Journal of Mammalian Evolution

, Volume 17, Issue 3, pp 151–176 | Cite as

The Phylogenetic Relationships of Eucynodontia (Amniota: Synapsida)

  • Jun Liu
  • Paul Olsen
Original Paper


The phylogeny of Eucynodontia is an important topic in vertebrate paleontology and is the foundation for understanding the origin of mammals. However, consensus on the phylogeny of Eucynodontia remains elusive. To clarify their interrelationships, a cladistic analysis, based on 145 characters and 31 species, and intergrating most prior works, was performed. The monophyly of Eucynodontia is confirmed, although the results slightly differ from those of previous analyses with respect to the composition of both Cynognathia and Probainognathia. This is also the first numerical cladistic analysis to recover a monophyletic Traversodontidae. Brasilodon is the plesiomorphic sister taxon of Mammalia, although it is younger than the oldest mammals and is specialized in some characters. A monophyletic Prozostrodontia, including tritheledontids, tritylodontids, and mammals, is well supported by many characters. Pruning highly incomplete taxa generally has little effect on the inferred pattern of relationships among the more complete taxa, although exceptions sometimes occur when basal fragmentary taxa are removed. Taxon sampling of the current data matrix shows that taxon sampling was poor in some previous studies, implying that their results are not reliable. Two major unresolved questions in cynodont phylogenetics are whether tritylodontids are more closely related to mammals or to traversodontids, and whether tritylodontids or tritheledontids are closer to mammals. Analyses of possible synapomorphies support a relatively close relationship between mammals and tritylodontids, to the exclusion of traversodontids, but do not clearly indicate whether or not tritheledontids are closer to mammals than are tritylodontids.


Phylogeny Eucynodontia Tritheledontidae Tritylodontidae Traversodontidae Mammal 



We thank James Hopson, Hans-Dieter Sues, Marina Bento Soares, and especially Fernando Abdala for fruitful discussions. The comments from Zhe-Xi Luo, Fernando Abdala, Agustín G. Martinelli, and John R. Wible greatly improved this paper. The cooperation and hospitality of the staff of various museums and institutions greatly facilitated our comparative studies. We would like to thank Tom Kemp (Oxford University Museum of Natural History, UK); Ray Symonds (University Museum of Zoology, Cambridge, UK); Sandra Chapman (Natural History Museum, London, UK); Fernando Abdala and Bruce Rubidge (Bernard Price Institute for Palaeontological Research, Johannesburg, South Africa); Jennifer Botha and Elize Butler (National Museum, Bloemfontein, South Africa); Roger Smith and Sheena Kaal (Iziko Museums–South African Museum, Cape Town, South Africa); Johann Neveling (Council for Geosciences, Pretoria, South Africa); Stephany Potze (Transvaal Museum, South Africa); Ana Maria Ribeiro (Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul, Porto Alegre, Brazil); Maria C. Malabarba (Museu de Ciências e Tecnologia, Pontifïcia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil); Marina B. Soares and Cesar L. Schultz (Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil); Jaime E. Powell (Universidad Nacional de Tucumán, Argentina); Alejandro Kramarz and Agustín G. Martinelli (Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Buenos Aires, Argentina); Guillermo F. Vega (Museo de Antropología, Universidad Nacional de La Rioja, Argentina); Ricardo Martinez (Museo de Ciencias Naturales, Universidad Nacional de San Juan, Argentina); Marcelo Reguero and Rosendo Pascual (Museo de La Plata, Argentina); Charles R. Schaff and Wu Shaoyuan (Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA), Hans-Dieter Sues and Matthew Carrano (National Museum of Natural History, Washington, D.C., USA), James A. Hopson (University of Chicago, Chicago, USA), Olivier Rieppel, Elaine Zeiger, and William F. Simpson (Field Museum of Natural History, Chicago, USA); and John Flynn (American Museum of Natural History, New York, USA). Special thanks to Corwin Sullivian for reading the manuscript and greatly improving the writing.

Financial support for this project was provided by Columbia University through a Faculty Fellowship, the Climate Center of Lamont-Dohert Earth Observatory, Theodore Roosevelt Memorial Fund of AMNH, and Chinese Academy of Sciences (KZCX2-YW-BR-07). The Field Museum provided grants that make possible a study visit to Chicago.


  1. Abdala F (2007) Redescription of Platycraniellus elegans (Therapsida, Cynodontia) from the Early Triassic of South Africa, and the cladistic relationships of eutheriodonts. Palaeontology 50:591–618CrossRefGoogle Scholar
  2. Abdala F, Giannini NP (2002) Chiniquodontid cynodonts: systematic and morphometric considerations. Palaeontology 45:1151–1170CrossRefGoogle Scholar
  3. Abdala F, Ribeiro AM (2003) A new traversodontid cynodont from the Santa Maria Formation (Ladinian–Carnian) of southern Brazil, with a phylogenetic analysis of Gondwanan traversodontids. Zool J Linn Soc 139:529–545CrossRefGoogle Scholar
  4. Allin EF, Hopson JA (1992) Evolution of the auditory system in Synapsida (“mammal-like reptiles” and primitive mammals) as seen in the fossil record. In: Webster DB, Fay RR, Popper AN (eds) The Evolutionary Biology of Hearing. Springer-Verlag, New York, pp 587–614Google Scholar
  5. Barghusen HR, Hopson JA (1970) Dentary-squamosal joint and the origin of mammals. Science 168:573–575CrossRefPubMedGoogle Scholar
  6. Battail B (1991) Les Cynodontes (Reptilia, Therapsida); une phylogenie. Bull Mus Natl Hist Nat, Sect C, Sci terre paléontol géol minér 13:17–105Google Scholar
  7. Bonaparte JF (1963) Descripción del esqueleto postcraneano de Exaeretodon (Cynodontia-Traversodontidae). Acta Geol Lilloana 4:5–52Google Scholar
  8. Bonaparte JF (1966) Sobre las cavidades cerebral, nasal y otras estructuras del cráneo de Exaeretodon sp (Cynodontia, Traversodontidae). Acta Geol Lilloana 8:5–31Google Scholar
  9. Bonaparte JF, Barberena MC (2001) On two advanced carnivorous cynodonts from the Late Triassic of southern Brazil. Bull Mus Comp Zool 156:59–80Google Scholar
  10. Bonaparte JF, Martinelli AG, Schultz CL (2005) New information on Brasilodon and Brasilitherium (Cynodontia, Probainognathia) from the Late Triassic, southern Brazil. Rev Bras Paleontol 8:25–46CrossRefGoogle Scholar
  11. Bonaparte JF, Martinelli AG, Schultz CL, Rubert R (2003) The sister group of mammals: small cynodonts from the late Triassic of southern Brazil. Rev Bras Paleontol 5:5–27Google Scholar
  12. Brink AS (1988) Illustrated bibliographical catalogue of the Synapsida, Part 2. Handbook S Afr Geol SurvGoogle Scholar
  13. Broom R (1912) On a new type of cynodont from the Stormberg. Ann S Afr Mus 7:334–336Google Scholar
  14. Crompton AW (1964) On the skull of Oligokyphus. Bull Brit Mus (Nat Hist) Geol 9:67–81Google Scholar
  15. Crompton AW (1972) Postcanine occlusion in cynodonts and tritylodontids. Bull Brit Mus (Nat Hist) Geol 21:29–71Google Scholar
  16. Crompton AW, Ellenberger F (1957) On a new cynodont from the Molteno Beds and the origin of the tritylodontids. Ann S Afr Mus 44:1–13Google Scholar
  17. Crompton AW, Jenkins FA Jr (1979) Origin of mammals. In: Lillegraven JA, Kielan-Jaworowska Z, Clemens WA (eds) Mesozoic Mammals: the First Two-Thirds of Mammalian History. University of California Press, Berkeley, pp 59–73Google Scholar
  18. Crompton AW, Luo Z-X (1993) Relationships of the Liassic mammals Sinoconodon, Morganucodon oehleri, and Dinnetherium. In: Szalay FS, Novacek MJ, McKenna MC (eds) Mammal Phylogeny: Mesozoic Differentiation, Multituberculates, Monotremes, Early Therians, and Marsupials. Springer-Verlag, New York, pp 30–44Google Scholar
  19. Cui G-H, Sun A-L (1987) Postcanine root-system in tritylodonts. Vertebr Palasiatica 25:245–259Google Scholar
  20. Datta PM, Das DP, Luo Z-X (2004) A Late Triassic dromatheriid (Synapsida: Cynodontia) from India. Ann Carnegie Mus 73:72–84Google Scholar
  21. Debry R (2005) The systematic component of phylogenetic error as a function of taxonomic sampling under parsimony. Syst Biol 54:432–440CrossRefPubMedGoogle Scholar
  22. Donoghue MJ (1994) Progress and prospects in reconstructing plant phylogeny. Ann Mo Bot Gard 81:405–418CrossRefGoogle Scholar
  23. Fourie S (1974) The cranial morphology of Thrinaxodon liorhinus Seeley. Ann S Afr Mus 46:337–400Google Scholar
  24. Gauthier J (1986) Saurischian monophyly and the origin of birds. Mem Cal Acad Sci 8:1–55Google Scholar
  25. Gow CE (1980) The dentitions of the Tritheledontidae (Therapsida, Cynodontia). Proc Roy Soc London B 208:461–481CrossRefGoogle Scholar
  26. Gow CE (1981) Pachygenelus, Diarthrognathus and the double jaw articulation. Palaeontol Afr 24:15Google Scholar
  27. Gow CE (1986) A new skull of Megazostrodon (Mammalia: Triconodonta) from the Elliot Formation (Lowe Jurassic) of southern Africa. Palaeontol Afr 26:13–23Google Scholar
  28. Gow CE (1994) New find of Diarthrognathus (Therapsida: Cynodontia) after seventy years. Palaeontol Afr 31:51–54Google Scholar
  29. Hahn G, Hahn R, Godefroit P (1994) Zur Stellung der Dromatheriidae (Ober–Trias) zwischen den Cynodontia und den Mammalia. Geol Palaeontol 28:141–159Google Scholar
  30. Hahn G, Lepage JC, Wouters G (1984) Cynodontier–Zaehne aus der ober–Trias von Medernach, Grossherzoghum Luxemburg. Bull Soc Belg Géol 93:357–373Google Scholar
  31. Haughton SH, Brink AS (1954) A bibliographic list of the Reptilia from the Karoo beds of Africa. Palaeontol Afr 2:1–187Google Scholar
  32. Hauser DL, Presch W (1991) The effect of ordered characters on phylogenetic reconstruction. Cladistics 7:243–265CrossRefGoogle Scholar
  33. Hopson JA (1964) The braincase of the advanced mammal-like reptile Bienotherium. Postilla 87:1–30Google Scholar
  34. Hopson JA (1969) The origin and adaptive radiation of mammal-like reptiles and nontherian mammals. Ann NY Acad Sci 167:199–216CrossRefGoogle Scholar
  35. Hopson JA (1985) Morphology and relationships of Gomphodontosuchus brasiliensis von Huene (Synapsida, Cynodontia, Tritylodontoidea) from the Triassic of Brazil. Neues Jahrb Geol Paläontol Monatsh 1985(5):285–299Google Scholar
  36. Hopson JA (1991) Systematics of the non-mammalian Synapsida and implications for patterns of evolution in Synapsida. In: Schultze H-P, Trueb L (eds) Origins of the Higher Groups of Tetrapods: Controversy and Consensus. Cornell University Press, Ithaca and London, pp 635–693Google Scholar
  37. Hopson JA (1994) Synapsid evolution and the radiation of non-eutherian mammals. In: Prothero DR, Schoch RM (eds) Major Features of Vertebrate Evolution. The University of Tennessee Press, Knoxville, pp 190–219Google Scholar
  38. Hopson JA (2005) A juvenile gomphodont cynodont specimen from the Cynognathus Assemblage Zone of South Africa: implications for the origin of gomphodont postcanine morphology. Palaeontol Afr 41:53–66Google Scholar
  39. Hopson JA, Barghusen HR (1986) An analysis of therapsid relationships. In: Hotton N III, MacLean PD, Roth JJ, Roth EC (eds) The Ecology and Biology of Mammal-like Reptiles. Smithsonian Institution Press, Washington D.C., pp 83–106Google Scholar
  40. Hopson JA, Crompton AW (1969) Origin of mammals. In: Dobzhansky T, Hecht MK, Steere WC (eds) Evolutionary Biology, Vol. 3. Appleton-Century-Crofts, New York, pp 15–72Google Scholar
  41. Hopson JA, Kitching JW (1972) A revised classification of cynodonts (Reptilia; Therapsida). Palaeontol Afr 14:71–85Google Scholar
  42. Hopson JA, Kitching JW (2001) A probainognathian cynodont from South Africa and the phylogeny of non-mammalian cynodonts. Bull Mus Comp Zool 156:5–35Google Scholar
  43. Jenkins FA Jr, Parrington FR (1976) The postcranial skeleton of the Triassic mammals Eozostrodon, Megazostrodon and Erythrotherium. Phil Trans Roy Soc Lond B 273:387–431CrossRefGoogle Scholar
  44. Kamiya H, Yoshida T, Kusuhashi N, Matsuoka H (2006) Enamel texture of the tritylodontid mammal-like reptile, occurred from the lower Cretaceous in central Japan. Materials Sci Engin C 26:707–709CrossRefGoogle Scholar
  45. Kearney M, Clark JM (2003) Problems due to missing data in phylogenetic analyses including fossils: a critical review. J Vertebr Paleontol 23:263–274CrossRefGoogle Scholar
  46. Kemp TS (1982) Mammal-like Reptiles and the Origin of Mammals. Academic Press, London and New YorkGoogle Scholar
  47. Kemp TS (1983) The relationships of mammals. Zool J Linn Soc 77:353–384CrossRefGoogle Scholar
  48. Kemp TS (2005) The Origin and Evolution of Mammals. Oxford University Press, OxfordGoogle Scholar
  49. Kemp TS (2007) The concept of correlated progression as the basis of a model for the evolutionary origin of major new taxa. Proc Roy Soc B 274:1667–1673CrossRefGoogle Scholar
  50. Kühne WG (1956) The Liassic therapsid Oligokyphus. British Museum (Natural History), LondonGoogle Scholar
  51. Lucas SG, Hunt AP (1994) The chronology and paleobiogeography of mammalian origins. In: Fraser NC, Sues H-D (eds) In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods. Cambridge University Press, Cambridge, New York, pp 335–351Google Scholar
  52. Lucas SG, Luo Z-X (1993) Adelobasileus from the Upper Triassic of West Texas; the oldest mammal. J Vertebr Paleontol 13:309–334Google Scholar
  53. Luo Z-X (1994) Sister-group relationships of mammals and transformations of diagnostic mammalian characters. In: Fraser NC, Sues H-D (eds) In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods. Cambridge University Press, Cambridge, New York, pp 98–128Google Scholar
  54. Luo Z-X (2001) The inner ear and its bony housing in tritylodontids and implications for evolution of the mammalian ear. Bull Mus Comp Zool 156:81–97Google Scholar
  55. Luo Z-X (2007) Transformation and diversification in early mammal evolution. Nature 450:1011–1019CrossRefPubMedGoogle Scholar
  56. Luo Z-X, Crompton AW (1994) Transformation of the quadrate (incus) through the transition from non-mammalian cynodonts to mammals. J Vertebr Paleontol 14:341–374Google Scholar
  57. Luo Z-X, Crompton AW, Sun A-L (2001) A new mammaliaform from the Early Jurassic and evolution of mammalian characteristics. Science 292:1535–1540CrossRefPubMedGoogle Scholar
  58. Luo Z-X, Kielan-Jaworowska Z, Cifelli RL (2002) In quest for a phylogeny of Mesozoic mammals. Acta Palaeontol Pol 47:1–78Google Scholar
  59. Maddison DR, Maddison WP (2005) MacClade 4: analysis of phylogeny and character evolution, version 4.08. Sinauer Associates, Sunderland, MassachusettsGoogle Scholar
  60. Martinelli AG, Bonaparte JF, Schultz CL, Rubert R (2005) A new tritheledontid (Therapsida, Eucynodontia) from the Late Triassic of Rio Grande do Sul (Brazil) and its phylogenetic relationships among carnivorous non-mammalian eucynodonts. Ameghiniana 42:191–208Google Scholar
  61. Martinelli AG, Rougier GW (2007) On Chaliminia musteloides (Eucynodontia: Tritheledontidae) from the Late Triassic of Argentina, and a phylogeny of Ictidosauria. J Vert Paleontol 27:442–460CrossRefGoogle Scholar
  62. Martinez RN, May CL, Forster CA (1996) A new carnivorous cynodont from the Ischigualasto Formation (Late Triassic, Argentina), with comments on eucynodont phylogeny. J Vertebr Paleontol 16:271–284Google Scholar
  63. Olson EC (1944) Origin of mammals based upon cranial morphology of the therapsid suborders. Spec Papers, Geol Soc Amer 55:1–136Google Scholar
  64. Olson EC (1959) The evolution of mammalian characters. Evolution 13:44–353CrossRefGoogle Scholar
  65. Osborn HF (1886) Observations on the Upper Triassic mammals, Dromatherium and Microconodon. Proc Acad Nat Sci Philadelphia 37:359–363Google Scholar
  66. Osborn HF (1887) The Triassic mammals, Dromatherium and Microconodon. Proc Am Phil Soc 24:109–111Google Scholar
  67. Owen R (1871) Monograph of the Fossil Mammalia from the Mesozoic Formations. Paleontographical Society, LondonGoogle Scholar
  68. Pollock DD, Zwickl DJ, McGuire JA, Hillis DM (2002) Increased taxon sampling is advantageous for phylogenetic inference. Syst Biol 51:664–671CrossRefPubMedGoogle Scholar
  69. Prendini L (2001) Species or supraspecific taxa as terminals in cladistic analysis? Groundplans versus exemplars revisited. Syst Biol 50:290–300CrossRefPubMedGoogle Scholar
  70. Rice KA, Donoghue MJ, Olmstead RG (1997) Analyzing large data sets: rbcL 500 revisited. Syst Biol 46:554–563PubMedGoogle Scholar
  71. Romer AS (1970) The Chanares (Argentina) Triassic reptile fauna VI: A chiniquodontid cynodont with an incipient squamosal-dentary jaw articulation. Breviora 344:1–18Google Scholar
  72. Rougier GW, Wible JR, Hopson JA (1992) Reconstruction of the cranial vessels in the Early Cretaceous mammal Vincelestes neuquenianus: implications for the evolution of the mammalian cranial vascular system. J Vertebr Paleontol 12:188–216Google Scholar
  73. Rowe T (1986) Osteological diagnosis of Mammalia, L. 1758, and its relationship to extinct Synapsida. PhD thesis, University of California, BerkeleyGoogle Scholar
  74. Rowe T (1988) Definition, diagnosis and origin of Mammalia. J Vertebr Paleontol 8:241–264Google Scholar
  75. Rowe T (1993) Phylogenetic systematics and the early history of mammals. In: Szalay FS, Novacek MJ, McKenna MC (eds) Mammal Phylogeny: Mesozoic Differentiation, Multituberculates, Monotremes, Early Therians, and Marsupials. Springer-Verlag, New York, pp 129–145Google Scholar
  76. Seeley HG (1895) Researches on the structure, organization, and classification of the fossil Reptilia. Part IX, section 4. On the Gomphodontia. Phil Trans R Soc Lond B 186:1–57CrossRefGoogle Scholar
  77. Shubin NH, Crompton AW, Sues HD, Olsen PE (1991) New fossil evidence on the sister-group of mammals and early Mesozoic faunal distributions. Science 251:1063–1065CrossRefPubMedGoogle Scholar
  78. Sidor CA, Hancox PJ (2006) Elliotherium kersteni, a new tritheledontid from the Lower Elliot Formation (Upper Triassic) of South Africa. J Paleont 80:333–342CrossRefGoogle Scholar
  79. Sidor CA, Smith RM (2004) A new galesaurid (Therapsida: Cynodontia) from the Lower Triassic of South Africa. Palaeontology 47:535–556CrossRefGoogle Scholar
  80. Simpson GG (1926a) Are Dromatherium and Microconodon mammals? Science 63:548–549CrossRefPubMedGoogle Scholar
  81. Simpson GG (1926b) Mesozoic Mammalia. V. Dromatherium and Microconodon. Am J Sci 12:87–108Google Scholar
  82. Simpson GG (1928) A Catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum. Trustees of the British Museum, LondonGoogle Scholar
  83. Simpson GG (1929) American Mesozoic Mammalia. Mem Peabody Mus, Yale Univ 3:1–235Google Scholar
  84. Slowinski JB (1993) “Unordered” versus “ordered” characters. Syst Biol 42:155–165Google Scholar
  85. Soares MB (2004) Novos materiais de Riograndia guaibaensis (Cynodontia, Tritheledontidae) do Triásico Superior do Rio Grande do Sul, Brasil: analise osteológica e implicaçōes filogenéticas. Ph.D Thesis, Universidade Federal do Rio Grande do Sul, Rio Grande do SulGoogle Scholar
  86. Strong EE, Lipscomb D (1999) Character coding and inapplicable data. Cladistics 15:363–371CrossRefGoogle Scholar
  87. Sues H-D (1985) The relationships of the Tritylodontidae (Synapsida). Zool J Linn Soc 85:205–217CrossRefGoogle Scholar
  88. Sues H-D (1986) The skull and dentition of two tritylodontid synapsids from the Lower Jurassic of western North America. Bull Mus Comp Zool 151:217–268Google Scholar
  89. Sues H-D (2001) On Microconodon, a Late Triassic cynodont from the Newark Supergroup of eastern North America. Bull Mus Comp Zool 156:37–48Google Scholar
  90. Sues H-D, Jenkins FA Jr (2006) The postcranial skeleton of Kayentatherium wellesi from the Lower Jurassic Kayenta Formation of Arizona and the phylogenetic significance of postcranial features in tritylodontid cynodonts. In: Carrano MT, Blob RW, Gaudin TJ, Wible JR (eds) Amniote Paleobiology: Perspectives on the Evolution of Mammals, Birds, and Reptiles. The University of Chicago Press, Chicago, pp 114–152Google Scholar
  91. Sun A-L (1984) Skull morphology of the tritylodont genus Bienotheroides of Sichuan. Sci Sin, Ser B 27:970–984Google Scholar
  92. Watson DMS (1942) On Permian and Triassic tetrapods. Geol Mag 79:81–116CrossRefGoogle Scholar
  93. Wible JR (1991) Origin of Mammalia: the craniodental evidence reexamined. J Vertebr Paleontol 11:1–28Google Scholar
  94. Wible JR, Hopson JA (1993) Basicranial evidence for early mammal phylogeny. In: Szalay FS, Novacek MJ, McKenna MC (eds) Mammal Phylogeny: Mesozoic Differentiation, Multituberculates, Monotremes, Early Therians, and Marsupials. Springer-Verlag, New York, pp 45–62Google Scholar
  95. Wible JR, Hopson JA (1995) Homologies of the prootic canal in mammals and non-mammalian cynodonts. J Vertebr Paleontol 15:331–356Google Scholar
  96. Wiens JJ (1998) The accuracy of methods for coding and sampling higher-level taxa for phylogenetic analysis: a simulation study. Syst Biol 47:397–413CrossRefPubMedGoogle Scholar
  97. Wiens JJ (2003) Incomplete taxa, incomplete characters, and phylogenetic accuracy: is there a missing data problem? J Vertebr Paleontol 23:297–310Google Scholar
  98. Wiens JJ, Hollingsworth BD (2000) War of the iguanas: conflicting molecular and morphological phylogenies and long-branch attraction in iguanid lizards. Syst Biol 49:143–159CrossRefPubMedGoogle Scholar
  99. Wilkinson M (2003) Missing entries and multiple trees: instability, relationships, and support in parsimony analysis. J Vertebr Paleontol 23:311–323CrossRefGoogle Scholar
  100. Young CC (1947) Mammal-like reptiles from Lufeng, Yunnan, China. Proc Zool Soc Lond 117:537–597Google Scholar
  101. Zwickl DJ, Hillis DM (2002) Increased taxon sampling greatly reduces phylogenetic error. Syst Biol 51:588–598CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and PaleonanthropologyChinese Academy of SciencesBeijingChina
  2. 2.Lamont-Doherty Earth ObservatoryColumbia UniversityPalisadesUSA

Personalised recommendations