AsociaciónPaleontológicaArgentina.PublicaciónEspecial7 VIIInternationalSymposiumon MesozoicTerrestrialEcosystems:145-149.BuenosAires,30-6-2001 A b e lis a u r id pedal u n g u a ls fr o m th e L a te C r e ta c e o u s ISSN0328-347XZYXWVUTSRQP o f I n d ia Fernando E. NOVAS! and Saswati BANDYOPADHYAY2 Abstraet. The ungual phalanges of theropod dinosaurs discovered in the Lameta Formation (Maastrichtian),centralIndia,exhibitdistinctivecharactersunknown in other theropods.Hence,their taxonomic identification remained obscure since their original description in 1933.Recent discoveries of abelisaurid theropods in Patagoniaindicate that the phalangesfrom India belong to the foot of the~e~inosaurs. New information on the foot skeletonof this group of CretaceousGondwanan predators lS mcluded herein. Key words. Theropoda. Abelisauridae. Unguals. Cretaceous. Gondwana. Xenotarsosaurus; Bonaparte and Novas, 1985; Martínez et al., 1986; Bonaparte et al., 1990), India The Late Cretaceous (Maastrichtian) Lameta ilndosuchus; Chatterjee and Rudra, 1996), and Formation of central India has yielded dissociated el- Madagascar (M ajungatholus; Sampson et al., 1998). ements of a variety of predatory dinosaurs. The maThis considerable amount of information about terials were described by Frederich von Huene (in abelisaurid anatomy has served as a valuable guide Huene and Matley, 1933), who recognized nine to resolve confusing taxonomic aspects of the Indian theropod species from a fossil quarry at Bara Simla theropods. lndosuchus Hill (Madhya Pradesh, India). They are:onmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Currently, lndosuchus, lndosaurus, and also rapiorius Huene, Indosaurus matleyi Huene, CompsoLaeoisuchue, are interpreted as members of suchus solus Huene, Laeoisuchus indicus Huene, Abelisauridae (Bonaparte and Novas, 1985; Molnar, [ubbulpuria tenuis Huene, Coeluroides largus Huene, 1990; Chatterjee and Rudra, 1996; Sampson et al., Dryptosauroides grandis Huene, Ornithomimoides mo1998; Novas and Bandyopadhyay, 1999). Moreover, bilis Huene, and Ornithomimoides (?) barasimlensis the con troversial taxa "Compsosuchus", "DryptoHuene. Huene also described a considerable amount sauroides", "Ornithomimoides", and "[ubbulpuria" are of theropod hindlimb bones (e.g., femora, tibiae, represented by vertebrae corresponding to different metatarsals, and pedal phalanges) that he could not regions of the neck and tail that also exhibit abelirefer to any of these species. On the contrary, such saurid features (Novas and Bandyopadhyay, 1999). bones were vaguely interpreted by him as correNow, abelisaurid material from the Upper sponding t o "allosaurid" o r "coelurosaurid" theroCretaceous rocks from NW Patagonia settles the long pods (Huene and Matley, 1933). standing confusion about the theropod unguals from Phylogenetic relationships of the Indian India, and establishes its abelisaurid affinity. theropods has been unknown since then, and virtually no progre ss has been attained about the systemA b b r e v ia tio n s atic allocation of the abundant post-cranial remains (e.g., Romer, 1956; Walker, 1964; Chatterjee, 1978; AMNH, American Museum of Natural History, Molnar, 1990;Norman, 1990).Fortunately, the last 15 New York; GSI, Geological Survey of India, Calcutta; years has been highly prolific in discoveries of MCA, Museo "Carlos Ameghino", Cipolletti; SUNY, abelisaurid theropods in Upper Cretaceous beds State University of New York, Stony Brook; YPM, from Patagonia (e.g., Abelisaurus, Carnoiaurus, Yale Peabody Museum, New Haven. I n tr o d u c tio n 'CONICET. Laboratory Argentino de Ciencias of Comparative Anatomy, Museo Naturales, Av. Angel Gallardo 470, C:14050JR a\.lenQ~Aires, Argentiml, E-mail: fernovas@yahou.com.ar. 'Geological Studies Unit, Indian Statistical Institute, Barraekpore Trunk Road, Calcutta 700 035, India. Email saswati@isical.ac.in. ©AsociaciónPaleontológicaArgentina M o r p h o lo g y o f a b e lis a u r id from Patagonia 203 p e d a l u n g u a ls a n d I n d ia The new abelisaurid specimen (MCA 56) includes two pedal unguals (figure 1) apparently from digit 0328-347X/01$00.00+50 146XWVUTSRQPONMLKJIHGFEDCBAF.E. Navas and S. Bandyopadhyay A E zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA B e o ZYXWVUTSRQPO A-E, digit IV ungual, presumably of the left foot, of an indeterminate abelisaurid (MCA 56) from the 'Río Limay Formation, northwestern Patagonia, in A, medial, B, lateral, C, dorsal, D, ventral, and E, proximal views. Scale bar: 2 cm. F ig u r e 1 . A.P.A. Publicación Especial 7, 2001 Abelisa urid pedal unguals from India 147 IV of the left and right feet. The unguals were found ,theropods, the ventral surface of the ungual is in association with other hindlimb elements and der- smooth and transversely convex (e.g., Allosaurus, mal skull bones that show a characteristic pattern of Sinraptor; Madsen, 1976; Currie and Zhao, 1993) or (e.g., anastomosed grooves delimiting flat (e.g., Deinonychus YPM 5205). Interestingly, ornamentationonmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA a mosaic pattern of raised areas) found in other Noasaurus, the purported sister group of Abelisauridae (Novas, 1992, 1997) also has a ventrally exabelisaurids (e.g., Carnotaurus, Abelisaurus, M ajungatholus); distal caudal vertebrae were also collected, cavated ungual, although it is located in a more proxthe morphology of which fits well with that of imal position (Bonaparte and Powell, 1980). Pedal unguals of indeterminate theropods from M ajungatholus (specimen 93161-14 at SUNY) and the Lameta Formation (Huene and Matley, 1933) lndosuchus (AMNH 1957, 1958). The unguals, nearly 6.5 cm when complete, are were sorted into two subsets: "allosaurid" manual blunt and asymrnetrical. They are arched (presum- (specimen K27/ 633) and pedal unguals (specimens ably medially), with the lateral surface strongly con- K27/524, K27/537, K27/543, K27/551, K27/634, vex and the internal surface almost flat. As a result of K27/635, K27/636, and K20/399), and "coelurothis asymmetry, the medial surface of the ungual is saurid" pedal unguals (e.g., K27/625, K27/629, also exposed dorsally. Both lateral and medial sur- K27/630, K27/631, and K27/632). We were able to and faces have wide canals that show a distinct, proxi- access only K27/634, K27/632, K27/633, mally bifurcated, "Y"-shaped pattem. The bifurca- K27/524, which are amenable for comparison with tion is at mid-length. The grooves are deeper on the the Patagonian unguals. lateral rather on the medial side of ungual. The "Y"Ungual phalanx K27/634 (figures 2.A-D) is transshaped groove of the lateral surface bounds a con- versely wide and almost symmetrical, and may be spicuous, triangular bump. There is no proximoven- from the central toe (digit I1I).As in abelisaurid untral flexor tubercle. The ventral surface of the ungual, guals from Patagonia, it has deep furrows on both instead, is proximally flat, but has a narrow and deep sides that bifurcate at mid-length and bounding a groove centrally. The proximal articular contour is prominent bump. Also, the ventral surface is furtriangular, and the proximodorsal lip is prominent rowed. Ungual phalanx K27/524 (figures 2.E-F; the same collection number was originally used as well and tongue-shaped. These unguals exhibit the following peculiar fea- for a non-ungual phalanx), was interpreted as betures distinguishing them from other theropods (e.g., longing to a "coelurosaurid" by Huene, but may belong to pedal digit IV because it resembles the ungual Allosaurus, Sinrapior, Tyrannosauridae, Ornithomimidae, Troodontidae, Dromaeosauridae, Alvarez- of this digit of Sinrapior (Currie and Zhao, 1993). Ungual phalanx K27/632 (Huene and Matley, sauridae): 1) Grooves bifurcated proximal1y (figure LB). 1933) has the same characters as in K27/634. Most tetanurines (e.g., Allosaurus AMNH 680, 5750; However, because ungual K27/ 632 is more compressed transversely and asymmetrical than the othSinraptor; Currie and Zhao, 1993; Alectrosaurus AMNH 6554) have a simple groove along both later- er unguals described by Huene, it may correspond to al and medial surfaces. Although some coelurosauri- digit 1. It is the smallest of all the available unguals. an theropods have "Y"-shaped grooves (e.g., Also, it has a strongly keeled dorsal margin, in agreePatagonykus; Novas, 1997; Troodon AMNH 2137), the ment with the first ungual of other theropods (e.g., bifurcation is more proximal than in abelisaurids. Sin raptor; Currie and Zhao, 1993). Phalanx K27/633, although notably compressed Moreover, current phylogenetic hypotheses (e.g., Novas, 1992;Sampson et al., 1998)depict abelisaurids transversely, has a conspicuous ventral furrow and as Cretaceous ceratosaurs, suggesting that bifurcated collateral bifurcated grooves, as the pedal unguals described above. Because K27/ 633 is nearly as large grooves on the pedal unguals were independently acquired in different theropod groups (e.g., as, albeit is transversely narrower, than the presumed ungual of digit III (K27/634; figures 2.A-D), we interAbelisauridae, Patagonykus, Troodon). 2) Presence of a rounded bump on the lateral pret K27/ 633 as belonging to digit 11.It is the deepest side of pedal unguals (figure LB). In abelisaurid un- of the available unguals, and resembles the ungual of guals the upper and lower branches of the bifurcated digit 11of Sinraptor (Currie and Zhao, 1993). Ungual lateral groove bound a triangular prominence, not K27/635 (Huene and Matley, 1933,pl. XIX,fig. 10) refound in other theropods. In coelurosaurs with "Y"- sembles K27/ 633 in its high lateral profile and asymshaped grooves, this region is less prominent or al- metry, although it is not dorsally keeled. Another ungual presumably belongs to digit IV. most flat. Phalanx K27/537 (Huene and Matley, 1933, pl. XIX, 3) Ventral surface excavated or with a narrow and deep furrow (figure 1.D). This character seems fig. 12) shows the same curvature in lateral view, and to be unique of abelisaurid theropods. In most has a similar profile in cross-section. Ungual K27/ 629 A.P.A. Publicación Especial 7, 2001 148zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA F.E. Navas and S. BandyapadhyayXWVUTSRQPONMLKJIHGFEDCBA A E F e o Figure 2. A-F, abelisaurid unguals from the Lameta Formation (Maastrichtian) of Central India. A-D, pedal ungual (K27/634) presumably corresponding to digit III, and E-F, pedal ungual (K27/524) presumably corresponding to digit IV. A and E, lateral, B, dorsal, C, ventral, and F and D, proximal views. Scale bar: 2 cm. A.P.A. Publicación Especial 7, 2001 Abelisaurid pedal unguals from India 149 middle Cretaceous of Patagonia. Contributions (Huene and Matley, 1933, pl. XXIV,fig. 20) may also Natural History Museum 01 Los Angeles County 416: belong to digit IV.ZYXWVUTSRQPONMLKJIHGFEDCBA in Science, 1-42. Chatterjee, S. 1978. lndosuchus and lndosaurus, Cretaceous carnosaurs from India. [curnal 01 Paleontology 52: 570-580. Chatterjee, S. and Rudra, D. 1996. KT events in India: impact, rifting, volcanism and dinosaur extinction. Proceedings of the Gondwanan Dinosaur Symposium. Queensland M useum, C o n c lu s io n s Peculiar theropod pedal unguals from the Lameta Memoirs 39: 489-532. Formation are different from those of other Currie, P. and Zhao, X.-J. 1993. A new carnosaur (Dinosauria, Theropoda) from the Jurassic of Xinjiang, People's Republic of theropodsonmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (e.g., Allosaurus, Sin raptor, TyrannoChina. Canadian [ournal 01 Earth Sciences 30: 2037-2081. sauridae, Ornithomimidae, Troodontidae, DromaeoHuene, P. and Matley, C. 1933. The Cretaceous Saurischia and sauridae, Alvarezsauridae) in the presence of proxiOrnithischia of the Central Provinces of India. Memoir 01 mally bifurcated grooves, a rounded bump on the Geological Suroey 01 India 21: 1-72. Madsen, J.H. 1976. Allosaurus jragilis: a revised osteology. Utah lateral side of pedal unguals, and a narrow and deep Geological and Mineral Suroev, Bulletin 109:1-163. furrow on the ventral surface. This set of derived feaMartínez, R, Giménez, O., Rodríguez, J. and Bochatey, G. 1986. tures is shared with a new Patagonian abelisaurid Xenotarsosaurus bonapartei gen. et. sp. nov. (Carnosauria, (MCA 56), suggesting that the unguals originally deAbelisauridae), un nuevo Theropoda de la Formación Bajo Barreal, Chubut, Argentina. 4° Congreso Argentino de scribed by Huene (in Huene and Matley, 1933) bey Bioestratigrafía (Mendoza), Actas 2: 23-31. Paleontología XWVUTSRQPONMLKJIHGFEDCBA long to Abelisauridae. This evidence is consistent Molnar, RE. 1990. Problematic Theropoda: "Carnosaurs". In: D.B. with the remarkable abundance of abelisaurid reWeishampel, P. Dodson and H. Osmólska (eds.), The mains documented in the same quarry at Bara Simla Dinosauria, pp. 306-317. University of California Press, Berkeley. Hill (Chatterjee and Rudra, 1996; Novas and Norman, D. 1990. Problematic Theropoda: "Ceolurosaurs". In: Bandyopadhyay, 1999). D.B. Weishampel, P. Dodson and H. Osmólska (eds.), The Differences in absolute size, degree ofaxial asymDinosauria, pp. 280-305. University of California Press, metry, transverse width, dorsoventral height, and Berkeley. Novas, P.E. 1992. La evolución de los dinosaurios carnívoros. In: depth of the ventral furrow that were originally notJ.L. Sanz y A. Buscalioni (eds.), Los dinosaurios y su entorno ed for the Indian unguals (Huene and Matley, 1933), biótico. Actas 2° Curso de Paleontología en Cuenca, pp. 125may represent different pedal digits of individuals of 163. Instituto "Juan de Valdés", Ayuntamiento de Cuenca, different size. At this moment, we are not able to deEspaña. Novas, P.E. 1997. "Abelisauridae". In: P. Currie and K. Padian termine if the unguals from Bara Simla Hill corre(eds.), Encyclopaedia 01 Dinosaurs, pp. 1-2. Academic Press. spond to a single abelisaurid species. Acknowledgements We thank Mr. S. Apesteguía, discoverer of the new Patagonian specimen, the Director of the Geological Survey of India, Calcutta for allowing access to the collections, Dr. C. Forster (Sta te University of New York, Stony Brook) for allowing access to Majungatholus specimens under her care, and Dr. M. Norell for theropods specimens at the American Museum of Natural History, New York. The original draft of this paper was improved thanks to the reviews of Dr. P. Currie (Royal Tyrrell Museum of Palaeontology, Calgary) and Dr. S. Chatterjee (Texas Tech University, Lubbock). Drawings were skillfully executed by J.A. González. The Agencia Nacional de Promoción Científica y Técnica (Buenos Aires) financed the field trip to Rio Negro and subsequent research. The Antorchas Foundation (Buenos Aires) and The Dinosaur Society (USA) covered the study trip of P.E.N. to India. The Jurassic Foundation (Calgary) funded studies on abelisaurid phylogeny. Novas, P.E. and S. Bandyopahyay. 1999. New approaches on the Cretaceous theropods from India. 7° International Symposium on Mesozoic Terrestrial Ecosystems (Buenos Aires), Abstract: 4647. Romer, A.5. 1956. Osteology 01 ihe Reptiles. University of Chicago Press, 772 p. Sampson, S., Witmer, L., Forster, c . , Krause, D., O'Connor, P., Dodson, P. and Rovoavy, P. 1998. Predatory dinosaur remains from Madagascar: implications for the Cretaceous biogeography of Gondwana. Science 280: 1048-1051. Walker, A.D. 1964. Triassic reptiles from the Elgin area: Drnithosuchus and the origin of the carnosaurs. Phiioeophical Transactions 01 the Royal Society 01 London B 248: 53-134. References Bonaparte, J.F and Novas, P.E. 1985. Abetisaurus comahuensis, n. g. et n. sp., Carnosauria del Cretácico Tardío de Patagonia. Ameghiniana 21: 259-265. Bonaparte, J.P. and Powell, J.E. 1980. A continental assemblage of tetrapods from the Upper Cretaceous beds of El Brete, northwestem Argentina. Mémoires de la Société Géologique de France, n. ser. 139: 19-28. Bonaparte, J.P., Novas, P.E. and Caria, RA. 1990. Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Accepted: December 20th, 2001. A.P.A. Publicación Especial 7, 2001