ABSTRACT - The eggshell material from some Late Cretaceous Peruvian ... that the same oospecies exists in these three areas, in Late Cretaceous deposits.
LATE C R E T A C E O U S P E R U V I A N EGGSHELLS AND THEIR RELATIONSHIPS WITH L A U R A S I A N A N D E A S T E R N GONDWANIAN MATERIAL MONIQUEVIANEY-LIAUD, KARLHIRSCH¢, ASHOKSAHNI & BERNARDSIGI~ VIANEY-LIAMD M., HIRSCH K., SAHNI A. & SIGI~ B. 1997. Late Cretaceous Peruvian eggshells and their relationships with Laurasian and Eastern Gondwanian material. [Coquilles d'oeufs du Cr~tac~ sup~rieur du P~rou, et leurs relations avec du materiel laurasiatique et est-gondwanien]. GEOBIOS, 30, 1: 75-90. Villeurbanne, le 28.02.1997. Manuscrit d~iposd le 14.06.1995; accept~ ddfinitivement le 06.09.1995. ABSTRACT - The eggshell material from some Late Cretaceous Peruvian sites is reevaluated in light of the results of eggshell research in the last years. As a preliminary step, a new oospecies is first described from the Aix Basin (France): Megaloolithus pseudomamillare. The eggshells from the Bagua Basin Peru are divided into six types [1, Dinosauroid spherulitic type, Tubospherulitic morphotype and Angusticanaliculate pore system (M. pseudomamillare); 2, Dinosauroid spherulitic, undetermined morphotype; 3, Ornithoid type, Ratite morphotype, Angusticanaliculate; 4, Ornithoid type, Ratite morphotype; 5, Ornithoid type, Ratite morphotype or dinosauroid type, Angustispherulitic morphotype; 6, ? Geckonoid type]. Because of presumable loss of the main part of the material, it was not possible to make additional studies on the eggshells from Laguna Umayo. We can only assess that the tuberculate fragments described by Kerourio & Sigd (1984) belong to Megaloolithus, and that the type 2 of this locality could be the same as the type 5 of the Bagua basin. The family Megaloolithidae is thus recorded in Europe, India and South America; it seems that the same oospecies exists in these three areas, in Late Cretaceous deposits. The available biochronological data discussed here support the tentative correlation of the Umayo Formation with the Fundo el Triunfo Formation. KEYWORDS: EGGSHELLS, MICROSTRUCTURES, REPTILIA, LATE CRETACEOUS, SOUTH AMERICA, EUROPE, INDIA. Rt~SUMt~ - Les restes de coquilles d'oeufs de gisements Cr~tac4 terminal du P~rou sont rddvalu~s h la lumi~re des ~tudes r4centes sur les coquilles d'oeufs de reptiles. En pr4alable, une nouvelle esp~ce est d~crite du bassin d'Aix en Provence (France): Megaloolithus pseudomamillare. Les coquilles du bassin de Bagua sont r~parties entre six types: [1, type Dinosauroide sph~rulitique, morphotype Tubosph~rulitique et Angusticanalicul~ (M. pseudornamillare); 2, type Dinosauro~'de sph~rulitique, morphotype ind~termin~; 3, type Ornithoide, morphotype Ratite, Angusticanalicul~; 4, type Ornitho~de, morphotype Ratite; 5, type OrnithoYde, morphotype Ratite ou type Dinosauro~de, morphotype Angustisph~rulitique ; 6, type ?Geckono~de]. Du fait qu'une grande partie du materiel de Laguna Umayo n'ait pu ~tre jusqu'h pr4sent retrouvde, il n'a pu ~tre r~examin4. On peut seulement affirmer, au vu des figurations de Kerourio & Sig~ (1984) que leur type tubercul~ appartient au genre Megaloolithus, et que leur type 2 pourrait ~tre identique au type 5 du bassin de Bagua. La famille Megaloolithidae est h prdsent document~e en Europe, Inde et Am~rique du Sud; il semble aussi que la m~me esp~ce existe dans ces trois r~gions au Cr~tac4 sup4rieur. Les informations biochronologiques disponibles discut~es dans ce travail appuient l'hypoth~se de la corrdation temporelle entre les Formations Umayo et Fundo el Triunfo. MOTS-CLI~S: COQUILLES D'OEUFS, MICROSTRUCTURES, REPTILES, CRI~TACt~ SUPI~RIEUR, AMI~RIQUE DU SUD, EUROPE, INDE.
INTRODUCTION T h e f i r s t alleged d i n o s a u r eggshell m a t e r i a l f r o m Mesozoic s e d i m e n t s of P e r u h a s b e e n discovered a t L a g u n a U m a y o site, in t h e a r e a of t o w n of P u n o (Andes of S o u t h e r n P e r u ) (Sig6 1968). T h e s t u d y a n d i d e n t i f i c a t i o n of t h e r e p o r t e d m a t e r i a l w a s performed by Raymond Dughi and Francois
Sirugue, M u s e u m of N a t u r a l H i s t o r y of Aix-enProvence, F r a n c e . T h e l a t e C r e t a c e o u s age of t h e eggshell-bearing formation was previously stated ( G r a m b a s t et al. 1967) on t h e b a s i s of a c h a r o p h y te a s s o c i a t i o n f r o m t h e s a m e level: t h i s association w a s c o n s i d e r e d to be e q u i v a l e n t to t h a t formerly described from the regional Southern P e r u v i a n u n i t Vilquechico F o r m a t i o n . T h e age of
76 the latter was recognized as Late Cretaceous by Newell (1949), agreed by Grambast (op. cir.), then followed by subsequent authors (e.g. Portugal 1974; A u d e b a u d et al. 1976). Additional eggshell material was obtained later (B. Sig~ 1980) from the same Laguna Umayo site. Together with the previous material it contributed to support a first descriptive account of the two recorded structural types (Kerourio & Sig~ 1984). Except for a fragment of a rather large bone, of presumable dinosaur histology (Sig~ 1968, note 10), no typical dinosaurian remains have been found among the small sized vertebrate bone and tooth fragments associated with the eggshells. The 1984 and 1985 survey of various fossiliferous outcrops in the Late Cretaceous and Early Tertiary formations of the Bagua Basin (Andes of Northern Peru) yielded an eggshell material in the bottom levels of local red-beds. Dinosaurian bone remains have been reported from the same beds (Mourier et al. 1986). A preliminary account of these eggshells, with precise data on the localities, has been given in the general survey report (Hirsch in Mourier et al. 1988). The vertebrate-bearing formation received the name of Fundo E1 Triunfo Formation (Naeser et al. 1991). It is considered Late Campanian to Maastrichtian in age according to its robust biostratigraphic record. There is no discussion as regards the assumed age of the Fundo E1 Triunfo Fro. In contrast, that of the vertebrate-bearing level at Laguna Umayo, previously accepted as Late Cretaceous (e.g. Clemens et al. 1979), is questioned. According to its presumed correlation with the Vilquechico Fro., the age of the latter itself has been questioned in a confusing discussion (Van Valen 1988), whereas the question actually concerns the evolutionary stage of the mammals associated with the eggshells at Laguna Umayo. The scarce roammal fauna reported until now from the classic site (Sig~ 1972) remains difficult to compare with other faunas of the Late Cretaceous - Early Tertiary period in South America, since there are no closely comparable elements among them. On the geological aspect, a clarification has been provided by the revision of the now Vilquechico Group in its typical section, with detailed lithological, sedimentological, and fossil contents (Jaillard et al. 1993). Accordingly
its age is Late Cretaceous, ranging from presumed Coniacian for the Lower Vilquechico Fro. to Maastrichtian for the Upper Vilquechico Fm. In correlation discussions based on revised extensive Andean charophyte associations, the local vertebrate-bearing Umayo Fro. is suggested as a nearby lateral equivalent of the Upper Vilquechico Fro. third minor sequence. The scarce, but important eggshell material of 32 fragments from the Bagua basin has been described by Hirsch in Mourier et al. 1988. The results of eggshell research of the last years (Mikhailov 1991; Mikhailov et a1.,1994; Sahni et al. 1994; Hirsch & Quinn 1990; Hirsch 1994; Vianey-Liaud et al. 1987, 1994; Zhao 1979) allow us to assign the dominant type of eggshell of the B a g u a Basin (21 fragments of the large mamillae type) to a new species of the genus Megaloolithus described below on eggshells from France and on referred eggshell material from India. The other eggshell types from the Bagua basin, represented only by one or two fragments, could be related to dinosaur spherulitic (dinosaurian origin), ornithoid-ratite (either dinosaurian or avian origin), or gecko morphotypes. The surfaces and sections, in radial views, (fresh and thin) of the eggshells are observed under binocular microscope, or by SEM. Some eggshell material is listed in the Hirsch's catalogue (HEC), the other in the Universit~-MontpellierII collections, with the reference of their locality (Les Br~gui~res = LBR; Taklil = TAK1; LU = Laguna Umayo).
SYSTEMATIC P R E L I M I N A R Y MEGALOOLITHUS VIANEY-LIAUD ET AL. 1994 IMPROVED DATA Zhao (1979) established, based on only some eggshell fragments from France, the parataxonomic family "Megaloolithidae". Erben (1970) established a A-type and C-type for these eggs, which were classically considered to be the eggs of "Hypselosaurus'. Mikhailov (1991), also based on
FIGURE 1 - 1,2,3. Megaloolithus pseudomamillare nov. sp., Les Br~gui~res locality, Aix en Provence Basin, France. 1, five fragments from LBR5, drawings of fresh fractures [x 12,5]. 2, LBR3-A, Type thin section [x 50]. 3, diagrammatic figuration of the histostructure and ornamentation. 4. Diagrammatic figuration of the histostructure and o r n a m e n t a t i o n of M, pseudomamillare from B a g u a Basin, Peru. 5. Diagrammatic figuration of the histostructure and ornamentation ofM. pseudomamillare from Takli 1 locality, central India. 6. Diagrammatic figuration of the histostructure and o r n a m e n t a t i o n of M. pseudomamillare from La Cardeline locality, Aix Basin, France. 7. Thin section ofM. pseudomamillare from Takli 1 locality, central India, TAKI-2 [x 40]. 1,2,3. Megaloolithus pseudomamillare nov. sp., localit~ Les Br~gui~res, Bassin d'Aix-en-Provence, France. 1, cinq fragments du prgl~vement LBR5, sch~mas de fractures fra~ches. 2, LBR3-A, lame mince Type. 3, reprgsentation schgmatique de l'histostructure et de l'ornementation de cette esp~ce. 4. Representation schgmatique de l'histostructure et de l'ornementation de M. pseudomamillare provenant du bassin de Bagua, Peru. 6. Reprdsentation sch~matique de l'histostructure et de l'ornementation de M. pseudomamillare provenant du site de La Cardeline, bassin d'Aix, France. 7. Lame mince de M. pseudomamillare provenant du site de Takli 1, centre de lTnde.
77
1
~i~
~~'
..~
5
~
~
6
78 only a few fragments had the following diagnosis for them: tubospherulitic morphotype, tubocanaliculate pore system, sculptured surface (compactituberculate ornamentation), subspherical eggs, "thick" eggshell (1,5-2,5 mm, possibly more). However, the eggshell material of France is more diverse in structural types as noted earlier by Dughi and Sirugue (1958), Williams et al. (1984), P e n n e r (1985), Vianey-Liaud et al. (1987), Dauphin (1990) and Vianey-Liaud et al. (1994). Thus "Hypselosaurus" cannot b e linked to both of these different morphotypes.
lescing nodes; limits of the short fan-shaped units not always traceable, generally clear in the inner half or third of the shell thickness; growth striations often continuing across adjacent units, often horizontal at the base of the units and becoming more and more convex upwards; pore canals generally straight with a few of them being oblique (figure); shell thickness from 1,03 to 1,6 ram.
Vianey-Liaud et al. (1994) reviewed the French eggshell material and added a few characters to the diagnosis of Mikhailov (fan-shaped units, size of pore diameter greater than 50 Ore). In the same publication they also described three new egg genera, including the type genus for the family Megaloolithidae. Altogether, they defined six egg species.
A g e / F o r m a t i o n - Upper part of the red clays in the Late Rognacian = latest Maastrichtian levels.
The type species, Megaloolithus mamillare (we replace here the oospecies name mammilare, not correct on the basis of the latine root, by mamillare) has short, fan-shaped shell units, and most of t h e m show parallel margins. The horizontal growth striations are convex from the base to the top, and are generally broken at the limits of the units. The shell thickness, without nodes and mamillae, ranges from 1,2 to 2,1 mm. The heights of the nodes varies from 0,3 to 1,2 mm and their average diameter is 1,0 ram. The pore diameters range from 75 to 150 lam. Well preserved eggshells from the uppermost Cretaceous levels in the Aix Basin, France (Les Br@gui~res locality) are closely related to M. mamillare, and have been tentatively referred to this species as aff. mamillare (Vianey-Liaud et al. 1994). The very close similarities of the Les Br@guigres type with some eggshells from Bagua Basin and from Central India allow us to establish a new species for the genus Megaloolithus, an egg species found on three continents in about the same horizons!
Megaloolithus VIANEY-LIAUDet al. 1994 Megaloolithus pseudomamillare nov. sp. VIANEY-LIAUD Figs. 1.1-3
Diagnosis As for Megaloolithus mamillare, however, differs in the following: frequently coa-
E t y m o l o g y - A closely related (pseudo) form ofM. mamillare. H o l o t y p e - LBR-3A, fragment and thin section (Fig. 1.2). T y p e - l o c a l i t y - Les Br@gui~res, Aix Basin, France.
M a t e r i a l a n d p r e s e r v a t i o n - Fragments from five disintegrated eggs (LBR 1, 2, 3, 4, 5).
Referred specimens India: Kheda Type A (Srivastava et al. 1986); Takli 1 and Pisdura tuberculate dinosaur eggshells (Vianey-Liaud et al. 1987); ? Titanosaurid Type III (Sahni et al. 1994). Peru: Laguna Umayo, large mamillae type; Bagua Basin, large mamillae type (Hirsch in Mourier et al., 1988).
Description - (See Vianey-Liaud et al. 1994: M. aff. mamillare, p. 158-162; figs. 11-7F-G-H, 11-9, 11-10). The new oospecies is close to M. mamillare with similar nodes size and pattern, similar pore canal diameters (65 lJm to 150 om); the nodes are generally coalescing, some being solitary. These two species differ only by a few characters. The eggshell is a little thinner (see Table 1), the fan-shaped units are not always well delimited from the base to the top, and the growth striations generally continue across adjacent units, becoming more and more convex from the base to the top. But some rare units are well delimited with growth striations equally arched from the base to the top. This morphology occurs also in Indian eggs described as (?) Titanosaurid Type III by Sahni et al. (1994), from Kheda, Takli and Kachch intertrappeans. D i s c u s s i o n - This oospecies cannot be classified in one of the morphotypes of Mikhailov. The t u b o s p h e r u l i t i c m o r p h o t y p e is defined by Mikhailov (1991) on the basis of some eggshells from France: "the shell layer is composed of shell units sharply separated from each other (a fanlike pattern can be traced up to the shell surface), have arched accretion lines and exhibit tuberculous elevations on the shell surface". This means that the shell units are tightly abutting, b u t not interlocking. Among the tuberculate French egg-
FIGURE 2 - Megaloolithus pseudornamillare nov. sp., Bagua Basin, Peru. 1. HEC 433-2, Morerilla locality, SEM, well preserved outer surface [x 23]. 2. HEC 381-1, E1 Pintor locality, LM, badly weathered outer surface [x 23]. 3. HEC 433-2, Morerilla locality, SEM, well preserved inner surface Ix 25]. 4. HEC 433-2, SEM, radial view, fresh fracture [x 50]. 1. Surface externe bien conserv~e. 2. Surface externe tr@s alt@rge. 3. Surface interne bien conservge. 4. Vue radiale, fra$chernent fracturge.
79
80
Locality and (number of m e a s u r e d fragments) Les Brggui~res (more t h a n 300) Takli 1 Pisdura Kheda Pongo de R e n t e m a E1 Pintor Fundo E1 Triunfo Morerilla
total range of thickness (ram)
(14) (4) (?) (2) (3) (12) (4)
1,03 to 1,99 0,69 to 1,19 0,81 to 0,91 1,0 to 1,5 0,97 0,76 to 0.86 0,60 to 1,17 1,09 to 1,44
m a i n r a n g e of thickness (ram)
1,21 to 1,57 0,80 to 1,15 0,81 to 0,91 0,97 0,76 to 0,86 1,00 to 1,17 1,09 to 1,44
Table 1
shells, this definition mainly concerns some oospecies within the oogenus Megaloolithus and especially M. siruguei and M. mamillare. The other oospecies were not known by Sochava (1971), E r b e n (1970), Zhao (1975,1979) or Mikhailov (1991). The tuberculate oospecies from Les Br6gui~res has the same pore-canal pattern than those ofM. siruguei and M. mamillare, but if some units are discrete and clearly fan-shape, a great p a r t of the units are interlocking. That arrangement is not completely the one defined as prolatospherulitic by Mikha~lov. "The prolatospherulitic morphotype is similar to the tubospherulitic morphotype, b u t the shell units are broader and losely arranged, less sharply separated from each other; the vertical borders and the fan-like pattern are well displayed only up to two/thirds to three/fourths of the eggshell thickness; above this portion, the wedges deviate laterally. Accretions lines are mainly horizontal". In M. pseudomamillare, there is no trace of lateral deviation of the wedges, and the accretion lines are not always horizontal, particularly under the nodes. The oospecies could represent a different type, of an intermediate stage between the tubospherulitic and the prolatospherulitic types.
DESCRIPTION AND DISCUSSION OF P E R U V I A N E G G S H E L L MATERIAL E G G S H E L L S FROM THE BAGUA BASIN (EL T R I U N F O FORMATION) Hirsch, in Mourier et al. 1988, divided the eggshell material from Bagua basin into the follo-
wing types: 1)"large mamillae"; 2) "vermiculate"; 3) "thick gekko-like"; 4) "avian-like", 0,64 mm; 5) "avian-like", 0,51-0,56 mm; 6) "thin gekko-like". This material can be described now more accurately and be assigned in most cases to specific morphotypes. However, the correlation of fossil eggshell to taxonomic taxa should be based on reliable evidence as identifiable embryonic remains within the eggs, or hatchlings associated with eggs.
Type 1: Dinosauroid spherulitic type, tubospherulitic morphotype, angusticanaliculate pore system The Hirsch's "large mamillae" type is here assigned to the above described new oospecies Megaloolithus pseudomamillare (Fig. 1, Table 1) Material and preservation - Twenty-one eggshell-fragm e n t s (HEC 380-1, 381-1, 382-1, 433) (Table 1). Preservation varies widely due to erosion. Ten radial t h i n sections and six specimens u n d e r SEM have been studied.
Description - The shell thickness varies from 0,81 to 1,44 mm, partly due to erosion and weathering. The sculpturing of the outer surface varies widely. The characteristic sculpturing shows single, often bulbous nodes of varying size and heights, often coalescing to ridges and groups composed of two or more nodes. Between the nodes are deep valleys of irregular size and shape (Fig. 1). In the thinner eggshell (Fig. 2.2), erosion reduced the ridges to sharp-topped, narrow, ridges, thus levelling off and widening the valleys resulting in a sculpture of retiform appearance. The inner surface (Fig. 2.3) shows protruding large, but narrow, mamillary knobs with deep and wide interstices between them. The mamillae are irregu-
FIGURE 3 - Megaloolithus p s e u d o m a m i l l a r e nov. sp., Bagua Basin, Peru. 1. HEC 382-1A, Fundo E1 Triunfo locality, PLM, radial view [x 35]. 2. as 1 [x 145]. 3. HEC 382-1B, Fundo E1Triunfo locality, PLM, radial view [x 50]. 4. as 3, PLM polarized, radial view [x 50]. 5. HEC 433-4, Morerilla locality, PLM radial view Ix 35]. 6. as 5, PLM polarized, radial view [x 50]. 7. as 5, PLM, radial view, x 50.1. L a m e mince en lumi~re polarisde. 3. L a m e mince en lumi~re polarisde. 4. L a m e mince en lumi~re polarisde, rue radiale. 5. L a m e mince en lumi~re polarisde, vue radiale. 6. L a m e mince en lumi~re polarisde, vue radiale. 7. L a m e mince en lumi~re polarisde, vue radiale.
81
2
82 larly distributed, mostly occurring singly, but also forming groups or rows of two or more mamillae. Radial views show that the shell layer is composed of shell units widely varying in size and shape and in their relationships to the adjacent units (Fig. 2.4, Fig. 3.7). Although the image of some shell units is discrete, all shell units are fused with a more or less large area of their borderlines to their neighbours. The continuous shell layer is in m a n y places relatively thin (about one third of shell thickness), alloting one third to the layer of widely spaced mamillae and one third to the sculpture of the outer surface. The horizontal growth lines of the continuous shell layer following the contour of the shell are proof of fusion. These growthlines arch more strongly above the mamillae and within the node areas. The shell units are composed of fine radiating crystallites extending in a fan-like pattern from the nucleation center to the outside of the shell (Fig. 2.4, Fig. 3.2). The extinction pattern is sweeping. The observed narrow pore canals are mostly straight, only sometimes slightly curved or at an angle (Fig. 3.7). The pore openings, located in the valleys, are subcircular to elliptical and of varying size (Fig. 2.1). Sometimes the openings are funnellike, especially between high bulbous nodes overhanging the opening.
Discussion
The eggshell f r a g m e n t s from Bagua, Northern Peru, and Central India show very close similarities in their microstructures and in their surface ornamentations with the French eggshells from Les Br~gui~res. This is the reason why, despite that they are a little thinner, they have been referred to the same oospecies
Mega!oolithus pseudomamillare. In the Aix Basin, until now, M. pseudomamillare has b e e n found only in the last Late Maastrichtian levels. The stratigraphical informations for the Indian fragments are in agreement with that. All the Bagua eggshell specimens were collected in the basal Redbeds of Fundo E1 Triunfo Formation, ranging from Late Campanian to Maastrichtian on paleontological evidence (Mourier et al. 1988).
Type 2: D i n o s a u r o i d spherulitic (formerly vermiculate) Morphotype not clearly distinguishable; it m a y represent a new type or a variant to be placed between the tubospherulitic and prolatospherulitic morphotype (Fig. 3.3-7, Fig. 4).
Material and preservation - Two weathered eggshell fragments (HEC 434) from the Morerilla locality. Examined in three thin sections and two shell fragments u n d e r the SEM.
Description - The shell thickness is 1,09 to 1,14 mm (Table 2). The outer surface is sculptured with vermicular ridges (Fig. 4.1). The deep irregular depressions between the ridges penetrate the shell to different depths, some of them becoming irregular shaped pore canals (Fig. 4.1,4). The inner surface is smooth and mamillae cratered, with large, irregularly spaced interstices. In radial view, large irregular voids and enlarged pore canals filled with sparite, can be observed indicating strong erosion. The remaining eggshell material shows a shell layer with interlocking and single units. The growth lines are horizontal, but strongly arched in single units. The shell units are composed of radiating fine crystals, and show a sweeping extinction pattern (Fig. 3.3-7, Fig. 4.1-3, 5).
Discussion - One of the authors (K.H.) examined structural almost identical eggshell with a shell thickness varying from 1,4-1,8mm from the Lower Cretaceous Cloverly Formation in Montana, USA. The different stages of erosion of the structure of these eggshells also suggested that they may represent a new morphotype, like a variant between tuboand prolatospherulitic. However, the scarcity of the material did not allow to define a new morphotype. T y p e 3: Ornithoid Type, Ratite m o r p h o t y p e
(formerly "Thick gecko-like'), angusticanaliculate pore system (Fig. 5.1,2) Material - Two eggshell fragments (HEC 435) of different shell thickness from the Morerilla locality. Studied in two radial thin sections and two observations under the SEM.
Description - Shell thickness is 0,82 mm to 1,14 mm. Angusticanaliculate pore canals. The outer surface is sculptured with low granular nodes, irregularly spaced on a smooth surface (Fig. 5.1). The inner surface is eroded with no distinct mamillae visible. The thicker fragment shows several dimples each with a pore opening in center. In radial view, two distinct shell layers are visible, with an abrupt change of structure between them (Fig. 5.2). The mamillary layer exhibits a distinct structure, whereas the continuous layer shows only a pronounced horizontal layering. The columnar herring bone pattern visible under SEM is due to recrystallization. The extinction p a t t e r n is irregular.
FIGURE 4 - Dinosauroid spherulitic type, ?new morphotypes, Bagua Basin, Peru. 1. HEC 434-2, Morerilla locality, PLM, radial view [x 35]. 2. as 1 [x 145]. 2.3. as 1 [x 145]. 4. as 1, SEM, outer surface [x 27]. 5. HEC 434-1, Morerilla locality, SEM, radial view [x 31]. 1. L a m e m i n c e en lumi~re polarisge, vue radiale. 2. C o m m e 1.3. C o m m e 1.4. C o m m e 1, surface externe 5. Vue radiale.
83
0
Q
3
4
84
Localities and types Morerilla Morerilla Fundo E1 Triunfo Fundo E1 Triunfo Pongo de R e n t e m a
fragment numbers type type type type type
2 3 4 5 6
2 2 1 2 2
eggshell thickness (ram) 1,09 0,82 0,64 0,51 0,12
and 1,19 and 1 , 1 4 (O,5O) and 0,61 and 0,15
Table 2
The difference in thickness and the absence of dimples in the t h i n n e r eggshell suggest t h a t the two f r a g m e n t s are from different parts of the egg, or w e r e s u b m i t t e d to different weathering. Dimples w i t h pore holes have been observed on t h e i n n e r shell surface of modern gecko and some gecko-like fossil eggshell. However, the distinct s t r u c t u r e with its a b r u p t s t r u c t u r a l change b e t w e e n the two layers puts these two eggshells in the R a t i t e m o r p h o t y p e (Mikha~lov 1991).
The outer surface is smooth, and the pore openings are located in small depressions. The inner surface shows very fine crystals suggesting mamillae. The radial section shows two distinct layers with abrupt change of structure between them (Fig. 5.5,6). The mamillary layer occupies about one fourth of the eggshell thickness. The continuous layer shows a faint horizontal layering and irregular divergent lines. The extinction p a t t e r n in the continuous layer shows irregular divergent columnar forms.
T y p e 4: Ornithoid type, Ratite morphotype
Discussion - These two calcitic fragments can
(formerly avian-like, 0,64 ram) (Fig. 5.1-4)
belong to the ratite morphotype on the basis on their distinct mamillary layer and the abrupt change in structure toward the continuous layer. The divergent lines could be due to recrystallization of the shell. However, the divergent lines and especially the columnar images in the extinction pattern point to the angustispherulitic morphotype of the dinosauroid type In eggshell of ratite morphotype, identifiable embryonic remains of theropod dinosaurs have been found, suggesting a correlation to this taxonomic group. However, the ratite morphotype is also represented in avian eggshells. These eggshell fragments are similar, b u t thinner, to that described from Laguna Umayo (0,75 mm) by Kerourio & Sig~ (1984).
M a t e r i a l - One shell f r a g m e n t (HEC382-3) from the Fundo E1 Triunfo locality. Studied in one radial t h i n section.
Description - Eggshell thickness 0,64 mm (including nodes), 0,50 mm between the nodes. Outer surface sculptured with nodes of 0,5 mm diameter. The spaces between the nodes vary from 1,5 mm to 2,0 mm. No pore openings are visible. The inner surface displays very fine cratered mamillae. In radial view, a distinct mamillary layer, occupying one fifth of t h e shell thickness, with an abrupt change in structure at the boundary to the continuous layer are visible (Fig. 5.4). The inner half of the continuous layer shows a pronounced horizontal layering, whereas; in the outer half, especially in the nodes, a fine radiating structure can be detected (Fig. 5.4). The extinction pattern is irregular.
Type 5: Ornithoid type, Ratite morphotype or Dinosauroid type, Angustispherulitic morphotype (formerly avian-like, 0,51-0,61 mm) (Fig. 5.5,6) M a t e r i a l - Two eggshell fragments (HEC382-4) from the Fundo E1 Triunfo locality. Examined in three radial thin sections.
Description - The shell thickness is 0,51 mm and 0,61 ram.
Type 6: ? Geekonoid type (formerly "thin gecko-like") (Fig. 6.1,2) M a t e r i a l - Two small shell fragments (HEC380-6, 380-7) from the Pongo de R e n t e m a locality. Studied in three t h i n sections and two observations u n d e r the SEM.
Description - The shell thickness is 0,12 mm and 0,15 mm. The outer surface is smooth, partially covered with secondary deposit. The radial view of one specimen shows some vertical structure, however no extinction p a t t e r n (Fig. 6.1). The other specimen (Fig. 6.2) displays a faint vertical columnar structure and a columnar
FIGURE 5 - Ornithoid-ratite type, ratite morphotypes, Bagua Basin, Peru. 1. HEC 435-2, Morerilla locality, PLM, radial view [x 50]. 2. as 1, SEM, fresh fracture, radial view [x 32]. 3. HEC 382-3, Fundo E1 Triunfo locality, PLM polarized, radial view [x 50]. 4. as Fig. 26, PLM, radial view [x 145]. 5. HEC 382-4, Fundo E1Triunfo locality, PLM, radial view [x 50]. 6. as 5 [x 145]. 1. L a m e mince en lumi~re polarisde, vue radiale. 2. Fracture fra~che, vue radiale. 3. L a m e mince en lumi~re polarisde, vue radiale. 4. C o m m e 3, vue radiale. 5. L a m e mince en lumi~re polarisde, vue radiale. 6. Comme 5.
85
5
6
86 extinction pattern. No distinct structure is visible under the SEM.
A d d i t i o n a l t h i n e g g s h e l l m a t e r i a l from the Umayo Formation
D i s c u s s i o n - Both shells are candidates for the
M a t e r i a l - Thirteen thin fragments (0,20 to 0,30 m m thick) (HEC 385, 386) from two localities and different levels in the Umayo Fm. (LU3 and Chulpas) (Fig. 6.3,4). They have been studied in four thin sections and two fragments have been examinated u n d e r the SEM.
geckonoid morphotype. However, no distinct assig n m e n t is possible. EGGSHELLS FROM LAGUNA UMAYO (UMAYO FORMATION) K e r o u r i o a n d Sig~ (1984) described two t y p e s of eggshells f r o m t h i s area. R e g r e t t a b l y a loss of m a t e r i a l in Kerourio's care occurred; at l e a s t it h a s n o t b e e n possible to locate a n i m p o r t a n t p a r t of t h e original a n d a d d i t i o n a l m a t e r i a l .
Kerourio & Sign's TYPE 1: D i n o s a u r o i d spherulitic type,Tubospherulitic morphotype, t u b o c a n a l i c u l a t e pore s y s t e m M a t e r i a l - The eggshell of this type was represented by less t h a n 10% of the specimens of this locality. Shell thickness 0,80
D i s c u s s i o n - The fragments analyzed with the microprobe showed t h a t t h e y are composed of calcium carbonate. Thus, most of t h e m are probably eggshell; however, the scarcity of the material, recrystallization and some alteration of the structure do not allow assignments to a specific morphotype.
BIOSTRATIGRAPHICAL PAI,AEOGEOGRAPHICAL IMPLICATIONS
AND
mm.
D i s c u s s i o n - The structure of this type was described as tubocanaliculate. Thus it can without doubt be assigned to the genus Megaloolithus of the family Megaloolithidae. An assignment to a known specific species or the establishment of a new species is impossible w i t h o u t additional material.
K e r o u r i o & Sign's T y p e 2: O r n i t h o i d t y p e , R a t i t e m o r p h o t y p e or D i n o s a u r o i d s p h e rulitic type, angustispherulitic morphotype M a t e r i a l - Shell fragments of this type were most commonly found at this locality. Shell thickness 0,70 mm.
D i s c u s s i o n - The description of the structure of this type is not clear enough to assign it to a specific morphotype and no pore canals were observed. The authors t a l k about two shell layers, the m a m i l l a r y a n d the spongy or continuous layer. However, t h e y do not m e n t i o n an abrupt change of s t r u c t u r e between these two layers. They also describe t h a t the crystalline structure in the spongy layer ceases to be grouped in distinct units, but t h a t t h e y curve inwards w i t h o u t deftnite orientation. Thus we could be confronted by two completely different morphotypes, the ratite morphotype and the angustispherulitic morphotype. Only additiohal s t u d y material or examination of the thin sections and SEM specimens would allow us to solve this problem.
The Bagua eggshells collected in different outcrops (so-called Fundo E1 Triunfo, Morerilla, E1 Pintor, Pongo de Rentema, etc.) of the same undoubted Late Cretaceous formation do not bear problem in the geological significance of their reported histological structures. Their description has reference value in correlational studies. This material is also of paleobiogeographic interest since it contributes to reveal a large gondwanian and laurasian dispersal of a given eggshell type at the end of the Cretaceous, with possible inference for intercontinental time-correlation. Nevertheless, as the typologic studies of eggshells are just beginning, and the systematic significance of the structures similarities remaining questionable, it is difficult to go farther in the palaeobiogeographical interpretations. Regarding the L a g u n a Umayo shells, the partial loss of the reference material and the political situation in Peru prevented to obtain complement a r y data for several years. However, the interpretation of these eggshells has a critical bearing in the discussion of the Late Cretaceous vs Early Tertiary age of the fossil-bearing level, a n d of course t h a t of its whole contents. One of the two described eggshell types is dinosaurian, the other one is ratite-avian or dinosaurian with a ratitemorphotype. This assesment confirms the previous one (Kerourio & Sig6 1984) as regards the identification of at least one dinosaur-type eggshell. In contrast, in recent m a m m a l i a n literature
FIGURE 6 - 1-2. Gecko-like type, Pongo de R e n t e m a locality, Bagua Basin, Peru. 1, HEC 380-6, PLM, radial view [x 145]. 2. HEC 380-7, PLM, radial view [x 145]. 3-4. U n d e t e r m i n e d type, Laguna Umayo, Peru. 3, HEC 385-1, LU3 locality, PLM, radial view [x 145]. 4, HEC 386-1, Chulpas locality, PLM, radial view [x 145]. 1. L a m e m i n c e en lumi~re polarisde, vue radiale. 2. L a m e m i n c e en lumi~re polaris~e, ru e radiale. 3-4. Type indgtermin~. 3, l a m e m i n c e en lumi~re polarisge, vue radiale. 4. L a m e m i n c e en lumi~re polaris~e, vue radiale.
87
2
3
88 the Laguna U m a y o locality is generally considered as Early Tertiary (Paleocene) in age. The arguments are not given, but a progressive stage of the m a m m a l fauna is implicitly favoured, following Van Valen 1988. Nevertheless only this author tried to take into account the whole reported facts. According to him, the Laguna Umayo dinosaurs are, among some alleged occurrences in different areas of the World, the evidence of the survival of these reptiles within the earliest million years in the Tertiary (Sloan et al. 1986; Van Valen 1988). This assumption implies in parallel, that some charophyte species, known to be restricted to the Late Cretaceous, persisted in the Tertiary. However, a recent revision of Andean charophyte data generally does not support this view (Feist & Grambast-Fessard in Jaillard et al. 1993 : 646; Jaillard et al. 1994). But the species Feistiella gildemeisteri, one of the Laguna Umayo species, is now recorded from the Santa Lucia Fro. (within Tiupampa section), showing the extension of the species up to the Late Paleocene (Sempere et al., in print). Other arguments, not published but confidentially reported by authors who do not know the locality are: 1- Charophyte, eggshell, and mammal remains from Laguna Umayo do not have the same stratigraphic origin. However it is a fact that the LU 3 level, mainly excavated, consists of a 30 to 40 cm thick microconglomeratic bed, containing all these different fossils which were obtained together from the extracted blocks (Sig6 1972); 2- Charophyte and eggshell remains would represent Cretaceous fossils reworked in a younger formation. However the thinness and brittlehess of these fossils are at least as important as those of the m a m m a l teeth considered to be not reworked in this assumption. Furthermore the fossiliferous sediment corresponds to thin channel-deposits, as recurrent facies in a clay dominant formation. In these channels various tiny d e s e g r e g a t e d aquatic and t e r r e s t r i a l organic remains were low-energetically transported and deposited in lacustrine warm waters with abundant carbonate pellet precipitation. Such conditions in sedimentation do not agree with the hypothesis of an intensive erosion of underlying formations. In the absence of other significant data, the kind of L a g u n a U m a y o eggshells, as well as the stratigraphic and geographic range of the animals to which they correspond, are very important in this discussion. First the dinosaur eggshell-type is confirmed. Second the ornithoid-ratite / or angustispherulitic dinosauroid type is found in both Laguna Umayo and Fundo E1 Triunfo (Bagua basin) deposits. Both also share the charophyte Amblyochara peruviana. These data finally could
support the tentative correlation of the Umayo Formation a n d the Fundo E1 Triunfo Formation., the latter well dated as Late Cretaceous, probably Maastrichtian on the basis of intercontinental eggshell correlation and the occurrence of the World-wide Maastrichtian Schizorhiza stromeri sclerorhynchid selachian within the underlying upper Celendin Formation (Mourier et al. 1988; Cappetta in Jaillard et al. 1993).
CONCLUSION The first conclusion is that there is no doubt on the dinosaurian nature of some eggshells from both the B a g u a Basin and t h e Vilquechico Formation, Southern Peru. The second result is that the oofamily Megaloolithidae, recorded in Western Europe and in India, is also present in the two studied South American Andean basins. Moreover, it seems that the same oospecies exists in Southern France, Central India and in the Bagua Basin. Though detailed and precise typologic studies of the eggshells and their stratigraphical applications are j u s t beginning, we can deduce some stratigraphical indications on the basis of this common occurrence. The oospecies (Megaloolithus pseudomamillare nov. oosp.) is recorded in S o u t h e r n France only in the last Late Maastrichtian deposits, and not before, and probably this is the same case for the Central Indian localities. In this preliminary state of knowledge, the Bagua localities could be Late Maastrichtian in age. This presumption is consistent with the available biostratigraphic information. Acknowledgements
- M a n y t h a n k s to L a u r e n c e Meslin, w h o h a s d r a w n the figures 3 to 6. Publication U M R 5554 n ° 97-014.
REFERENCES AUDEBAUD E., LAUBACHER G. & MAROCCO R. 1976 - Coupe g6ologique des Andes du Sud du P6rou de l'Oc6an Pacifique au bouclier br6silien. Geologische Rundschau, 65: 223-264. CLEMENS W.A., LILLEGRAVEN J.A., LINDSAY E.H. & SIMPSON G.G. 1979 - Where, when and what -- A survey of
known Mesozoic mammal distribution. In LILLEGRAVENJ.A., KIELAN-JAWOROWSKAZ. & CLEMENS W. A. (eds.), Mesozoic mammals: the first two-thirds of mammalian history, 7-58. University of California Press, Berkeley. DAUPHINY. 1990 - Incidence de l'6tat diag6n6tique des coquilles d'oeufs de dinosaures sur la reconnaissance des morphotypes - exemple du Bassin d'Aix en Provence. Comptes Rendus de l'Acaddmie des Sciences, Paris, 310, 2: 849-854.
89 DUGHI R. & SIRUGUE F. 1958 - S u r les oeufs de dinos a u r e s du b a s s i n fluvio-lacustre de Basse-Provence.
83rd Congr~s des Soci~t~s Savantes, Section des Sciences: 183-205. ERBEN H.K. 1_970 - U l t r a s t r u k t u r e n u n d M i n e r a l i s a t i o n r e z e n t e r u n d fossiler E i s c h a l e n bei Voegeln u n d Reptilien. Biomineralisation, 1, 66 p. HmSCH K. 1994 - U p p e r J u r a s s i c e g g s h e l l s from t h e W e s t e r n i[nterior of N o r t h A m e r i c a . In CARPENTER K., HIRSC1~IK. & HORNER J.R. (ed.), Dinosaur Eggs and Babies. C a m b r i d g e U n i v e r s i t y P r e s s : 138-150. HmSCH K. & QUINN B. 1990 - Eggs a n d eggshell fragm e n t s from t h e u p p e r Cretaceous Two Medicine form a t i o n of M o n t a n a . Journal of Vertebrate Paleontology, 10: 491-511. GRAMBAST L., MARTINEZ M., MATTAUER M. & THALER L. 1967 - Perutherium altiplanense nov. gen., nov. sp., p r e m i e r n m m m i f e r e m6sozo~que d'Am6rique du Sud. Comptes Rendus de l'Acad~mie des Sciences, Paris, (D) 264: 707-710. JAILLARD E., CAPPETTA H., ELLENBERGER P., FEIST M., GRAMBAST-FEsSARD N., LEFRANC J.P. & SIGE B. 1993 Sedimentol0gy, palaeontology, biostratigraphy and correlation of the Late Cretaceous Vilquechico Group of southern Peru. Cretaceous Research, 14 (6): 623661. JAILLARD E., FEIST M., GRAMBAST-FESSARD N. & CARLOTTO V. 1994 - Senonian - Paleocene charophyte succession of t h e P e r u v i a n Andes. Cretaceous Research, 15: 445-456. KEROURIO P. & SInE B. 1984 - U a p p o r t des coquilles d'ceufs de d i n o s a u r e s de L a g u n a U m a y o fi l'fige de la F o r m a t i o n Vilquechico et /~ la compr6hension de
Perutherium altiplanense. Newsletters on Stratigraphy, 13: 133-142. MII~tAILOV K.EI 1991 - Classification of fossil eggshells of a m n i o t i c v e r t e b r a t e s . Acta Palaeontologica Po!onica, 36: 193-238. MIKHAILOV K.E., SABATHK. & KURZANOVS. 1994 - Eggs a n d n e s t s from t h e Cretaceous of Mongolia. In CARPENTER K., HmscH K. & HORNER J.R. (eds), Dinosaur Eggs and Babies. C a m b r i d g e U n i v e r s i t y Press: 138-150 MOURIER T., JAILLARD E., LAUBACHER G., NOBLET C., PARDO A, SIGI~ B. & TAQUET P. 1986 - D~couverte de restes dinosauriens et mammalien d'fige crgtac6 sup6rieur la base des couches rouges du synclinal de Bagua, Andes nord-pdruviennes: aspects stratigraphiques, sgdimentologiques et pal6og~ographiques concernant la r6gression fini-crgtac~e. Bulletin de la Socidtd g~ologique de France, (8) 2 (1): 171-175. MOURIER T., BENGTSON P., BONHOMME M., BUGE E., CAPPETTA H., CROCHET J.-Y., FEIST M., HmSCH K.F., JAILLARD E., LEFRANC J.P., MOULLADE M., NOBLET C., PONS D., I[~EY J., SIGI~ B., TAMBAREAU Y. & TAQUET P. 1988 - The Upper Cretaceous - Lower Tertiary marine to continental transition in the Bagua basin, Northern Peru. Paleontology, biostratigraphy, radiometry, correlations. Newsletters on Stratigraphy, 19: 143-177. NAESER C.W., CROCHET J.-Y., JAILLARD E., LAUBACHER G., MOURIER T. & SIGE B. 1991 - Tertiary Fission-track
ages from t h e B a g u a syncline ( N o r t h e r n Peru).
Journal of South American Earth Sciences, 4: 61-71. NEWELL N.D. 1949 - Geology of t h e Titicaca region, Peru and Bolivia. Geological Society of America, Memoirs, 36:111 p. PENNER M.M. 1985 - The p r o b l e m of d i n o s a u r extinction. contribution of the s t u d y of t e r m i n a l Cretaceous eggshells from s o u t h e a s t France. Geobios, 18:665-669 PORTUGAL J.A. 1974 - Mesozoic a n d Cenozoic S t r a t i g r a p h y a n d Tectonic E v e n t s of Puno - S a n t a Lucia area, D e p a r t m e n t of Puno, Peru. The American Association of Petroleum Geologists Bulletin, 58 (6): 982-999. SAHNI A., TANDON S.I~., JOLLY A., BAJPAI S., SOOD A. & S. SRINIVASAN 1994 - Upper Cretaceous dinosaur eggs and nesting sites from the Deccan volcanosedimentary province of peninsular India. In CARPENTER K., HIRSCH K. & HORNER J.R. (eds), Dinosaur Eggs and Babies. C a m b r i d g e U n i v e r s i t y P r e s s : 204-226. SEMPERE T., BUTLER R.F., RICHAI~DS D.R., MARSHALL L.G., SHARP W. & SWISHER C.C. (in press) - Stratigraphy and chronology of Upper Cretaceous-lower Paleogene strata in Bolivia and northwest Argentina. Geological Society of America, in print. SIGE B. 1968 - Dents de m i c r o m a m m i f e r e s et f r a g m e n t s de coquilles d'~eufs de d i n o s a u r i e n s d a n s l a faune de v e r t e b r a s du Cr~tac6 s u p ~ r i e u r de L a g u n a U m a y o (Andes p~ruviennes). Comptes Rendus de l'Acadgmie des Sciences, Paris, (D) 267: 1495-1498. SInE B. 1972 - L a faunule de m a m m i F e r e s du Cr6tac6 s u p 6 r i e u r de L a g u n a U m a y o (Andes p6ruviennes).
Bulletin du Musgum National d'Histoire Naturelle, (3) 99: 375-405. SLOAN R.E., RIGBY J.K., VAN VALEN L.M. & GABRIEL D. 1986 - Dinosaur extinction and simultaneous ungulate radiation in the Hell Creek Formation. Science, 232: 629-633. SOCHAVA A.V. 1971 - Two types of eggshells in Senonian Dinosaurs. Paleontological Journal, 5: 353-361. SRIVASTAVA S., MOHABEY M.B., SAHNI A. & PANT S.C. 1986 Upper Cretaceous dinosaur egg clutches from Kheda District, Gujarat, India: their distribution, shell ultrastructure and paleoecology. Palaeontographica, Abt. A 193: 219-233. VIANEY-LIAuD M., gAIN S.L. & SAHNI A. 1987 - D i n o s a u r eggshells from t h e L a t e Cretaceous I n t e r t r a p p e a n and L a m e t a formations (Deccan, India). Journal of Vertebrate Paleontology, 7: 408-424. VIANEY-LIAUD M., MALLAN P., BUSCAIL O. & MONGELARD C. 1994 - Review of French dinosaur eggshells: morphology, structure, mineral, and organic composition. In CARPENTER K., HIRSCH K. • HORNER J.R. (eds), Dinosaur Eggs and Babies. C a m b r i d g e U n i v e r s i t y Press: 151-183. VAN VALEN L.M. 1988 - P a l e o c e n e d i n o s a u r s or Cretaceous u n g u l a t e s in S o u t h A m e r i c a . Evolutionary Monographs, 10, 79 p. WILLIAMS D.L.G., SEYMOUR R.S. & KI~ROURIO P. 1984 Structure of fossil dinosaur eggshell from the Aix basin, France. Palaeogeography, Palaeoclimatology, Palaeoecology, 45: 23-37.
90 Z ~ o Z. 1975 - The microstructure of the d i n o s a u r eggshells of N a n s h i u n g , K w a n t u n g . Vertebrata PalAsiatica, 13: 105-117. ZHAO Z. 1979 - The a d v a n c e m e n t of researches on the d i n o s a u r i a n eggs i n China. In South China Mesozoic and Cenozoic "Red Formation" (Beijing: Science P u b l i s h i n g Co.): 329-340.
Campus Box 218 Boulder, Colorado 80309, USA A. S A H N I
Center of Advanced Studies in Geology Panjab University Chandigarh 160014, India
B. SIG~ M. VIANEY-LIAUD Institut des Sciences de l'Evolution, UMR 5554 Universit6 Montpellier II Place Eugene Bataillon F-34095, Montpellier Cedex 05 t K. H I R S C H
University of Colorado Museum
Institut des Sciences de l'Evolution, UMR 5554 Universit~ Montpellier II Place Eugene Bataillon F-34095, Montpellier Cedex 05 present adress: Universit~ Claude-Bernard, Lyon ] Centre des Sciences de la Terre 43, bd du 11 Novembre F-69622 Villeurbanne cedex
