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ｖｅｒ／化石研究会会誌 ＰＤＦ化／０８０８００７９ 化石研究会誌４１巻１号／本文／５ ２５‐３２ 欧文 2008.09.24 09.

化石研究会会誌 Journal of Research, Vol.４１（１）,２５-３２（２００８） ［Original report］

Phylogenetic position of in with comments on the relationship of ornithomimosaurs and alvarezsaurids

KOBAYASHI, Yoshitsugu*

Abstract The phylogenetic position of Ornithomimosauria within Coerulosauria is discussed. Most of previous phylogenetic analyses suggested that Ornithomimosauria is coelurosaur ( is the most basal ). One study suggested that ornithomimosaurs and alvarezsaurids form a monophyly. This study argues an ornithomimosaurs-alvarezsaurids relationship and supports the idea that they are probably not closely related. Additional information from this study are that two characters for the ornithomimosaur-alvarezsaurid monophyly from the previous study (metacarpals I-III extent of shaft-to-shaft contact 60-70% of shafts and metacarpal I length at least 60% that of metacarapal II) are not supported (roughly 20% contact between metacarpals II and III, less than 50% shaft-to shaft contact in metacarpals I and II in some taxa, and metacarpal I in rougly 50% of metacarpal II). A phylogenetic analysis in this study suggests that the features, supporting a close relationship between ornithomimsoaurs and alvarezsaurids in the previous study are from derived ornithomimids, not primitive forms.

Key words： Dinosauria, Coelurosauria, Ornithomimosauria, , phylogeny

Introduction ornithomimosaur genera were placed in the Ornithomimosauria are a group of theropod families Harpymimidae (includes Harpymimus) dinosaurs, each of which resembles modern ground and Garudimimidae (includes ) (Barsbold, in having a -like jaw and lightly built body 1981 ; Barsbold and Perle, 1984) from with long, slender limbs (Fig. 1). The members of as well as unnamed taxa for Pelecanimimus from this group are best known from the Spain and from China (P!rez- of (Osm"lska, 1997). The Moreno et al., 1994 ; Ji et al., 2003). Barsbold first recorded ornithomimosaur is (1976) coined Ornithomimosauria, which includes velox by Marsh (1890), who established the family Pelecanimimus, Shenzhousaurus, Harpymimidae, . Since the establishment of the Garudimimidae, and Ornithomimidae (Barsbold, family, six additional genera from 1981; Barsbold and Perle, 1984; P!rez-Moreno ( and Dromiceiomimus)andAsia et al ., 1994) (Fig. 1). The definitions of Ornithomimidae (, , , and Ornithomimosauria have been consistent in and ) were assigned to it. Non-ornithomimid previous literature (Russell, 1972 ; Barsbold and

Accepted : 13th June, 2008 *Hokkaido University Museum, Hokkaido University N 10, W 8, Kita-ku, Sapporo, Hokkaido, 060-0810 Japan E-mail : [email protected]

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Outgroups Pelecanimimus Shenzhousaurus Harpymimimus (Harpymimidae) Garudimimus (Garudimimidae) Ornithomimidae

Fig. 1. Reconstruction of a Chinese ornithomimid, Sinornithomimus dongi (from Kobayashi and Lü, 2003) and a simplified of ornithomimosaurs (from Kobayashi and Barsbold, 2004).

Osm"lska, 1990 ; P!rez-Moreno et al ., 1994 ; Holtz, includes all ornithomimosaurs from the Late 1994 ; Osm"lska, 1997 ; Holtz, 1998 ; Norell et Cretaceous of North America and except al. , 2002 ; Clark et al ., 2002 ; Hwang et al ., 2002 ; Garudimimus brevipes of Mongolia (Archaeornithomimus, Kobayashi and Lü, 2003 ; Makovicky et al., 2004) Sinornithomimus, Gallimimus, Anserimimus, Struthiomimus, except for Sereno (1997 ; 1998 ; 1999). Dromiceiomimus,andOrnithomimus) (Barsbold Padian et al . (1999) used a node-based definition and Osm"lska, 1990 ; Osm"lska, 1997). In this of Ornithomimosauria : Pelecanimimus and Ornithomimus study, Ornithomimidae is based on a stem-based and all descendants of their most recent common definition as all ornithomimosaurs closer to Ornithomimus ancestor, which is similar to“Ornithomimidae”of Sereno than to Garudimimus. (1998). Based on this definition, Ornithomimosauria includes Pelecanimimus , Shenzhousaurus , Harpymimus , Phylogenetic status of Ornithomimosauria/Ornithomimidae Garudimimus, Archaeornithomimus, Sinornithomimus, in previous studies Gallimimus, Anserimimus, Struthiomimus, Dromiceiomimus, Main phylognetic analyses on Coelurosauria and Ornithomimus.“Ornithomimosauria”of Sereno are Holtz (1998), Sereno (1999), Maryanska et al. (1998) is different from this and is a stem-based (2002), and the Theropod Working Group (Norell et definition (all maniraptoriforms closer to Ornithomimus al ., 2002 ; Clark et al , 2002 ; Hwang et al ., 2002 ; than Neornithes), consisting of , Makovicky et al ., 2005 ; Norell et al ., 2006 ; Turner Alvarezsauridae, and“Ornithomimidae”(Sereno, et al ., 2007) and suggested that Ornithomimosauria/ 1999). This inconsistency in terminology is caused by Ornithomimidae are maniraptoriforms, basal to a disagreement in the phylogenetic position , , and Aves. Although of Ornithomimosauria/Ornithomimidae within their relationships with other maniraptoriforms (e.g., Coelurosauria. This study compares the difference , Tyrannosauridae, Therizinosauridae, in the phyogentic position of Ornithomimosauria/ and Alvarezsauridae) are inconsistent, the phylogenetic Ornithomimidae within Coelurosauria in previous studies status of Ornithomimosauria/Ornithomimidae is and discusses the relationships of Ornithomimosauria consistent in Maryanska et al. (2002) and the and Alvarezsauridae. Theropod Working Group, which differs from Holtz This study follows the definition of Padian (1998) and Sereno (1999) (Fig. 2). et al. (1999) for Ornithomimosauria because it In Maryanska et al . (2002) and the Theropod is concordant with the traditional usage of Working Group, Ornithomimosauria is placed higher Ornithomimosauria. Ornithomimidae traditionally than Tyrannosauridae but more basal to the rest of

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Coelophysidae Abelisaurus Megarosaurus Herrerasaurus ischigualastensis bauri A Piatnizkysaurus Tyrannosauridae C Ornithomimosauria Dromaeosauridae lithographica sanctus portentosus zoui pergracilis gobiensis "" mongoliensis IGM100/42 gracilis Ingenia yanshini Bagaraatan Ornithomimidae Pelecanimimus Tyrannosauridae Oviraptoridae Therizinosauroidea Troodontidae Allosaurus fragilis Dromaeosauridae Sinraptor dongi Tyrannosauridae Archaepteryx Coelurus fragilis Alvarezsauridae Dilong paradoxus D Compsognathidae Pelecanimimus polyodon Archaeornithomimus asiaticus Harpymimus okladnikovi Shenzhousaurus orientalis Torvosauridae Garudimimus brevipes B Spinosauridae Struthiomimus altus Gallimimus bullatus Sinraptoridae Ornithomimus edmontonicus Compsognathidae Anserimimus planinychus Ornitholestes Ornitholestes hermanni Alvarezsauridae Therizinosauridae Therizinosauroidea Alvarezsauridae Ornithomimidae Archaeopteryx lithographica prima Caudipteryx Caenagnathidae Confuciusornis sanctus Oviraptoridae grabavi Troodontidae uhkaana Dromaeosauridae Troodontidae Aves Dromaeosauridae

Fig. 2. of theropods from previous phylogenetic analyses : Holtz (1998) (A), Sereno (1999) (B), Maryanska et al. (2002) (C), and Turner et al. (2007) (D).

members of Coelurosauria (Turner et al. (2007) Tyrannosauridae, Ornithomimimosauria, the of suggested that Compsognathidae is more basal to Oviraptorosauria and Therizinosauroidea, and Ornithomimosauria). Their analyses indicate that the the clade of Dromaeosauridae and higher taxa. differences in interrelationships for higher taxa Although the relationships of these are not (especially the position of Oviraptoridae/Oviraptorosauria) resolved, it leaves a possibility of the phylogenetic do not effect on the phylogenetic position of status of Ornithomimosauria as suggested by Ornithomimosauria. Holtz’s study shows unresolved Maryanska et al . (2002) and the Theropod Working polytomy among Troodontidae, Compsognathidae, Group. Sereno’sstudy is completely different from

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the other studies. Ornithomimidae is nested within a subequal to that of the lacrimal ornithomimids. clade with Therizinosauridae and Alvarezsauridae, Prefrontal orbital flange is absent in Struthiomimus where this clade is called“Ornithomimosauria”by altus (AMNH 5339). Anterior teeth are smaller than Sereno, and Tyrannosauridae is placed higher than posterior ones in the maxilla in Pelecanimimus. Ornithomimosauria. Chevron height is no greater than twice height of corresponding neural spines in ornithomimids. Relationships of Ornithomimidae and Alvarezsauridae Dentary length relative to the lower jaw length Sereno (2001) re-evaluated the previous varies in both groups (no more than 77% in phylogenetic studies on Alvarezsauridae (e.g., Perle and 70% in Garudimimus ). A dorsal tubercle on the et al., 1993 ; Novas, 1996 ; Chiappe et al., 1996 ; proximal phalanx of manual digit I is on lateral side Forster et al ., 1998). He argued that -like characters not medial side in and is absent in in Alvarezsauridae are synapomorphies with . Ventral surface of manual ungual is Ornithomimidae and proposed that Ornithomimidae rounded in digit III of a Mongolian alvarezsaurid and and Alvarezsairidae are monophyletic, named as flat in digit I of Mononykus and Shuvuuia , convex in Ornithomimoidea, and the clade for Ornithomimoidea Patagonykus. Flexor tubercle of manual ungulas is and Therizinosauridae is called“Ornithomimosauria” faint in alvarezsaurids. Iliac blades along their dorsal (Fig. 2). margin are separated in and not clear Suzuki et al . (2002) discussed the validity of in basal alvarezsaurids. Ornithomimidae-Alvarezsauridae synapomorphies Suzuki et al. (2002) also argued that some proposed by Sereno (1999 ; 2001). Among 19 other characters are ambiguous. Maxillary and dentary putative synapomorphies, they re-evaluated 15 teeth implanted in a groove in Pelecanimimus but not synapomorphies (dorsoventrally flattened premaxillary well preserved in other toothed ornithomimosaurs internarial bar, prefrontal exposure on the roof (all teeth in sockets in Harpymimus and larger than the lacrimal, prefrontal orbital flange, Shenzhousaurus:Jiet al., 2003; Kobayashi and teeth along maxillary and dentary rows uniform in Barsbold, 2005). Both ornithomimids and alvarezsaurids size, chevron height four to five times height of have paired flexor of manual proximal corresponding neural spines, dentary length up to phalanges but their structures are too different to 80% of the lower jaw length, presence of a dorsomedial consider that as a homology. Because the degree of tubercle on the proximal phalanx of manual digit I, maximum extension of metacarpal-phalangeal joint is ventral surface of manual ungual flattened and a functional character, it is difficult to interpret. Also broad, distally placed flexor tubercle of manual this character as well as another one (metacarpal III ungulas, iliac blades deflected toward midline midshaft width 75% or more than that of metacarpal and having partial contact along their dorsal II) were not included in Sereno’s cladistic analysis. margin, maxillary and dentary teeth implanted in a Presence of a marked flexor depression proximal to groove, presence of paired flexor process of manual the distal on the manual proximal phalanges proximal phalanges, metacarpal-phalangeal joint with could be informative but it should be restricted to approximately 15 degrees maximum extension, digit I because of the condition of alvarezsaurids. metacarpal III midshaft width 75% or more than Four of 19 characters were not discussed that of metacarpal II, and presence of a marked by Suzuki et al. (2002) (paired flexor processes flexor depression proximal to the distal condyles on in manual proximal phalanges ; posteriormost the manual proximal phalanges). tooth of maxillary teeth significantly anterior Dorsoventrally flattened premaxillary internarial to posteriormost dentary tooth ; metacarpals bar is certainly seen in both Ornithomimidae and I-III extent of shaft-to-shaft contact 60-70% of Alvarezsauridae, but Suzuki et al . (2002) pointed out shafts ; metacarpal I length at least 60% that of that this feature is more widely distributed in metacarapal II). Ornithomimosaurs have paired Coelurosauria such as troodontids. They also flexor processes in manual proximal phalanges discussed that some characters are misinterpreted as suggested by Sereno (2001). In Pelecanimimus, by Sereno. Prefrontal exposure on the skull roof is the posteriormost tooth of maxillary teeth is

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A B C D E

I

I I I III II III II III II III II II III I

Fig. 3. Left metacarpals of ornithomimosaurs ; Harpymimus okladnikovi (A), Archaeornithomimus asiaticus (B), Sinornithomimus dongi (C), Struthiomimus altus (D), and Ornithomimus edmontonicus (E).

positioned anterior to posteriormost dentary tooth as matrix of Sereno (1999), Ornithomimidae from the seen in Shuvuuia (Sereno, 2001). Other toothed forms original matrix is replaced with eleven individual (Harpymimus and Shenzhousaurus) lack maxillary teeth ornithomimosaur taxa, producing a new data matrix and have dentery teeth at the anterior end of the with 27 ingroups. This analysis produced 290,382 lower jaw (Barsbold and Perle, 1984 ; Ji et al ., 2003 ; most parsimonious trees. Kobayashi and Barsbold, 2005). The other two A strict consensus tree shows an unresolved characters proposed by Sereno are not true for all polytomy of Alvarezsauridae and all member of ornithomimosaurs. The attachment of metacarpals II Ornithomimosauria, caused by three alternative and III is small (roughly 20% of metacarpal II placements of Pelecanimimus polyodon (Fig. 4). length), and that of metacarpals I and II vary among Pelecanimimus is shown as a sister taxon to the other taxa (Fig. 3). Primitive forms tend to have shorter members of Ornithomimosauria, in a position as a concatct between metacarpals I and II (50% or less). derived ornithomimosaur with Harpymimus okladnikovi Re-description of Harpymimus okladnikovi by Kobayashi and a Mongolian taxon (GIN 960910 KD) (Fig. 4 C), and Barsbold (2005) shows that metacarpal I is and a sister taxon to Alvarezsauridae (Fig. 4B and roughly half of metacarpal II. Re-evaluation of D), which is probably caused by the large amount of Sereno’s study (2001) by Suzuki et al . (2002) and this missing data for Pelecanimimus polyodon (89% is study infer that the affinities between Ornithomimidae missing). The monophyly of all ornithomimosaurs is and Alvarezsauridae are weaker than Sereno supported in the first and second alternative indicated. positions of Pelecanimimus polyodon and is supported by one unambiguous character (sub-equal metacarpals I Additional phylogenetic approach to test the preferable and II) in the first alternative, and by one unambiguous phylogenetic status of Ornithomimosauria character (absence of dentary teeth) in the second Among previous phylogenetic analyses of alternative placement. One unambiguous synapomorphy or Coelurosauria, such as Holtz (1998), unites Pelecanimimus polyodon and Alvarezsauridae Sereno (1999), Maryanska et al. (2002), and the (posteriormost maxillary tooth is anterior to Theropod Working Group, only the Theropod posteriormost dentary tooth) because the maxillary Working Group utilized specific-level terminal taxa, teeth are present only in Pelecanimimus polyodon whereas the other analyses, including Sereno (1999), among ornithomimosaurs. With or without inclusion used Ornithomimosauria or Ornithomimidae as a of Pelecanimimus polyodon in a monophyly of terminal taxon. Kobayashi (2004) demonstrated ornithomimosaurs, Harpymimus okladnikovi phylogenetic analyses on coelurosaurs using and GIN 960910KD (both are from Lower specific-level terminal taxa for Ornithomimosauria Cretaceous sediments) are more derived in based on data matrices of these previous studies. their phylogenetic positions than For a phylogenetic analysis based on the data forms (Fig. 4B-D). This result is discordant with

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Therizinosauridae B Alvarezsauridae Herrerasauridae Pelecanimimus* Ceratosauria Garudimimus* Anserimimus Torvosauridae Ornithomimus A Spinosauridae Struthiomimus Allosauridae Archaeornithomimus Gallimimus Sinraptoridae Dromiceiomimus Compsognathidae Sinornithomimus Huren-duh taxon* Ornitholestes Harpymimus* Deltadromeus Alvarezsauridae Pelecanimimus Therizinosauridae C Alvarezsauridae Harpymimus Garudimimus* Huren-duh taxon Anserimimus Ornithomimus Garudimimus Struthiomimus Archaeornithomimus Archaeornithomimus Sinornithomimus Gallimimus Dromiceiomimus Anserimimus Sinornithomimus Gallimimus Huren-duh taxon* Harpymimus* Ornithomimus Pelecanimimus* Dromiceiomimus Struthiomimus Therizinosauridae Therizinosauridae D Alvarezsauridae Pelecanimimus* Tyrannosauroidea Garudimimus* Caudipteryx Anserimimus Ornithomimus Caenagnathidae Struthiomimus Oviraptoridae Gallimimus Troodontidae Dromiceiomimus Sinornithomimus Dromaeosauridae Archaeornithomimus Aves Huren-duh taxon* Harpymimus*

Fig. 4. A strict consensus tree of 290,382 most parsimonious trees from the phylogenetic analysis based on data matrix by Kobayashi (2004), modified from Sereno (1999) (A) ; three possible placements of Pelecanimimus in most parsimonious trees (B-D).

previous studies and the temporal occurrences of pointing out some interpretations by Sereno ornithomimosaurs, indicating that the close relationship were unlikely and a phylogenetic analysis of Ornithomimidae and Alvarezsauridae may be suggests that the monophyly of Ornithomimidae supported by derived conditions in Ornithomimidae. and Alvarezsauridae is probably cased by derived This indicates that Sereno’sdata matrix may not be characters, at least, of ornithomimids. useful for resolving ornithomimosaur relationships in Coelurosauria. Acknowledgments I would like to thank Ren Hirayama (Waseda Conclusions University) to invide me to a symposium in 2008, Sereno (1999) suggested that the affinities organized by the Fossil Rerearch Society of Japan. I between ornithomimosaurs and alvarezsaurids would like to thank Louis L. Jacobs (Southern and bird-like features in both groups, forming Methodist University), Dale A. Winkler (Southern a monophyletic group. However, many of putative Methodist University), Anthony R. Fiorillo (Dallas synapomorphies for the clade, proposed by Sereno, Museum of Natural History), Philip J. Currie were evaluated by Suzuki et al. (2002) and they (University of ), and suggested that most were misinterpreted. This (Mongolian Academy of Sciences) for their advice study also supports Suzuki et al.’s study by and suggestions. I am grateful to Philip J. Currie,

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Mark A. Norell (American Museum of Natural Hwang, S. H., Norell, M. A., Ji, Q. and Gao, K. (2002) History), Peter J. Makovicky (Field Museum of New specimens of Microraptor zhaoianus (Theropoda : Natural History), Bernardino P. P!rez-Moreno Dromaeosauridae) from Northeastern China. (Universidad Auton"ma de Madrid), Zhi-Ming American Museum Novitates 3381, 1-44. Dong (Institute of and Ji,Q.,Norell,M.A.,Makovicky,P.J.,Gao,K.,Ji,S. Paleoanthropology), Kevin Seymour (Royal Ontario and Yuan, C. (2003) An early and Museum), Isao Takahashi (Gobi Support Japan), and implication for ornithomimosaur phylogeny. Kazuhisa Sato (Kanna Dinosaur Center) for providing American Museum Novitates 3420, 1-19. access to specimens. Kobayashi, Y. (2004) Asian ornithomimosaurs. Dedman College, Southern Methodist Univeristy, 1 References -340 [Ph.D. dissertation]. Barsbold, R. (1976) On the evolution and systematics Kobayashi, Y, and Lu, J.-C. (2003) A new ornithomimid of the late dinosaurs. In : Kramarenko, dinosaur with gregarious habits from the Late N. N. (ed) Paleontologiâ i biostratigrafiâ Mongolii, Cretaceous of China. Acta Palaeontologica Polonica pp. 68-75, Sovmestnaâ Svetsko-Mongolskaâ 48, 235-259. Paleontologiceskaâ Ekspediciâ, Trudy 3 : 3. Kobayashi, Y. and Barsbold, R. (2004) Phylogeny of Barsbold, R. (1981) Toothless carnivorous dinosaurs Ornithomimosauria and its paleobiogeographic of Mongolia. Transactions, Joint Soviet-Mongolian implications. Proceedings of the XIXth International Palaeontological Expedition 15, 28-39. Congress of Zoology, China, 50-52. Barsbold, R. and Osm"lska, H. (1990) Ornithomimosauria. Kobayashi, Y. and Barsbold, R. (2005) Anatomy of In : Weishampel, D. B., Dodson, P. and Osm"lska, Harpymimus okladnikovi Barsbold and Perle, 1984 H. (eds) The Dinosauria, pp. 225-244, University of (Dinosauria ; Theropoda) of Mongolia. In : Carpenter, California Press, Berkeley. K. (ed) Carnivorous Dinosaurs, pp.97-126, Bloomington, Barsbold, R. and Perle, A. (1984) On first new find of Indiana University Press. a primitive ornithomimosaur from the Cretaceous Makovicky P. J., Apesteguia, S. and Agnolin, F. L. of the MPR. Paleontologicheskiy Zhurnal, 121-123. (2005) The earliest dromaeosaurid theropod from Chiappe L. M., Norell, M. A. and Clark, J. M. (1996) South America. Nature 437, 1007-1011. Phylogenetic position of Mononykus (Aves: Makovicky, P. J., Kobayashi, Y. and Currie, P. J. Alvarezsauridae) from the Late Cretaceous of the (2004) Ornithomimosauria. In : D. B. Weishampel, . Memoirs of Queensland Museum 39, 557 Dodson,P.andOsm"lska,H.(eds)The Dinosauria, -582. 2nd edition, pp. 137-150, University of California Clark, J. M., Norell, M. A. and Makovicky, P. J. (2002) Press, Berkeley. Cladistic approaches to the relationships of birds Marsh, O. C. (1890) Description of new dinosaurian to other theropod dinosaurs ; In : Chiappe, L. M. reptiles. The American Journal of Science, Third Series and Witmer, L. M. (eds), Mesozoic Birds : Above the 39, 81-86. Heads of Dinosaurs, pp. 31-61, University of Maryanska, T., Osm"lska,H.andWolsan,M. California Press, Berkeley. (2002) Avialan status for Oviraptorosauria. Forster, C. A., Sampson, S. D., Chiappe, L. M. and Acta Palaeontologica Polonica 47, 97-116. Krause, D. W. (1998) The theropod ancestry of Norell, M. A., Clark, J. M. and Makovicky, P. J. (2002) birds : new evidence from the Late Cretaceous of Phylogenetic relationships among coelurosaurian Madagascar. Science 279, 1915-1919. theropods. In : Gauthier, J. and Gall, L. F. (eds) New Holtz, T. R., Jr. (1994) The phylogenetic position of Perspectives on the Origin and Early Evolution of the Tyrannosauridae: implications for theropod Birds : Proceedings of the International Symposium systematics. Journal of Paleontology 68, 1100-1117. in Honor of John H. Ostrom, pp. 49-67, Peabody Holtz, T. R., Jr. (1998) A new phylogeny of the Museum of Natural History, Yale University, New carnivorous dinosaurs. In : P!rez-Moreno, B. P., Haven. Holtz,T.Jr.,Sanz,J.L.andMoratalla,J.(eds) NorellM.A.,Clark,J.M.,Turner,A.H.,Makovicky, Aspects of Theropod Paleobiology, pp. 5-61, GAIA 15. P. J., Barsbold, R. and Rowe, T. (2006) A new

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