Re-examination of the Jurassic Mammaliaform Docodon victor by Computed Tomography and Occlusal Functional Analysis

  • Julia A. Schultz
  • Bhart-Anjan S. Bhullar
  • Zhe-Xi Luo
Original Paper


Docodon was the first described docodont, and has long featured prominently in the comparative and functional morphology of mammaliaform mandibles and teeth. We have now re-examined the dental and mandibular fossils of Docodon from Yale Quarry 9 at the Como Bluff site in the Late Jurassic Morrison Formation, using Computed Tomography (CT) scans and 3D image analyses. Our CT study revealed that some features used to distinguish the several Docodon “species” in historical studies many decades ago were based on incorrect manual restoration of mandibles, and on variable features of deciduous premolars, which are replaced in typical mammaliaform fashion. This supports a long-held notion that the multiple species of Docodon from the same quarry of the Morrison Formation are over-split and should be synonymized. We formally propose that the specimens examined in this study be synonymized under Docodon victor. Our new Occlusal Fingerprint Analysis (OFA) of Docodon molars supports the hypothesis that Docodon had a consistent dorso-posterior or palinal component in chewing in the disto-distolingual to distolingual direction. This helps to resolve the controversial historical alternative hypotheses postulated for tooth occlusion in the taxon. The Docodon occlusal pattern is likely a derived feature, evolved within Docodonta. A posterior component in the occlusal trajectory is a functional convergence of Docodon on unrelated traversodontid cynodonts.


Docodon Mammaliaformes Jurassic CT reconstruction Tooth function 



We are indebted to Professor Jacques A. Gauthier, Dr. Daniel Brinkman, and Marilyn Fox of Yale Peabody Museum of Natural History for their support of, and much logistic help with this study. We would also like to thank April I. Neander for her assistance in some of the CT rendering and graphics. During this study, we benefited from extensive discussion with Profs. Callum Ross (UChicago), Thomas Martin (Uni-Bonn), David Strait (Washington University), Guillermo Rougier and Brian Davis (University of Louisville), Dr. Amanda Smith (Washington University), and David Grossnickle (UChicago). We also benefited from access to comparative collections in University of Bonn (Prof. Thomas Martin and Janka Brinkkötter), Beijing Museum of Natural History (Prof. Qing-Jin Meng and Di Liu). This manuscript also benefited from suggestions for improvement from Dr. John R. Wible, an anonymous referee and Dr. Alexander Averianov. Financial support for this work is from DAAD (Deutscher Akademischer Austauschdienst) (J. A. Schultz), funding from Yale University (B.-A. S. Bhullar), and the University of Chicago (B.-A. S. Bhullar and Z.-X. Luo).

Supplementary material

10914_2017_9418_MOESM1_ESM.mp4 (17.1 mb)
ESM 1 Supplementary Information Video S1. Forensic analysis and virtual correction of the manual preparation errors in Docodon mandible by history studies of Marsh (1881 and 1887) that were wide circulated in subsequent comparative studies. X-axis, posterior; Y-axis, occlusal; Z-axis, posterior. (MP4 17,504 kb)
10914_2017_9418_MOESM2_ESM.mp4 (53.3 mb)
ESM 2 Supplementary Information Video S2. Occlusal Fingerprint Analysis re-enactment of the Jenkins (1969) hypothesis for proal-lingual chewing movement (Part 1), in comparison to the best-fit chewing trajectory and occlusal contacts by this study (Part 2) that corroborates the Gingerich (1973) interpretation for a palinal-distolingual chewing movement. Orientation of lower molars: X-axis, labial; Y-axis, mesial; Z-axis, occlusal. Lower molars m3-m5 based on YPM11826; upper molars M3-M4 based on YPM10647. (MP4 54,607 kb)
10914_2017_9418_MOESM3_ESM.stl (16.8 mb)
ESM 3 STereoLithography (STL) Files. STL’s of the lower jaw and upper and lower teeth Docodon victor: Composite dentary, upper molars, and lower molars. (STL 17189 kb)
10914_2017_9418_MOESM4_ESM.stl (8.7 mb)
ESM 4 (STL 8889 kb)
10914_2017_9418_MOESM5_ESM.stl (14.8 mb)
ESM 5 (STL 15157 kb)


  1. Abdala F, Jasinoski SC, Fernandez V (2013) Ontogeny of the Early Triassic cynodont Thrinaxodon liorhinus (Therapsida): dental morphology and replacement. J Vertebr Paleontol 33: 1408–1431. CrossRefGoogle Scholar
  2. Amano O, Doi T, Yamada T, Sasaki A, Sakiyama K, Kanegae H, Kindaichi K (2010) Meckel's cartilage: discovery, embryology and evolution: overview of the specificity of Meckel's cartilage. J Oral Biosci 52: 125–135Google Scholar
  3. Anthwal N, Joshi L, Tucker AS (2013) Evolution of the mammalian middle ear and jaw: adaptations and novel structures. J Anat 222:147–160CrossRefPubMedGoogle Scholar
  4. Anthwal N, Urban DJ, Luo Z-X, Sears KE, Tucker, AS (2017) Meckel's cartilage breakdown offers clues to mammalian middle ear evolution. Nature Ecology & Evolution 1: 0093. CrossRefGoogle Scholar
  5. Averianov AO (2004) Interpretation of the Early Cretaceous mammal Peraiocynodon (Docodonta) and taxonomyof some British Mesozoic docodonts. Russ J Theriol 3: 1–4CrossRefGoogle Scholar
  6. Averianov AO, Lopatin AV (2006) Itatodon tatarinovi (Tegotheriidae, Mammalia), a docodont from the Middle Jurassic of western Siberia and phylogenetic analysis of Docodonta. Paleontol J 40: 668–677CrossRefGoogle Scholar
  7. Averianov AO, Lopatin AV (2015) Mammal remains from the Lower Cretaceous Bol'shoi Terekhtyul' locality in west Siberia, Russia. Cretaceous Res 54: 14–53. CrossRefGoogle Scholar
  8. Averianov AO, Lopatin AV, Krasnolutskii, SA, Ivantsov SV (2010) New docodontans from the Middle Jurassic of Siberia and reanalysis of Docodonta interrelationships. Proc Zool Inst Russ Acad Sci 314: 121–148Google Scholar
  9. Barghusen HR (1968) The lower jaw of cynodonts (Reptilia, Therapsida) and the evolutionary origin of mammal-like adductor jaw musculature. Postilla 116: 1–49Google Scholar
  10. Benazzi S, Kullmer O, Grosse IR, Weber GW (2011). Using occlusal wear information and finite element analysis to investigate stress distributions in human molars. J Anat 219: 259–272CrossRefPubMedPubMedCentralGoogle Scholar
  11. Benazzi S, Kullmer O, Schulz D, Gruppioni G, Weber, GW (2013). Technical note: individual tooth macrowear pattern guides the reconstruction of the Sts 52 (Australopithecus africanus) dental arches. Am J Phys Anthropol 150: 324–329CrossRefPubMedGoogle Scholar
  12. Bi S-D, Wang Y-Q, Guan J, Sheng X, Meng J (2014) Three new Jurassic euharamiyidan species reinforce early divergence of mammals. Nature 514: 579–584CrossRefPubMedGoogle Scholar
  13. Butler PM (1939) The teeth of the Jurassic mammals. Proc Zool Soc Lond 109: 329–356Google Scholar
  14. Butler PM (1988) Docodont molars as tribosphenic analogues (Mammalia, Jurassic). In: Russell DE, Santoro J-P, Sigogneau-Russell D (eds) Teeth Revisited: Proceedings of the VIIth International Symposium on Dental Morphology. Mém Mus natl Hist nat C 53, pp 329–340Google Scholar
  15. Butler PM (1997) An alternative hypothesis on the origin of docodont molar teeth. J Vertebr Paleontol 17: 435–439.CrossRefGoogle Scholar
  16. Butler PM (2000) Review of the early allotherian mammals. Acta Palaeontol Pol 45: 317–342Google Scholar
  17. Crompton AW (1972) Postcanine occlusion in cynodonts and tritylodonts. Bull Brit Mus (Nat Hist) Geol 21: 30–71Google Scholar
  18. Crompton AW (2011) Masticatory motor programs in Australian herbivorous mammals: Diprotodontia. Integrat Comp Biol 51: 271–281. CrossRefGoogle Scholar
  19. Crompton AW, Hiiemae KM (1970) Molar occlusion and mandibular movements during occlusion in the American opossum, Didelphis marsupialis L. Zool J Linn Soc 49: 21–47CrossRefGoogle Scholar
  20. Crompton AW, Hylander WL (1986) Changes in mandibular function following the acquisition of a dentary-squamosal joint. In: Hotton N III, MacLean PD, Roth JJ, Roth EC (eds) The Ecology and Biology of Mammal-like Reptiles). Smithsonian Institution Press, Washington, pp 263–282Google Scholar
  21. Crompton AW, Jenkins FA Jr (1968) Molar occlusion in Late Triassic mammals. Biol Rev 43: 427–458CrossRefPubMedGoogle Scholar
  22. Crompton AW, Luo Z-X (1993) The relationships of the Liassic mammals Sinoconodon, Morganucodon oehleri and Dinnetherium. In: Szalay FS, Novacek MJ, McKenna MC (eds) Mammal Phylogeny. Vol.1. Mesozoic Differentiation, Multituberculates, Monotremes, Early Therians, and Marsupials. Springer-Verlag, New York, pp 30–44Google Scholar
  23. Davis BM (2011) A novel interpretation of the tribosphenidan mammal Slaughteria eruptens from the Lower Cretaceous Trinity Group, and implications for dental formula in early mammals. J Vertebr Paleontol 31: 676–683CrossRefGoogle Scholar
  24. Druzinsky RE, Doherty AH, De Vree FL (2011) Mammalian masticatory muscles: homology, nomenclature, and diversification. Integrat Comp Biol 51: 224–234. CrossRefGoogle Scholar
  25. Engelmann GF, Callison, G (1998) Mammalian faunas of the Morrison Formation. Modern Geol 23: 343–379Google Scholar
  26. Evans HE, de Lahunta A (2013) Miller’s Anatomy of the Dog (4th edition). Elsevier-Saunders, Saint Louis, 850 ppGoogle Scholar
  27. Evans AR, Sanson GD (2006) Spatial and functional modeling of carnivore and insectivore molariform teeth. J Morphol 267: 649–662CrossRefPubMedGoogle Scholar
  28. Foster J (2007) Jurassic West: Dinosaurs of the Morrison Formation and Their World. Indiana University Press, Bloomington, 416 ppGoogle Scholar
  29. Gill PG, Purnell MA, Crumpton N, Robson Brown K, Gostling NJ, Stampanon M, Rayfield EJ (2014) Dietary specializations and diversity in feeding ecology of the earliest stem mammals. Nature 512: 303–305CrossRefPubMedGoogle Scholar
  30. Gingerich PD (1973) Molar occlusion and function in the Jurassic mammal Docodon. J Mammal 254: 1008–1013CrossRefGoogle Scholar
  31. Greenwald NS (1988) Patterns of tooth eruption and replacement in multituberculate mammals. J Vertebr Paleontol 8: 265–277CrossRefGoogle Scholar
  32. Grossnickle DM (2017) The evolutionary origin of jaw yaw in mammals. Scientific Reports 7: 45094. CrossRefPubMedPubMedCentralGoogle Scholar
  33. Hopson JA, Crompton AW (1969) Origin of mammals. In: Dobzhansky T, Hecht MK, Steere WC (eds) Evolutionary Biology, Volume 3. Appleton-Century-Crofts, New York, pp 15–72Google Scholar
  34. Hu Y-M, Meng J, Clark JM (2007) A new Late Jurassic docodont (Mammalia) from northeastern Xinjiang, China. Vertebr PalAsiatica 45: 173–194Google Scholar
  35. Hylander WL, Wall CE, Vinyard CJ, Ross C, Ravosa MR, Williams SH, Johnson KR (2005) Temporalis function in anthropoids and strepsirrhines: an EMG study. Am J Phys Anthropol 128:35–56Google Scholar
  36. Ishizeki K, Saito H, Shinagawa T, Fujiwara N, Nawa T (1999) Histochemical and immunohistochemical analysis of the mechanism of calcification of Meckel's cartilage during mandible development in rodents. J Anat 194: 265–277CrossRefPubMedPubMedCentralGoogle Scholar
  37. Ishizeki K, Takahashi N, Nawa T (2001) Formation of the sphenomandibular ligament by Meckel’s cartilage in the mouse: possible involvement of epidermal growth factor as revealed by studies in vivo and in vitro. Cell Tissue Res 304: 67–80CrossRefPubMedGoogle Scholar
  38. Jenkins FA Jr (1969) Occlusion in Docodon (Mammalia, Docodonta). Postilla 139: 1–24Google Scholar
  39. Ji Q, Luo Z-X, Yuan C-X, Tabrum AR (2006) A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals. Science 311: 1123–1127CrossRefPubMedGoogle Scholar
  40. Kermack KA, Kermack D, Lees PM, Mills JRE (1998) New multituberculate-like mammals from the Middle Jurassic of England. Acta Palaeontol Pol 43: 581–606Google Scholar
  41. Kermack KA, Lee AJ, Lees PM, Mussett F (1987) A new docodont from the Forest Marble. Zool J Linn Soc 89: 1–39CrossRefGoogle Scholar
  42. Kermack KA, Mussett F (1958) The jaw articulation of the Docodonta and the classification of Mesozoic mammals. Proc Roy Soc Lond 149: 204–215CrossRefGoogle Scholar
  43. Kermack KA, Mussett F, Rigney HW (1973) The lower jaw of Morganucodon. Zool J Linn Soc 53: 87–175CrossRefGoogle Scholar
  44. Kielan-Jaworowska Z, Cifelli RL, Luo Z-X (2004) Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure. Columbia University Press, New York, 630 ppCrossRefGoogle Scholar
  45. Kobayashi Y, Winkler DA, Jacobs LL (2002) Origin of the tooth-replacement pattern in therian mammals: evidence from a 110 Myr old fossil. Proc Roy Soc Lond 269: 369–373CrossRefGoogle Scholar
  46. Koenigswald W von, Anders U, Engels S, Schultz JA, Kullmer O (2013) Jaw movement in fossil mammals: analysis, description and visualization. Paläontol Z 87: 141–159CrossRefGoogle Scholar
  47. Kron DG (1979) Docodonta. In: Lillegraven JA, Kielan-Jaworowska Z, Clemens WA (eds) Mesozoic Mammals: The First Two-thirds of Mammalian History. University of California Press, Berkeley, pp 91–98Google Scholar
  48. Krusat G (1980) Contribuçăo para o conhecimento da fauna do Kimeridgiano da mina de lignito Guimarota (Leiria, Portugal). IV Parte. Haldanodon exspectatus Kuhne & Krusat 1972 (Mammalia, Docodonta). Mems Serv Geol Portugal 27: 1–79Google Scholar
  49. Kuhn H-J (1971). Die Entwicklung und Morphologie des Schädels von Tachyglossus aculeatus. Abhandl Senckenberg Naturforsch Gesellschaft 528: 1–192Google Scholar
  50. Kühne WG, Krusat G (1972) Legaliesierung des taxon Haldanodon (Mammalia, Docodonta). Neues Jahrbuch für Geologie, Paläontologie und Mineralogie, Monatshefte 5: 300–302.Google Scholar
  51. Kullmer O, Benazz, S, Fiorenza L, Schulz D, Bacso S, Winzen O (2009) Technical note: occlusal fingerprint analysis: quantification of tooth wear pattern. Am J Phys Anth 139: 600–605CrossRefGoogle Scholar
  52. Kullmer O, Benazzi S, Schulz D, Gunz P, Kordos L, Begun DR (2013) Dental arch restoration using tooth macrowear patterns with application to Rudapithecus hungaricus, from the late Miocene of Rudabánya. J Hum Evol 64: 151–160CrossRefPubMedGoogle Scholar
  53. Lautenschlager S, Gill P, Luo Z-X, Fagan MJ, Rayfield EJ (2016) Morphological evolution of the mammalian jaw adductor complex. Biol Rev 2016: 1910–1940. Google Scholar
  54. Lillegraven JA, Krusat G (1991) Cranio-mandibular anatomy of Haldanodon exspectatus (Docodonta; Mammalia) from the Late Jurassic of Portugal and its implications to the evolution of mammalian characters. Contrib Geol Univ Wyom 28: 39–138Google Scholar
  55. Lopatin AV, Averianov AO (2005) A new docodont (Docodonta, Mammalia) from the Middle Jurassic of Siberia. Doklady Biol Sci 405: 434–436CrossRefGoogle Scholar
  56. Lopatin AV, Averianov AO, Maschenko EN, Leshchinskiy SV (2009) Early Cretaceous Mammals of western Siberia: 2. Tegotheriidae. Paleontol J 43: 453–462CrossRefGoogle Scholar
  57. Luo Z-X (2011) Developmental patterns in Mesozoic evolution of mammal ears. Annu Rev Ecol Evol Syst 42: 355–380. CrossRefGoogle Scholar
  58. Luo Z-X, Crompton AW, Sun A-L (2001) A new mammaliaform from the Early Jurassic of China and evolution of mammalian characteristics. Science 292: 1535–1540CrossRefPubMedGoogle Scholar
  59. Luo Z-X, Gatesy SM, Jenkins FA, Amaral AA, Shubin NH (2015b) Mandibular and dental characteristics of Late Triassic mammaliaform Haramiyavia and their ramifications for basal mammal evolution. Proc Natl Acad Sci USA 112 (51): E7101–E7109. PubMedPubMedCentralGoogle Scholar
  60. Luo Z-X, Ji Q (2005) New study on dental and skeletal features of the Cretaceous mammal Zhangheotherium. J Mammal Evol 12: 337–357.CrossRefGoogle Scholar
  61. Luo Z-X, Kielan-Jaworowska Z, Cifelli RL (2004) Evolution of dental replacement in mammals. Bull Carnegie Mus Nat Hist 36: 159–175CrossRefGoogle Scholar
  62. Luo Z-X, Martin T (2007) Analysis of molar structure and phylogeny of docodontan genera. Bull Carnegie Mus Nat Hist 39: 27–47.CrossRefGoogle Scholar
  63. Luo Z-X, Meng Q-J, Grossnickle DM, Liu D, Zhang Y-G, Neander AI, Ji Q (2017) New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem. Nature 548: 326–329. doi: CrossRefPubMedGoogle Scholar
  64. Luo Z-X, Meng Q-J, Ji Q, Liu D, Zhang Y-G, Neander AI (2015a) Evolutionary development in basal mammaliaforms as revealed by a docodontan. Science 347: 760–764CrossRefPubMedGoogle Scholar
  65. Luo Z-X, Schultz JA, Ekdale EG (2016) Evolution of the middle and inner ears of mammaliaforms: the approach to mammals. In: Clack JA, Fay RR, Popper AN (eds) Evolution of the Vertebrate Ear: Evidence from the Fossil Record. Springer Handbooks for Auditory Research 59:139–174. CrossRefGoogle Scholar
  66. Marsh OC (1880) Notice on Jurassic mammals representing two new orders. Am J Sci 20: 235–239CrossRefGoogle Scholar
  67. Marsh OC (1881) Notice of new Jurassic mammals. Am J Sci 21: 511–513CrossRefGoogle Scholar
  68. Marsh OC (1887) American Jurassic mammals. Am J Sci 33: 326–348Google Scholar
  69. Martin T (1997) Tooth replacement in Late Jurassic Dryolestidae (Eupantotheria, Mammalia). J Mammal Evol 4: 1–18CrossRefGoogle Scholar
  70. Martin T (2005) Postcranial anatomy of Haldanodon exspectatus (Mammalia, Docodonta) from the Late Jurassic (Kimmeridgian) of Portugal and its bearing for mammalian evolution. Zool J Linn Soc 145: 219–248. CrossRefGoogle Scholar
  71. Martin T, Averianov AO (2004) A new docodont (Mammalia) from the Middle Jurassic of Kyrgyzstan, central Asia. J Vertebr Paleontol 24: 195–201CrossRefGoogle Scholar
  72. Martin T, Averianov AO, Pfretzschner H-U (2010a) Mammals from the Late Jurassic Qigu Formation in the southern Junggar Basin, Xinjiang, Northwest China. Palaeobiod & Palaeoenviron 90: 295–319CrossRefGoogle Scholar
  73. Martin T, Nowotny M (2000) The docodont Haldanodon from the Guimarota Mine. In: Martin T, Krebs B (eds) Guimarota: A Jurassic Ecosystem. Verlag Dr. Friedrich Pfeil, Munich, pp 91–96Google Scholar
  74. Martin T, Nowotney M, Fischer M (2010b) New data on tooth replacement in the late Jurassic docodont mammal Haldanodon exspectatus. Society of Vertebrate Paleontology 70th Annual Meeting (2010) Program and Abstracts: 130AGoogle Scholar
  75. Menegaz RA, Baier DB, Metzger KA, Herring SW, Brainerd EL (2015) XROMM analysis of tooth occlusion and temporomandibular joint kinematics during feeding in juvenile miniature pigs. J Exp Biol 218: 2573–2584CrossRefPubMedGoogle Scholar
  76. Meng Q-J, Ji Q, Zhang Y-G, Liu D, Grossnickle DM, Luo Z-X (2015) An arboreal docodont from the Jurassic and mammaliaform ecological diversification. Science 347: 764–768CrossRefPubMedGoogle Scholar
  77. Mills JRE (1967) A comparison of lateral jaw movements in some mammals from wear facets on the teeth. Arch Oral Biol 12: 645–661CrossRefPubMedGoogle Scholar
  78. Mills JRE (1971) The dentition of Morganucodon. In: Kermack DM, Kermack KA (eds) Early Mammals. Zool J Linn Soc 50, supplement 1: 29–63Google Scholar
  79. Nowotny M, Martin T, Fischer M (2001) Dental anatomy and tooth replacement of Haldanodon exspectatus (Docodonta, Mammalia) from the Upper Jurassic of Portugal. J Morphol 248: 268Google Scholar
  80. O'Meara RN, Asher RJ (2016) The evolution of growth patterns in mammalian versus nonmammalian cynodonts. Paleobiology 42: 439–464.
  81. Oron U, Crompton AW (1985) A cineradiographic and electromyographic study of mastication in Tenrec ecaudatus. J Morphol 185: 155–182Google Scholar
  82. Parrington FR (1971) On the Upper Triassic mammals. Phil Trans Roy Soc Lond B 261: 231–272CrossRefGoogle Scholar
  83. Patterson B (1956) Early Cretaceous mammals and the evolution of mammalian molar teeth. Fieldiana: Geol 13: 1–105Google Scholar
  84. Pfretzschner H-U, Martin T, Maisch M, Matze A, Sun G (2005) A new docodont from the Late Jurassic of the Junggar Basin of northwest China. Acta Palaeontol Pol 50: 799–808Google Scholar
  85. Prothero DR (1981) New Jurassic mammals from Como Bluff, Wyoming, and the interrelationships of non-tribosphenic Theria. Bull Am Mus Nat Hist 167: 277–326Google Scholar
  86. Ramírez-Chaves HE, Wroe SW, Selwood L, Hinds LA, Leigh C, Koyabu D, Kardjilov N, Weisbecker V (2016) Mammalian development does not recapitulate suspected key transformations in the evolutionary detachment of the mammalian middle ear. Proc Roy Soc B 283: 20152606. CrossRefGoogle Scholar
  87. Rougier GW, Sheth AS, Carpenter K, Appella-Guiscafre L, Davis BM (2015) A new species of Docodon (Mammaliaformes: Docodonta) from the Upper Jurassic Morrison Formation and a reassessment of selected craniodental characters in basal mammaliaforms. J Mammal Evol 22:1–16. CrossRefGoogle Scholar
  88. Ruf I, Luo Z-X, Martin T (2013) Re-investigation of the basicranium of Haldanodon exspectatus (Docodonta, Mammaliaformes). J Vertebr Paleontol 33:382–400CrossRefGoogle Scholar
  89. Sánchez-Villagra MR, Gemballa S, Nummela S, Smith KK, Maier W (2002) Ontogenetic and phylogenetic transformations of the ear ossicles in marsupial mammals. J Morphol 251: 219–238CrossRefPubMedGoogle Scholar
  90. Sigogneau-Russell D (2003) Docodonts from the British Mesozoic. Acta Palaeontol Pol 48: 357–374Google Scholar
  91. Sigogneau-Russell D, Godefroit P (1997) A primitive docodont (Mammalia) from the Upper Triassic of France and the possible therian affinities of the order. Comptes Rendus de l’Académie des Sciences 324:135–140Google Scholar
  92. Simpson GG (1928) Mesozoic Mammalia, XII; the internal mandibular groove of Jurassic mammals. Am J Sci 5-15: 461–470CrossRefGoogle Scholar
  93. Simpson GG (1929) American Mesozoic Mammalia. Mem Peabody Mus Yale Univ 3: 1–235Google Scholar
  94. Schultz JA, Martin T (2014) Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation. Naturwissenschaften 101: 771–781CrossRefPubMedGoogle Scholar
  95. Turnbull WD (1970) Mammalian masticatory apparatus. Fieldiana: Geol 18: 147–356Google Scholar
  96. Ungar PS (2010) Mammal Teeth: Origin, Evolution, and Diversity. The Johns Hopkins University Press, Baltimore, 304 ppGoogle Scholar
  97. Urban DJ, Anthwal N, Luo Z-X, Maier JA, Sadier A, Tucker AS, Sears KE (2017) A new developmental mechanism for the separation of the mammalian middle ear ossicles from the jaw. Proc Roy Soc B – Biol Sci 284: 20162416. CrossRefGoogle Scholar
  98. Williams SH, Vinyard CJ, Wall CE, Doherty AH, Crompton AW, Hylander WL (2011) A preliminary analysis of correlated evolution in mammalian chewing motor patterns. Integrat Comp Biol 51: 247–259Google Scholar
  99. Waldman M, Savage RJG (1972) The first Jurassic mammal from Scotland. J Geol Soc 128: 119–125CrossRefGoogle Scholar
  100. Yuan C-X, Ji Q, Meng Q-J, Luo Z-X (2013) Earliest evolution of multituberculate mammals revealed by a new Jurassic fossil. Science 341: 779–783CrossRefPubMedGoogle Scholar
  101. Zeller U (1989) Die Enwicklung und Morphologie des Schädels von Ornithorhynchus anatinus (Mammalia: Prototheria: Monotremata). Abhandl Senckenberg Naturforsch Gesellschaft 545: 1–188Google Scholar
  102. Zhang F-K, Crompton AW, Luo Z-X, Schaff CR (1998) Pattern of dental replacement of Sinoconodon and its implications for evolution of mammals. Vertebr PalAsiatica 36: 197–217 (in both Chinese and English)Google Scholar
  103. Zhou C-F, Wu S, Martin T, Luo Z-X (2013) A Jurassic mammaliaform and the earliest mammalian evolutionary adaptations. Nature 500: 163–168. CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2017

Authors and Affiliations

  1. 1.Department of Organismal Biology and AnatomyThe University of ChicagoChicagoUSA
  2. 2.Department of Geology and Geophysics and Peabody Museum of Natural HistoryYale UniversityNew HavenUSA

Personalised recommendations