Judith River Group (Hutchison et al., 1998). The remaining eight include three paracryptodires (Paracryptodira Gaffney, 1975): Boremys Lambe, 1906, Plesiobaena Gaffney, 1972, Neurankylus Lambe, 1902, and five cryptodires: Adocus Cope, 1868a, Basilemys Hay, 1902, the trionychids Apalone Rafinesque, 1832, and Aspideretoides Gardner, Russel and Brinkman, 1995, and an unnamed chelydrid. Altogether, these taxa represent a typical Late Cretaceous assemblage of cryptodiramorphs. In North America, the Late Cretaceous marks a transition from a chelonian fauna that is largely paracryptodiran to one that is dominated by eucryptodires in the Cenozoic. This did not happen suddenly. Instead, lineages of non-marine cryptodires make their first appearance at different times throughout the Late Cretaceous (Hirayama et al., 2000; Hutchison, 2000). The first group of non-marine cryptodires to appear are the Trionychidae Fitzinger, 1826 (softshells). Although known from Early Cretaceous deposits of Central Asia, they do not appear in North America until the beginning of the Late Cretaceous Cenomanian (;97 Ma). The trionychids are closely followed by the most ancient snapping turtles (Chelydridae) in the Turonian (;92 Ma). The next to appear are two clades of the trionychoids, the aquatic Adocidae Cope, 1870a, and terrestrial Nanshiungchelyidae Yeh, 1966, in the Coniacian-Santonian (;87 Ma). The last cryptodire lineage to appear in the Cretaceous is the Kinosternia Gaffney and Meylan, 1988 (includes the living Kinosternidae Agassiz, 1857). Kinosternian turtles make their first appearance in the Campanian (;84 to 71 Ma) Kaiparowits Formations (Hutchison et al., 1998). Judithemys sukhanovi, possibly not within Cryptodira, is part of this staggered pattern of appearance of eucryptodires. The appearing lineages can be divided into two categories, those without any more ancient relatives (kinosternians and chelydrids) and those with more ancient relatives in Asia (trionychids, nanshiungchelyids, adocids). The latter groups are probably immigrants from Asia, reflecting a close proximity of Asian and North American landmasses in the Late Cretaceous (Smith et al., 1994). This pattern of interchange between Asia and North America is mirrored in other clades, including lizards (Alifanov, 2000) and dinosaurs (Russell, 1993). Judithemys sukhanovi is currently the oldest described ‘‘macrobaenid’’ in North America, although undescribed specimens from the Turonian of the Canadian Arctic (Tarduno et al., 1998; Brinkman, pers. comm.) as well as the Aptian-Albian of Utah and Alberta (Hirayama et al., 2000) may represent earlier oc-

PARHAM AND HUTCHINSON—NEW EUCRYPTODIRE JUDITHEMYS currences. Consequently, Judithemys and the North American ‘‘macrobaenids’’ should be viewed as part of a larger invasion of eucryptodires from Asia, the details of which should be sought in the pre-Campanian sediments of Asia and North America. A Reconstruction of Judithemys The morphology of Judithemys clearly suggests a wholly aquatic turtle. Its locomotory specializations include the morphology of the humerus, the glenoid neck of the scapula, and the long phalanges of the pes. All of these limb features promote the idea that Judithemys was a powerful swimmer. The low, hydrodynamic shape of the carapace supports this assessment. An ancillary line of evidence is the cruciform plastron that would allow increased leg mobility. However, we should be careful not to infer a simple adaptive significance for this feature, as other explanations are possible. For example, a reduced plastron allows for a greater surface area for cutaneous respiration, a phenomenon that has been known in turtles since 1886 (Gage and Gage, 1886). The strong similarity of the skull to the living snapping turtle Chelydra implies a similar feeding ecology, but lack of bowing of the thoracic ribs does not suggest the powerful strike and gulp behavior of Chelydra. The sharp labial ridges of the dentary demonstrate that Judithemys was not durophagous and the presence of medial ridges on the dentary suggests an omnivorous to herbivorous diet. It is important to note that many of the similarities with Chelydra are largely shared plesiomorphies, but that does not preclude them from being ecologically significant. Considering its entire morphology, we hypothesize that Judithemys was a strong swimmer with an omnivorous to herbivorous diet. CONCLUSIONS Judithemys is the most complete North American ‘‘macrobaenid’’ known thus far and provides a basis for comparison with New and Old World taxa. The referral of the Late Cretaceous Judithemys and ‘‘Clemmys’’ backmani to the ‘‘Macrobaenidae’’ reveals a hidden diversity of derived North American ‘‘macrobaenids.’’ Geography, age, and the morphology of the peripherals and dentaries suggest that Judithemys and ‘‘Clemmys’’ backmani may be closely related, although they differ in other significant features. The phylogenetic position of the less complete or undescribed Wyoming and California ‘‘macrobaenids’’ is unknown, although their large size is consistent with younger ‘‘macrobaenids.’’ Because Judithemys and the other ‘‘macrobaenids’’ are clustered at the base of the crown clade, Cryptodira, their interrelationships are important for understanding character polarization for the crown group. Despite their relevance to the discussion of cryptodiran interrelationships, no ‘‘macrobaenids’’ and only one ‘‘sinemydid’’ were included in a recent analysis of cryptodiran relationships (Shaffer et al., 1997; Hirayama et al., 2000). Future investigations into basal cryptodiran relationships must consider the known suite of ‘‘sinemydids’’/‘‘macrobaenids.’’ ACKNOWLEDGMENTS Vladimir B. Sukhanov and Igor Danilov deserve many thanks for facilitating JFP’s visits to Russia to examine comparative material. We also thank Donald Brinkman of the Royal Tyrrell Museum for making TMP 87.2.1 and conspecific material available to JHH, for providing encouragement and good advice to JFP along the way, and for facilitating JFP’s visit to the TMP to see new material of Judithemys as well as ‘‘sinemydids’’/‘‘macrobaenids’’ from China (including unpublished materials). Kevin Padian of the UCMP is thanked for his un-

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wavering support of turtle research and helpful comments. Pat Holroyd (UCMP) reviewed an earlier version of the manuscript. Jane Mason and Mark Goodwin (UCMP) helped prepare TMP 87.2.1. The staff at the TMP are thanked for their efforts collecting, preparing, and curating the specimens described here. Darren Tanke provided JFP with the tragic history of the Mount Temple and its cargo of precious turtles. This study was funded by the University of California Museum of Paleontology, a University of California Vice Chancellor’s Graduate Fellowship (to JFP), a National Science Foundation Graduate Fellowship (to JFP), and a grant from the Sam Welles’ fund (to JFP). Travel funds for JHH were provided by the Annie M. Alexander Endowment to the UCMP. This is UCMP Contribution no. 1779. LITERATURE CITED Agassiz, L. 1857. Contributions to the Natural History of the United States of America, Vol. 1. Little, Brown and Company, Boston, 452 pp. Alifanov, V. R. 2000. The fossil record of Cretaceous lizards from Mongolia; pp. 368–389 in M. J. Benton, M. A. Shishkin, D. M. Unwin, and E. N. Kurochkin (eds.), The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press, Cambridge. Batsch, A. J. G. C. 1788. Versuch einer Anleitung, zur Kenntniß und Geschichte der Thiere und Mineralien. I. Akademische Buchhandlung, Jena, 528 pp. Bohlin, B. 1953. Fossil reptiles from Mongolia and Kansu. Report from the scientific expedition to the north and western provinces of China under the leadership of Sven Hedin. The Sino-Swedish Expedition, VI. Vertebrate Palaeontology 6:1–113. Brattstrom, B. H., and A. Sturn. 1959. A new species of fossil turtle from the Pliocene of Oregon, with notes on other fossil Clemmys from western North America. Bulletin of the Southern California Academy of Sciences 58(2):65–71. Brinkman, D. B. 1990. Paleoecology of the Judith River Formation (Campanian) of Dinosaur Provincial Park, Alberta, Canada: evidence from vertebrate microfossil localities. Palaeogeography, Palaeoclimatology, Palaeoecology 78:37–54. ———, and J.-H. Peng. 1993. Ordosemys leios, n. gen., n. sp., a new turtle from the Early Cretaceous of the Ordos Basin, Inner Mongolia. Canadian Journal of Earth Sciences 30:2128–2138. ———, and X.-C. Wu. 1999. The skull of Ordosemys, an Early Cretaceous turtle from Inner Mongolia, P. R. of China, and the interrelationships of the Cryptodira (Chelonia, Cryptodira). Paludicola 2(2):134–147. Chkhikvadze, V. M. 1973. [Tertiary Turtles from the Zaisan Depression]. Izdatel’stvo ‘Metsniereba,’ Tbilisi, 101 pp. ——— 1977. [Fossil turtles of the family Sinemydidae]. Soobscheniya AN Gruzinskoi SSR 82:265–270. Cope, E. D. 1868a. On some Cretaceous Reptilia. Proceedings of the Academy of Natural Sciences of Philadelphia 1868:233–242. ——— 1868b. On the origin of genera. Proceedings of the Academy of Natural Sciences of Philadelphia 1868:242–300. ——— 1870a. On the Adocidae. Proceedings of the American Philosophical Society 11:547–553. ——— 1870b. Synopsis of the extinct Batrachia, Reptilia and Aves of North America. Part I. Transactions of the American Philosophical Society 14:1–252. Danilov, I. 1998. Phylogenetic relationships of platysternid turtles. Third Asian Herpetological Meetings Abstract: 14. ——— 2001. Morphology of the primitive Testudines (Cryptodira: Testudinoidea) and the problem of relationships of Cryptodira; pp. 81– 83 in N. B. Ananjeva, I. S. Darevsky, E. A. Dunayev, N. N. Iordansky, S. L. Kuzmin, and V. F. Orlova (eds.), Problems in Herpetology. Proceedings of the 11th Meeting of the Nikolsky Herpetological Society. Puschino, Moscow. Dollo, L. 1886. Premie`re note sur les Che´loniens du Bruxellien (Eoce`ne moyen) de la Belgique. Bulletin du Muse´e Royal d’Histoire Naturelle de Belgique 4:75–100. Eberth, D. A. 1990. Stratigraphy and sedimentology of vertebrate microfossil sites in the uppermost Judith River Formation (Campanian), Dinosaur Provincial Park, Alberta, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 78:1–36. Endo, R., and T. Shikama. 1942. Mesozoic reptilian fauna in the Jehol

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 23, NO. 4, 2003 APPENDIX 1 Codings for Judithemys, Hangaiemys, and Dracochelys. An * indicates a coding that is different from Gaffney et al. (1998). Justifications for these changes are given in the text.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40.

Judithemys

Hangaiemys

Dracochelys

?* 1 ?* 0 1 1 1 1 1 1 1 1 0* 0 ? 1 1 ?* ?* 1 1 1 1 1 1 0 1 0 1 1 1* 1 0 1 1 1 1 1 1 1

0* 1 1 1 1 1 1 1 1 1 1* 1* 0* 0 ? 1 1 0* 0* 1 1* 1* 1* 1* 1* 0 1* 0 ? ? ? 1* 0 1 1 1 1 1 1 1

? 1 1 1 1 1 1 1 1 1 0 0 ? 0 ? 1 1 1 ? 1 0 0 0* 2 2 0 ? 0 ? ? ? 0 0 1 1 1 1 1 1 1