A Primitive Therizinosauroid Dinosaur from the Early Cretaceous of Utah

Home , Beipiaosaurus, Eshanosaurus, Falcarius, Incisivosaurus, Therizinosauridae, Therizinosaurus

letters to nature

23. ABAQUS/Standard, User’s Manual, version 6.3 (Hibbitt, Karlson and Sorenson Inc., Pawtucket, Holotype. Utah Museum of Natural History; UMNH VP 15000 Rhode Island, 2002). partial braincase (Fig. 1b, c). 24. Ellis, S. & Sto¨ckhert, B. Elevated stresses and creep rates beneath the brittle-ductile transition caused by seismic faulting in the upper crust. J. Geophys. Res. 109, B05407, doi:10.1029/2003JB002744 (2004). Referred specimens (paratypes). Utah Museum of Natural His- 25. Watts, A. B. Isostasy and Flexure of the Lithosphere (Cambridge Univ. Press, Cambridge, UK, 2001). tory; UMNH VP 12279-12443, 14524-14999, 15001-15149. 26. Wu, P. & Hasegawa, H. S. Induced stresses and fault potential in eastern Canada due to a disc load: a Horizon and locality. The Crystal Geyser Quarry, Grand County, preliminary analysis. Geophys. J. Int. 125, 415–430 (1996). Utah, lies at the base of the Cedar Mountain Formation, directly but 27. Stewart, S., Sauber, J. & Rose, J. Glacio-seismotectonics: ice sheets, crustal deformation and seismicity. Quat. Sci. Rev. 19, 1367–1389 (2000). disconformably overlying the Upper Jurassic Morrison Formation 28. Wu, P.,Johnston, P.& Lambeck, K. Postglacial rebound and fault instability in Fennoscandia. Geophys. (UMNH VP locality no. 157). The basal Yellow Cat Member is J. Int. 139, 657–670 (1999). estimated to be Barremian in age on the basis of the preserved 29. Hughen, K. et al. 14C activity and global carbon cycle changes over the past 50,000 years. Science 303, 202–207 (2004). dinosaur fauna (the polacanthine ankylosaur Gastonia, the ornitho- 30. Smith, R. B. et al. Geophysical and tectonic framework of the eastern Basin and Range-Colorado pod ‘Iguanodon’, three species of sauropods, and large and small Plateau-Rocky Mountains transition. Geol. Soc. Am. Mem. 172, 205–233 (1989). theropods such as Utahraptor and Nedcolbertia4,5), charophytes4 and palynomorphs (D. Eberth and B. Britt, personal communication Acknowledgements We thank A. Friedrich and A. Densmore for discussions. R.H. was supported 2004). by a Heisenberg fellowship from the German Research Foundation (DFG). Diagnosis. Falcarius is a maniraptoran theropod diagnosed by the following suite of unique characters from holotype braincase: Competing interests statement The authors declare that they have no competing financial interests. expansive, open pneumatic cavities in basioccipital and basisphenoid with the basisphenoidal recess directed ventrally; and extensive Correspondence and requests for materials should be addressed to R.H. subcondylar pneumatic recesses lateral to the occipital condyle. ([email protected]). From paratype elements: presence of one enlarged tooth at anteriormost end of dentary; laterally deflected and biconcave apex of the deltopectoral crest; posterior tuberosity on the distal end of the humerus opposite the radial condyle; flexor tubercle of phalanx I–II with well-defined collateral pits on the distal aspect; and the unique ...... combination of the following features: dentary lacking lateral shelf A primitive therizinosauroid dinosaur found in other therizinosauroids; mid-caudal vertebrae elongate with zygapophyses less than one-third the length of centrum as from the Early Cretaceous of Utah opposed to shortened vertebrae in other therizinosauroids and oviraptorosaurs. James I. Kirkland1, Lindsay E. Zanno2, Scott D. Sampson2, Description. Falcarius is a gracile, small- to medium-sized thero- James M. Clark3 & Donald D. DeBlieux1 pod, approximately 1 m in height at hips and 4 m in length. The specimens referred to this taxon account for approximately 90% of 1Utah Geological Survey, PO Box 146100, Salt Lake City, Utah 84114-6100, USA the skeleton (Figs 1 and 2). 2Utah Museum of Natural History and Department of Geology and Geophysics, Skull material is underrepresented and currently includes a left University of Utah, 1390 E. Presidents Circle, Salt Lake City, Utah 84112-0050, maxilla, right postorbital, paired frontals, two braincases, isolated USA juvenile basiocciput, left and right quadrates, one left and two right 3George Washington University, Washington DC 20052, USA dentaries, and a right splenial. As in Erlikosaurus6, the number of ...... maxillary neurovascular foramina is reduced to approximately one Therizinosauroids are an enigmatic group of dinosaurs known slit-like foramen for every three alveoli. The quadrates are anteriorly mostly from the Cretaceous period of Asia, whose derived arched with large pneumatic fossae. The frontals are subrectangular, members are characterized by elongate necks, laterally expanded as in dromaeosaurids and oviraptorosauroids, with similarly pelves, small, leaf-shaped teeth, edentulous rostra and mandi- inflated cerebral fossa (Fig. 1). The fossa for the olfactory bulb is 1,2 bular symphyses that probably bore keratinized beaks . approximately two-thirds as wide as the cerebral fossa. The par- Although more than a dozen therizinosauroid taxa are known, occipital processes are more slender and elongate than in derived their relationships within Dinosauria have remained controver- therizinosauroids and are pneumatized via caudal tympanic sial because of fragmentary remains and an unusual suite of recesses (Fig. 1). The basioccipital is pocketed ventrolaterally by characters. The recently discovered ‘feathered’ therizinosauroid extensive subcondylar recesses that encompass two openings for Beipiaosaurus from the Early Cretaceous of China helped to cranial nerves X–XI and a single opening for XII. Falcarius lacks a clarify the theropod affinities of the group3. However, Beipiao- dorsoventral expansion of the paroccipital process and a ventral saurus is also poorly represented. Here we describe a new, pneumatic inflation of the basisphenoid, the derived condition primitive therizinosauroid from an extensive paucispecific found in both Erlikosaurus6 and Nothronychus7. bonebed at the base of the Cedar Mountain Formation (Early The dentary deepens posteriorly, but lacks the lateral shelf and Cretaceous) of east-central Utah4,5. This new taxon represents down-turned symphyseal region possessed by all other known the most complete and most basal therizinosauroid yet discov- therizinosauroids2,3,6 (Fig. 2). The dentary is medially curved ante- ered. Phylogenetic analysis of coelurosaurian theropods incor- riorly, indicating the presence of a U-shaped snout as in other porating this taxon places it at the base of the clade therizinosauroids2,6 and oviraptorosaurs8. Therizinosauroiden, indicating that this species documents the The dentary teeth share several features with the teeth of other earliest known stage in the poorly understood transition from therizinosauroids (Fig. 2). Similarities include posteriorly small, carnivory to herbivory within Therizinosauroidea. The taxon lanceolate and basally constricted crowns that become taller ante- provides the first documentation, to our knowledge, of therizi- riorly, as well as the presence of inflated, circular roots. Also, in nosauroids in North America during the Early Cretaceous. contrast to other therizinosauroids, conical teeth are present in Theropoda Marsh 1881 the anteriormost portion of the dentary in Falcarius. The first Coelurosauria von Huene 1914 alveolus of the dentary is hypertrophied and apparently housed a Therizinosauroidea Maleev 1954 tooth with twice the cross-sectional area of more posterior tooth Falcarius utahensis gen. et sp. nov. positions. This condition is comparable to the enlarged pre- Etymology. From Falcarius (Latin, a sickle-maker) and utahensis maxillary teeth of the primitive oviraptorosaur Incisivosaurus (refers to Utah as its place of origin). (¼?Protoarchaeopteryx9), although its anterior dentary is

letters to nature edentulous10. The preserved teeth of the fragmentary maxilla the condition in derived oviraptorosaurs13 and derived therizino- have lower tooth crowns that decrease in size posteriorly (Fig. 2). sauroids2,13. The denticles on all teeth are small (7–10 mm21), unlike other The coracoids are strongly recurved with a pronounced ventral therizinosauroids (Fig. 2). tubercle. As in more derived therizinosauroids, the humeri have an The vertebral column is well represented with the exception of the angular internal tuberosity, cranially positioned distal condyles and axis. Anterior cervical centra are amphicoelous, elongate (length a hypertrophied entepicondyle1,2. The humeral shaft lacks both four times height) and highly pneumatized, with multiple, small the posterior tuberosity of more derived therizinosaurids1,2,16–19 pneumatic foramina. As in derived therizinosauroids2,11–13 and and the anterior tuberosity proximal to the entepicondyle of oviraptorosaurs14, cervical neural arches are low and elongate and Neimongosaurus15 and Erliansaurus20. The ulna is bowed with a zygapophyses become more widely spaced posteriorly (giving the robust olecranon process. The radius is straight and lacks the biceps neural arch an X-shape in dorsal view). Dorsal neural arches have tubercle seen on Neimongosaurus15. The manus is relatively gracile large transverse processes supported by multiple laminae, short and elongate, as in Beipiaosaurus3 and many oviraptorosaurs14 neural spines that thicken dorsally, and thick hyposphene– (Fig. 1). Distal carpals are preserved in two morphs: one fused hypantrum articulations. There are ﬁve sacral vertebrae as in into a semilunate that caps metacarpals I and II, and the other as Alxasaurus12, in contrast to six preserved in Neimongosaurus15 and unfused pairs of distal carpals as in other therizinosauroids2. Segnosaurus16, with the intermediate three possessing pneumatic Metacarpal I exhibits a rectangular buttress on its proximoventral fossae. Medial to distal caudals are more than four times as long as surface, similar to that of Alxasaurus12. high. All caudal vertebrae seem to be apneumatic with loss of caudal The pelvis is primitive in that the ilium is relatively elongate ribs and neural spines distal to caudals 11–13 (Fig. 1), in contrast to anteroposteriorly, with a parasagittal dorsal margin lateral to the

Figure 1 Skeletal elements of Falcarius utahensis. a, b, Holotype braincase UMNH-VP reconstruction; h, reconstructed left foot UMNH-VP 12330–12342, 12352–12356 in 15000 in posterior (a) and lateral (b) views; c, paired frontals UMNH VP 14524, 14525 in anteriodorsal view; i, medial caudal vertebrae UMNH VP 12405, 12407, 12409 with ventral view; d, e, left ilium UMNH VP12368 in dorsal (d) and lateral (e) views; chevron UMNH VP12391 in lateral view. bptp, basipterygoid process; br, basisphenoidal f, reconstructed right pectoral girdle UMNH VP 12279, 12281 and forelimb UMNH VP recess; bt, basitubera; ctr, caudal tympanic recess; f, fenestra ovalis and fenestra 12284, 12287, 12289, 12291, 12294–12296, 12298, 12300, 12302, 12314, 12304, pseudorotunda; j, jugular foramina; m, metotic ﬁssure; pr, prootic recess; sor, subotic 12306, 12308, 12310, 12312, 12316, 12320 in lateral view; g, Falcarius skeletal recess; sr, subcondylar recess; roman numerals represent cranial nerves.

letters to nature sacral transverse processes (Fig. 1), the pubis has not rotated to an condition. Falcarius demonstrates the mosaic nature of this evol- opisthopubic condition, and the obturator process does not contact utionary transition, indicating that the dentition and pelvis were the pubis. The pubic peduncle is also primitive, being wide and among the first hard-tissue structures to undergo modification. dorsoventrally shallow. Derived therizinosauroid characters of the These changes probably coincided with modifications in food pelvis include a deep, strongly hooked and laterally flaring pre- acquisition and digestion during the early stages of therizinosauroid acetabular process, and a dorsoventrally shortened postacetabular process of the ilium2. The acetabulum of Falcarius is anteriomedially directed, a condition also present in Neimongosaurus15. As with the forelimb, the hindlimb of Falcarius is relatively elongate and slender, with an anteriorly bowed femur estimated at approximately 85% tibial length. The lesser trochanter is alar, separated from the greater trochanter by a deep, narrow cleft. The tibia is gracile with a pronounced fibular crest. As in other therizinosauroids2,3,12,13, the proximal fibula lacks the medial fossa found on most maniraptorans. The distal tibia is surrounded by the astragalus, unlike the reduced condition in other therizinosauroids2. The ascending process of the astragalus is tall and nearly symmetri- cal, unlike the shortened, asymmetrical morphology of Therizino- saurus21. The functionally tridactyl pes is similar to that of Beipiaosaurus3 and oviraptorosaurs14 and unlike the functionally tetradactyl pes of all other known therizinosauroids1,2 (Fig. 1). A phylogenetic analysis (Fig. 3) provides strong support for the hypothesis that Falcarius is the basalmost therizinosauroid known. Falcarius possesses several maniraptoran synapomorphies not previously documented in basal therizinosaurs, including hypapo- physes on the presacral vertebral column, bowed ulna, presence of a semilunate comprised of fused distal carpals one and two, ischium less than two-thirds pubis length, and distally positioned obturator process of the ischium22–25. Therizinosaurs are here proposed as shifting their dietary habit from predation to herbivory on the basis of the development of a number of features that seem convergent with clades of other herbivorous dinosaurs. The most significant of these features include small, leaf-shaped teeth, an edentulous beak, posterior displacement of the pubis and lateral expansion of the pelvis associated with greatly increased intestinal volume1,26, and shortening of the tibia relative to the femur and an increased number of weight-supporting pedal digits—the latter two being specific reversals of the cursorial

Figure 3 Phylogenetic relationships of Falcarius among the Coelurosauria. Strict Figure 2 Jaws and teeth of Falcarius utahensis. a, Partial left maxilla UMNH VP 14526 in consensus of 5,000 trees with the following statistics: treelength 679; Consistency Index, lateral view; b, c, close-up of maxillary teeth in lingual (b) and labial (c) views; d, detail of 0.41; Retention Index, 0.74; Rescaled Consistency Index, 0.31. maxillary tooth denticles in labial view; e, dentary teeth UMNH VP 14527 in lingual view; Therizinosauroidea þ Oviraptorosauria (node 1), Therizinosauroidea (node 2): f, detail of dentary tooth denticles in labial view; g, same dentary teeth in labial view; Therizinosauroidea more derived than Falcarius (node 3). Character states deﬁning these h, composite reconstruction of the dentary of Falcarius based on UMNH VP 14527, UMNH nodes are discussed in Methods. Advent of dietary shift from carnivory to herbivory is VP 14528 and UMNH VP 14529. nf, nutritive foramina. postulated to occur at base clade 1 (shaded black).

letters to nature evolution. Moreover, similarities between the dentition of the basal 11. Dong, Z. & Yu, H. in Sino-Japanese Silk Road Dinosaur Expedition (ed. Dong, Z.) 90–95 (China Ocean Press, Beijing, 1997). therizinosaur Falcarius and the basal oviraptorosaur Incisivosaurus, 12. Russell, D. A. & Dong, Z.-M. The affinities of a new theropod from the Alxa Desert, Inner Mongolia, in combination with their proposed sister relationship (Fig. 3), People’s Republic of China. Can. J. Earth Sci. 30, 2107–2127 (1993). raises the possibility that the common ancestor of these clades had 13. Kirkland, J. I. & Wolfe, D. G. First definitive therizinosaurid (Dinosauria; Theropoda) from North already undertaken the initial steps in this transition. America. J. Vertebr. Paleont. 21, 410–414 (2001). 14. Osmolska, H., Currie, P. J. & Barsbold, R. in The Dinosauria II (eds Weishampel, D. B., Dodson, P. & The Early Jurassic Chinese jaw from the Lufeng Series in southern Osmolska, H.) 165–183 (Univ. California Press, Berkeley, 2004). China described tentatively as the basal therizinosauroid Eshano- 15. Zhang, X.-H. et al. A long-necked therizinosauroid dinosaur from the Upper Cretaeous Iren Dabasu saurus27 is more derived in having a lateral shelf and down-turned Formation of Nei Mongol, People’s Republic of China. Vertebr. PalAsiatica 10, 282–290 (2001). symphysis, which are absent in Falcarius. Its therizinosauroid 16. Perle, A. Segnosauridae—a new family of theropods from the Late Cretaceous of Mongolia. Trans. Joint Soviet-Mongolian Palaeont. Exped. 8, 45–55 (1979). identification have been considered problematic by some 17. Barsbold, R. New information on Therizinosaurus (Therizinosauridae, Theropoda). Trans. Joint 13,25 authors . Falcarius casts further doubt on the affinities of Soviet-Mongolian Palaeont. Exped. 3, 76–92 (1976). Eshanosaurus by increasing its stratigraphic and phylogenetic 18. Perle, A. A new segnosaurid from the Upper Cretaceous of Mongolia. Trans. Joint Soviet-Mongolian Palaeont. Exped. 15, 45–55 (1981). inconsistency. Given the discovery of North American members 19. Mader, B. J. & Bradley, R. L. A redescription and revised diagnosis of the syntypes of Alectrosaurus of the therizinosauroid clade, together with the poor record of olseni. J. Vertebr. Paleont 9, 41–55 (1989). Middle Cretaceous dinosaurs, it seems that the generally 20. Xu, X. et al. A new therizinosauroid (Dinosauria, Theropoda) from the Upper Cretaceous Iren Dabasu accepted hypothesis of an Asian origin and radiation for Therizi- Formation of Nei Mongol. Vertebr. PalAsiatica 40, 228–240 (2002). 1,2 A 21. Perle, A. On a new finding of the hindlimb of Therizinosaurus sp. from the Late Cretaceous of nosauroidea requires additional testing. Mongolia. Probl. Geol. Mongol. 5, 94–98 (1982). 22. Gauthier, J. A. Saurischian monophyly and the origin of birds. Mem. Calif. Acad. Sci. 8, 1–55 (1986). Methods 23. Holtz, T. R. A new phylogeny of the carnivorous dinosaurs. Gaia 15, 5–61 (2000). Collections from the Crystal Geyser Quarry made so far preserve a minimum of ten 24. Norell, M. A., Clark, J. M. & Makovicky, P. J. in New Perspectives on the Origin and Early Evolution of individuals based on prepared femora, but the quarry size indicates that perhaps hundreds Birds (eds Gauthier, J. & Gall, L. F.) 49–67 (Peabody Museum of Natural History, New Haven, 2001). of disarticulated individuals remain interred, representing multiple growth stages as well 25. Rauhut, O. W. M. The interrelationships and evolution of basal theropod dinosaurs. Spec. Pap. as robust and gracile morphotypes. The locality spans about 8,000 m2 and the bone- Palaeont. 69, 1–213 (2003). 26. Paul, G. S. The segnosaurian dinosaurs: relics of the prosauropod–ornithischian tranisition. J. Vertebr. bearing stratum is, on average, 1 m thick, with bone densities in some areas exceeding 100 Paleont. 4, 507–515 (1984). elements per cubic metre. There is no evidence of another small theropod taxon, so all of 27. Xu, X., Zhao, X. & Clark, J. M. A new therizinosaur from the Lower Jurassic Lufeng Formation of the therizinosauroid materials are here referred to Falcarius. In addition to the Yunnab, China. J. Vertebr. Paleont. 21, 477–483 (2001). therizinosauroid elements, the quarry contains rare remains of an unidentified ankylosaur. 28. Swofford, D. L. PAUP* Phylogenetic Analysis Using Parsimony (*and Other Methods), version 4.0b10 About 99% of all identified bones from the type locality (about 2,000 identifiable bones) (Sinauer Associates, Sunderland, Massachusetts, 2002). represent Falcarius. Several features of these fossils, including neurocentral fusion and fusion of cervical ribs to the vertebrae, indicate that the largest elements represent adult or near-adult Supplementary Information accompanies the paper on www.nature.com/nature. individuals. Dorsal ribs and gastralia are the most poorly represented with only two dorsal ribs and one gastralia identified, although many bone fragments in the quarry are thought Acknowledgements We thank X. Xu, Z. Dong, P. Sereno and M. Norell for access to reference to be unidentifiable pieces of rib. There are multiple examples of nearly all bones, although material; G. Paul for executing the skeletal reconstruction of Falcarius; The Utah Friends of much excavation and preparation remains before a detailed taphonomic analysis can be Paleontology, the Utah Museum of Natural History, and H. and P.Bollan for assistance in the field attempted. Overlapping examples of the largest elements are close to the same size, and the laboratory; M. Hayden, M. Christopher, M. Suarez and C. Suarez for overseeing the indicating that mature animals had restricted growth. Additionally, associated elements volunteers in the field; J. R. Scandizzo for introductions to the site discoverer L. Walker of Moab, (particularly appendicular elements) indicate the relative proportions of skeletal elements Utah; R. W. Gaston for providing research casts; D. Smith for comments on theropod braincase in some individuals. The skeletal reconstruction of Falcarius in Fig. 1 was based on the anatomy; and J. Harris, M. Hayden, M. Lowe and M. Hylland for reviewing the manuscript. largest preserved elements in the quarry, with vertebral numbers estimated on changing Excavations were conducted under a US Bureau of Land Management permit. Funding was proportions of the vertebrae and comparisons with other maniraptoran theropods. provided by the Utah Geological Survey, Discovery Channel Quest Grants, Paleoscene, to J.I.K. Phylogenetic relationships were analysed with the use of data from published sources and the NSF to J.M.C. supplemented with novel information (see Supplementary Information). Parsimony analysis of 57 taxa and 231 characters was performed with PAUP 4.0b10 (ref. 28), with all Competing interests statement The authors declare that they have no competing financial characters weighted equally and a single character ordered, using Allosaurus and Sinraptor interests. as outgroups (Fig. 3). Five unambiguous synapomorphies support Therizinosauroidea: teeth serrated Correspondence and requests for materials should be addressed to J.I.K. (reversal); ventral surface of dentary descends strongly posteriorly; ventral edge of ([email protected]). anterior ala of ilium hooked anteriorly; distal humerus with large medial condyle, centred on distal end; and preacetabular portion of ilium laterally flaring. The basal position of Falcarius is supported by the absence of the following characters: labial face of dentary with lateral ridge and inset tooth row; interdental plates on dentary; obturator process of ischium does not contact pubis; metatarsal I without proximal articulating surface...... Therizinosauroidea þ Oviraptorosauria characterized by basipterygoid processes abbreviated or absent; suborbital fenestra reduced in size or absent; basipterygoid Discovery of the first Asian processes hollow; symphyseal region of dentary strongly recurved; maxillary and dentary teeth lanceolate and subsymmetrical. plethodontid salamander Received 10 December 2004; accepted 17 February 2005; doi:10.1038/nature03468. 1 2 3 3 4 1. Maryanska, T. in The Complete Dinosaur (eds Farlow, J. O. & Brett-Surman, M. K.) 234–241 (Indiana M. S. Min , S. Y. Yang , R. M. Bonett , D. R. Vieites , R. A. Brandon Univ. Press, Bloomington, 1997). & D. B. Wake3 2. Clark, J. M., Maryanska, T. & Barsbold, R. in The Dinosauria II (eds Weishampel, D. B., Dodson, P. & Osmolska, H.) 151–164 (Univ. California Press, Berkeley, 2004). 1Conservation Genome Resource Bank for Korean Wildlife, and Brain Korea 21, 3. Xu, X., Tang, Z.-L. & Wang, X.-L. A therizinosauroid dinosaur with integumentary structures from China. Nature 399, 350–354 (1999). School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, 4. Kirkland, J. I., et al. in Vertebrate Paleontology in Utah (ed. Gillette, D.) 201–217 (Utah Geol. Surv. South Korea 2 Misc. Pub. 99-1, Salt Lake City, 1999). Department of Biology, Inha University, Incheon 402-751, South Korea 5. Kirkland, J. I. Utah’s newly recognized dinosaur record from the Early Cretaceous Cedar Mountain 3Museum of Vertebrate Zoology and Department of Integrative Biology, University Formation. Utah Geol. Surv. Surv. Notes 37, 1–5 (2005). of California, Berkeley, California 94720, USA 6. Clark, J. M., Perle, A. & Norell, M. A. The skull of Erlicosaurus andrewsi, a Late Cretaceous ‘segnosaur’ 4Department of Zoology, Southern Illinois University, Carbondale, Illinois 62901, (Theropoda: Therizinosauridae) from Mongolia. Am. Mus. Novit. 3115, 1–39 (1994). 7. Kirkland, J. I. & Wolfe, D. G. A therizinosaurid (Dinosauria: Theropoda) braincase from the middle USA Turonian (Cretaceous) of North America. J. Vertebr. Paleont. 21, 68A (2001)...... 8. Sues, H.-D. On Chirostenotes, a Late Cretaceous oviraptorosaur (Dinosauria: Theropoda) from Nearly 70% of the 535 species of salamanders in the world are western North America. J. Vertebr. Paleont. 17, 698–716 (1997). members of a single family, the Plethodontidae, or lungless 9. Senter, P., Barsbold, R., Britt, B. B. & Burnham, D. A. Systematics and evolution of Dromaeosauridae salamanders1. The centre of diversity for this clade is North (Dinosauria, Theropoda). Bull. Gunma Mus. Nat. Hist. 8, 1–20 (2004). 10. Xu, X., Cheng, Y.-N., Wang, X.-L. & Chang, C.-H. An unusual oviraptorosaurian dinosaur from and Middle America, where the vast majority (99%) of species are China. Nature 419, 291–293 (2002). found. We report the discovery of the first Asian plethodontid