Journal of Vertebrate Paleontology 20(2):404–407, June 2000 䉷 2000 by the Society of Vertebrate Paleontology
NOTE
A NEW GENUS OF DROMAEOSAURIDAE (DINOSAURIA, THEROPODA) FROM THE UPPER CRETACEOUS OF FRANCE RONAN ALLAIN and PHILIPPE TAQUET, URA 12 du CNRS, Laboratoire de Pale´ontologie, Muse´um National d’Histoire Naturelle, 8 rue Buffon, 75005 Paris, France
Dromaeosaurid dinosaur remains are extremely rare in Europe and hitherto provide very poor taxonomic information. They are known in the Lower Maastrichtian of Portugal (Antunes and Sigogneau, 1992), in the Maastrichtian of Romania (Weishampel and Jianu, 1996) and in the Campanian–Maastrichtian of France (Buffetaut et al. 1986; Le Loeuff et al., 1992; Le Loeuff et Buffetaut, 1998). Since 1993, new discoveries of Upper Campanian to Lower Maastrichtian dinosaur remains at La Boucharde locality in the Arc Basin of southeastern France include some well-preserved, disarticulated postcranial elements of a single individual referred to the theropod family Dromaeosauridae. These fossils are the first from Europe which provide good taxonomic information and diagnostic characters for this dinosaur family. The first dromaeosaurid remains ever found in France were initially referred by Lapparent (1947:fig. 10) to Megalosaurus pannoniensis. Recently, a new dromaeosaurid, Variraptor mechinorum was named on the basis of poorly preserved material from the Upper Cretaceous of southern France. The holotypic specimen consists of the last dorsal vertebra and the sacrum discovered at the Bastide Neuve locality. However, no distinguishing features has been recognized on this holotypic material. Furthermore, the most part of the diagnosis is based on a cervico-dorsal vertebra found in another locality; Roques-Hautes. We therefore regard Variraptor mechinorum as a nomen dubium.
kilometres to the south-east of Trets, Bouches-du-Rhoˆne, France. Horizon—Fluvio-lacustrine sandstones, Begudian (Upper Campanian to Lower Maastrichtian). Associated Taxa and Local Fauna—This species occurs in association with bones of Rhabdodon priscus, nodosaurid, titanosaurid, and ceratosaurian dinosaurs, as well as dinosaurian eggshell, turtle-shell fragments (Dortoka sp., Solemys sp., Polysternon sp. and a new chelydroid turtle), and alligatorid bones. As a whole, this fauna represents a typically Late Cretaceous, west European continental vertebrate assemblage. Specific Diagnosis—Pyroraptor olympius is a small Dromaeosauridae, characterized by the occurence of a deep depression on the lateral face of the bowed ulna below its proximal extremity. The second metatarsal is ventrally concave. The large ungual claw is strongly curved. The metatarsal II is distally grooved and asymmetrical. The tooth serrations are present posteriorly but restricted on the anterior carina. The metatarsal II is subequal in length to the ulna.
SYSTEMATIC PALEONTOLOGY
DESCRIPTION
Order SAURISCHIA, Seeley, 1888 Suborder THEROPODA, Marsh, 1881 Family DROMAEOSAURIDAE, Matthew and Brown, 1922 PYRORAPTOR, gen. nov.
Pyroraptor olympius is recognizable as a Dromaeosauridae by many synapomorphic features. The elements of the second pedal digit are highly modified for predation. The shape of the ungual claw is more reminiscent of dromaeosaurids than troodontids (Currie and Peng, 1993: fig. 2). It is is laterally flattened and ventrally sharp (Fig. 1), and curved through a 140⬚ arch following the methodology described by Ostrom (1969). As in dromaeosaurids, the strongly developed flexor tubercule is situated at the proximal end of the ungual phalanx (Ostrom, 1969; Barsbold, 1983). The second phalanx of the second digit is compressed laterally in Pyroraptor and dromaeosaurids whereas it is compressed proximal–distally in most of the troodontids (Osmo´lska, 1987; Russell and Dong, 1993; Currie and Peng, 1993). Its proximal end is extended ventrally into a typical projection or heel (Ostrom, 1969) while its distal extremity bears a deeply grooved ginglymus, that extends further ventrally than dorsally in the proximal part of the bone (Ostrom, 1969), and deep, subcircular fossae for attachment of collateral ligaments on each side of the distal end (Fig. 1). The distal end of the second metatarsal is a deeply grooved and strongly asymmetrical ginglymus with a medial condyle larger than the lateral one. This feature is known only in the Dromaeosauridae (Norell and Makovicky, 1997). Unlike troodontids in which the metatarsal can be 1.5 or more times the length of the ulna (Russell and Dong, 1993), in Pyroraptor and dromaeosaurids this ratio is closer to 1. The Pyroraptor skeletal elements are quite similar in shape to those of the other dromaeosaurids. However, comparison with other dromaeosaurid species is not always possible because of the absence of comparable material in some taxa. For example, the dromaeosaurid from the Maastrichtian of Romania, recently described as closely related to Saurornitholestes langstoni (Weishampel and Jianu, 1996), is only known from one frontal and two fused parietals. The dromaeosaurid from Sudan could be related to Saurornitholestes as well, on account of the arrangement of the claw grooves and occurrence of a second
Type Species—Pyroraptor olympius, sp. nov. Etymology—From Greek pyros, fire and Latin raptor, thief, alluding to the fact that this new, agile small theropod has been discovered after a forestfire. Generic Diagnosis—Same as for the type species, by monotypy.
PYRORAPTOR OLYMPIUS, sp. nov. (Fig. 1A–E) Holotype—MNHN BO001, a complete ungual phalanx of left second pedal digit, housed in the collection of the Laboratoire de Pale´ontologie, Muse´um National d’Histoire Naturelle, Paris. Paratypes—MNHN BO002, a second phalanx of right second pedal digit; BO003, left second metatarsal; BO004, a complete ungual phalanx of right second pedal digit; BO005, right ulna; BO014, BO015, teeth. Etymology—From Latin olympius, from Olympus. The specific name makes an allusion to the Mont Olympe (Provence) at the foot of which is situated the new locality. Referred Material—MNHN BO006, BO007, BO008, BO009, BO010 pedal phalangeal elements; BO011, manual phalanx; BO012, distal end of first metacarpal; BO013, right radius; BO016, anterior caudal vertebra; BO017, dorsal vertebra. Locality—The material was collected in La Boucharde, two
404
NOTES
405
FIGURE 1. Pyroraptor olympius, gen et sp. nov., Upper Campanian–Lower Maastrichtian (Begudian), La Boucharde, Bouches-du-Rhoˆ ne, France. A, teeth (MNHN BO014; BO015); B, ungual of left second pedal digit in lateral view (BO001); ungual (BO0004) and second phalanx (BO002) of right second pedal digit in medial view; C, right ulna (BO004) and radius (BO013) in lateral view; D; second left metatarsal (BO003) in medial view; E, anterior caudal vertebra (BO017) in lateral and dorsal view. Abbreviations: br, attachment area for the brachialis muscle; ch, chevron facet; ns, neural spine; trp, transverse process, prz, prezygapophysis; pz, postzygapophysis. Scale bars equal 1 cm.
406
JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 20, NO. 2, 2000
claw groove dorsally to the main one in the proximal part of the claw (Rauhut and Werner, 1995). Second Left Ungual Phalanx—The complete ungual phalanx of left digit II is 66mm long on its dorsal margin and 18 mm high, 7 mm wide at the proximal end. The ungual is flatenned laterally, strongly curved and has a tall, narrow cross-section (Fig. 1B). The articular facet shows two asymetrical concavities divided by a vertical ridge. In proximal view, the left side is wider than the right one. The arrangement of the claw grooves is asymmetrical, with a medial groove ending in dorsal position at the tip of the claw. Only the claw of Pyroraptor could be compared to the Saurornitholestes langstoni material (Sues, 1978; Currie, 1995). It is more similar to the ungual of this species, first referred to Dromaeosaurus (Colbert and Russell, 1969), than to that of Deinonychus, being more trenchant ventrally and less recurved. Second Right Phalanx of Second Digit—The phalanx II2 is 23 mm long, 8 mm wide at the proximal and 6,2 mm wide at the distal end.The proximal end is characterised ventrally by the proximal heel found in troodontids and dromaosaurids (Ostrom, 1969; Barsbold, 1983). The ridge dividing the proximal articular facet continues on to the heel. The phalanx is compressed laterally. The distal extremity is narrower than the proximal one. It bears a deeply grooved gynglimus with a large radius of curvature. The collateral ligament fossae on each side of the distal end are dorsally thrown off centre (Fig. 1B). Second Left Metatarsal—The second metatarsal, which is 118.7 mm long, 16.6 mm wide at the proximal end and 12.7 mm wide at the distal end, differs from those of other Dromaeosauridae in being ventrally concave (Fig. 1D). It is long and rather stout. The proximal end is expanded into a large and slighty concave articular surface. It is semicircular in outline because of the presence of a triangular ventrolateral facet representing the appositional surface for the third metatarsal. The lateral surface is flattened where it is apressed against metatarsal III. The distal extremity, as in the other Dromaeosauridae, is a deeply grooved, asymmetrical ginglymus, with a medial condyle much smaller than the lateral one (Ostrom, 1969). Right Ulna—Measurements of the ulna are: length, 112.8 mm; greatest proximal width, 13.5 mm; greatest distal width, 15 mm; least diameter of shaft, 5.5 mm. The ulna is moderately slender with a markedly anterior concavity common among the maniraptoran (Russell and Dong, 1993). The shaft is oval in section near the midlength, and becomes triangular proximally and subcircular distally. The proximal articular surface is inclined anteriorly toward the radius. It is triangular in shape and slightly concave with a medial margin higher than the lateral one. Anteriorly to the articular surface, a broad concavity marks the appositional surface of the radius. The deep depression on the lateral face of the ulna, just below the proximal extremity is unknown in the other theropods (Fig 1C). It is interpreted here as the attachment area for the brachialis muscle, as in birds (Baumel, 1979). Thus, the function of the short, robust ridge located on the anterior face of the ulna and previously regarded as the attachment area for the brachialis muscle in Deinonychus (Ostrom, 1969) could be reconsidered. The distal extremity shows neither anteroposterior extension nor lateromedial compression, found in Deinonychus, but is expanded along an anteromedial to posterolateral axis. Teeth—The two recovered teeth are laterally compressed, sharply tapered and curved backwards (Fig. 1A). Tooth serrations extend over the entire height of the posterior margin but are restricted to the basal half part of the anterior carina. The anterior edge is more finely serrated (8 to 9 denticles per mm) than the posterior one (6 denticles per mm). Anterior Caudal Vertebra—The centrum is 24 mm long, 17 mm wide anteriorly and 16 mm wide posteriorly. The centrum is short with a roughly square cross section. Ventrally, it is marked by a shallow longitudinal groove, occupying the entire ventral surface. The ventral border of the concave intercentral articular facets are beveled to form large chevron facets. The prezygapophyseal articular facets are inclined medially with a corresponding inclination for the postzygapohyses. The broken transverse processes occupy the half of the upper lateral surfaces of the centra (Fig. 1E). DISCUSSION Dromaeosaurids are known as early as the Barremian in the United States (Utahraptor ostromayssorum) and in China (Sinornithosaurus millenii) (Kirkland et al., 1993; Xu et al., 1999), and occur in the Upper Aptian to Late Campanian of North America (Deinonychus antirrhopus, Dromaeosaurus albertensis, Saurornitholestes langstoni), the Late Santonian to Early Maastrichtian of China and Mon-
golia (Adasaurus mongoliensis, Hulsanpes perlei, Velociraptor mongoliensis) (Ostrom, 1990), and now in the Late Cretaceous of Europe (Antunes and Sigogneau, 1992; Buffetaut et al., 1986; Le Loeuff et al., 1992; Weishampel and Jianu, 1996) and Africa (Rauhut, 1995). Until now, and although the interrelationships of these species are not yet resolved, it was suggested that the Dromaeosauridae had an Early Cretaceous North American or Euramerican origin and then dispersed to Asia (Ostrom, 1990, Le Loeuff et Buffetaut, 1998). The newly discovered Early Cretaceous Chinese material (Xu et al., 1999) does not support this dispersal model. Be that as it may, European dromaeosaurids are remnants of a generalized Late Jurassic or Early Cretaceous fauna which have evolved on their own, after the late Cretaceous isolation of southern Europe. Acknowledgments—We thank Mr and Mrs Michelon for bringing their discoveries to the attention of the Muse´ um National d’Histoire Naturelle; P. Janvier, T. R. Holtz and F. Novas for critical revision of the manuscript; the Michelon family, M. Veran, V. Eisenmann, P. Richir, F. Limon, M. Fontaine, B. Battail, and J.-M. Barrat for helpful field-work; F. de Lapparent for identification of the turtle remains; D. Serrette for photographs, and F. Pilard for the preparation of figures. LITERATURE CITED Antunes, M. T., and D. Sigogneau. 1992. La faune de petits dinosaures du Cre´ tace´ terminal du Portugal. Comuncac¸ o˜ es dos Servic¸ os. Geolo´ gicos de Portugal 78:49–62. Barsbold, R. 1983.Carnivorous dinosaurs from the Cretaceous of Mongolia. Trudy, Sovmestnaya Sovetsko-Mongol’skaya Paleontologischeskaya Ekspeditsiya 19:1–117. Baumel, J. J. 1979. Osteologia; pp. 53–121 in J. J. Baumel, A. S. King, A. M. Lucas, J. E. Breazile, and H. E. Evans (eds.), Nomina Anatomica Avium. Academic Press, London. Buffetaut, E., B. Marandat, and B. Sige´ . 1986. De´ couverte de dents de Deinonychosaures (Saurischia, Theropoda) dans le Cre´ tace´ supe´ rieur du sud de la France. Comptes Rendus de l’Acade´ mie des Sciences 303:1393–1396. Colbert, E. H., and D. A. Russell. 1969. The small Cretaceous dinosaur Dromaeosaurus. American Museum Novitates 2380:1–49. Currie, P. J. 1995. New information on the anatomy and relationships of Dromaeosaurus albertensis (Dinosauria: Theropoda). Journal of Vertebrate Paleontology 15:576–591. , and J.-H. Peng. 1993. A juvenile specimen of Saurornithoides mongoliensis from the Upper Cretaceous of Nothern China. Canadian Journal of Earth Sciences 30:2224–2230. Gauthier, J. 1986. Saurischian Monophyly and the Origin of Birds; pp. 1–55 in K. Padian (ed.), The Origin of Birds and the Evolution of Flight. Memoirs of the California Academy of Sciences Number 8, San Francisco. Holtz, T. R., Jr. 1994. The phylogenetic position of the Tyrannosauridae: implications for theropod systematics. Journal of Paleontology 68: 1100–1117. Kirkland, J. I., R. Gaston, and D. Burge. 1993. A large dromaeosaur (Theropoda) from the Lower Cretaceous of Eastern Utah. Hunteria 2:1–16. Le Loeuff, J., and E. Buffetaut. 1998. A new dromaeosaurid theropod from the Upper Cretaceous of southern France. Oryctos 1:105–112. , , P. Mechin, and A. Mechin-Salessy. 1992. The first record of dromaeosaurid dinosaurs (Saurischia, Theropoda) in the Maastrichtian of southern Europe: palaeobiogeographical implications. Bulletin de la Socie´ te´ Ge´ ologique de France 163:337–343. Novas, F. E. 1998. Megaraptor namunhuaiquii, gen. et sp. nov., a largeclawed, Late Cretaceous theropod from Patagonia. Journal of Vertebrate Paleontology 18:4–9. Norell, M. A., and P. J. Makovicky. 1997. Important features of the dromaeosaur skeleton: information from a new specimen. American Museum Novitates 3215:1–28. Osmo´ lska, H. 1987. Borogovia gracilicrus gen. et sp. n., a new troodontid dinosaur from the Late Cretaceous of Mongolia. Acta Palaeontologica Polonica 32:133–150. Ostrom, J. H. 1969. Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana. Bulletin of the Peabody Museum of Natural History 30:1–165. 1976. Archaeopteryx and the origin of birds. Biological Journal of the Linnean Society 8:82–182. 1990. Dromaeosauridae; pp. 269–279 in D. B.Weishampel, P.
NOTES Dodson, and H. Osmolska (eds.), The Dinosauria. University of California Press, Berkeley. Rauhut, O. W. M., and C. Werner. 1995. First record of the family Dromaeosauridae (Dinosauria: Theropoda) in the Cretaceous of Gondwana (Wadi Milk Formation, northern Sudan). Pala¨ ontologische Zeitschrift 69:475–489. Russell, D. A., and Z.-M. Dong. 1993. A nearly complete skeleton of a new troodontid dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People’s Republic of China. Canadian Journal of Earth Sciences 30:2163–2173. Sues, H. D. 1978. A new small theropod dinosaur from the Judith River
407
Formation (Campanian) of Alberta Canada. Zoological Journal of the Linnean Society 62:381–400. Weishampel, D. B., and C.-M. Jianu. 1996. New theropod dinosaur material from the Hateg Basin (Late Cretaceous, Western Romania). Neues Jahrbuch fu¨ r Geologie und Pala¨ ontologie, Abhandlungen 200:387–404. Xu, X., X.-L. Wang, and X.-C. Wu. 1999. A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China. Nature 401:262–266. Received 29 June 1998; accepted 18 October 1999.