Paläontologische Zeitschrift

, Volume 89, Issue 2, pp 197–206 | Cite as

Stem therian mammal Amphibetulimus from the Middle Jurassic of Siberia

  • Alexander AverianovEmail author
  • Thomas Martin
  • Alexey Lopatin
  • Sergei Krasnolutskii
Research Paper


Amphibetulimus krasnolutskii is known from the Middle Jurassic (Bathonian) Itat Formation of Krasnoyarsk Territory, West Siberia, Russia, by several edentulous and three dentigerous dental fragments, preserving p1, antepenultimate, and ultimate lower molars, and by an upper molar. It is unique among stem therians by widely open trigonids on the posterior lower molars, paraconids that are higher than the metaconids and have keeled mesiolingual vertical crests, pronounced unilateral hypsodonty of the lower molars and correlated unequal alveolar borders of the dentary ramus, and a linear Meckelian groove that is not connected to the mandibular foramen and extends along the pterygoid ridge. Amphibetulimus differs from more derived stem therians by a simple unicuspid talonid without an incipient talonid basin and a distinct labial cingulum on the upper molars. The lack of an ectotympanic facet and the long linear Meckelian groove extending onto the pterygoid ridge suggest that Amphibetulimus had a derived state of the transitional mammalian middle ear, where the ear ossicles were connected to the dentary not by a thick “ossified” Meckelian cartilage, but by a thin Meckelian cartilage, as in prenatal and early postnatal stages of some modern therians.


Mammalia Stem Theria Middle Jurassic Asia 


Von Amphibetulimus krasnolutzkii liegen aus der mitteljurassischen (Bathon) Itat-Formation in der Region Krasnoyarsk in West-Sibirien (Russland) mehrere Unterkiefer-Fragmente und ein oberer Molar vor. In drei Kieferfragmenten sind Zähne überliefert, ein p1 sowie Molaren aus vor-vorletzter und letzter Position. Amphibetulimus unterscheidet sich von anderen Stamm-Theria durch ein weit geöffnetes Trigonid und den hinteren unteren Molaren, Paraconide, die höher als die Metaconide sind und einen gekielten mesiolingualen vertikalen Grat besitzen, ausgeprägte einseitige Hypsodontie an den unteren Molaren und damit verbundene ungleich hohe Alveolarränder am Dentale, sowie eine gerade Meckel′sche Rinne, die sich entlang des Pterygoid-Schelfs erstreckt und nicht mit dem Mandibular-Foramen in Verbindung steht. Amphibetulimus unterscheidet sich von stärker abgeleiteten Stamm-Theria durch ein einfaches einhöckeriges Talonid ohne angedeutete Beckenbildung und ein deutlich ausgeprägtes labiales Cingulum an den oberen Molaren. Das Fehlen einer Facette für das Ectotympanicum und die lange, gerade Meckel′sche Rinne, die sich auf den Pterygoid-Schelf erstreckt legen nahe, dass Amphibetulimus ein fortgeschrittenes Stadium des Übergangs zum Säugetier-Mittelohr (transitional mammalian middle ear) erreicht hatte, in dem die Gehörknöchelchen nicht durch einen dicken, “ossifizierten”, sondern einen dünnen Meckel′schen Knorpel mit dem Dentale verbunden waren, wie in pränatalen und manchmal postnatalen Stadien moderner Theria.


Mammalia Stamm-Theria Mittlerer Jura Asien 



This study was supported by the Deutsche Forschungsgemeinschaft (DFG) grant MA 1643/14-1, the Board of the President of the Russian Federation (MD-802.2009.4), the Russian Foundation for Basic Research (projects 07-04-00393, 10-04-01350, 13-04-01401, and 11-04-91331-NNIO), and the Program of the Presidium of the Russian Academy of Sciences “Origin of the Life and Establishment of Biosphere”. G. Oleschinski (Bonn) assisted at the SEM. AA is grateful to A. Bochkov (Saint Petersburg) for discussion of character-weighting methods. For assistance in the field and/or picking the concentrate, we thank I. Danilov, D. Grigoriev, R. Hielscher, K. Jäger, J. Könen, S. Krasnolutskii, D. Rohkamp, R. Schellhorn, J. Schultz, A. Schwermann, L. Schwermann, P. Skutschas, E. Syromyatnikova, and A. Valeev. We are grateful to reviewer L. Gaetano and editor G. Rougier for providing helpful comments on the manuscript.


  1. Alifanov, V.R., S.A. Krasnolutskii, V.N. Markov, and N.V. Martynovich. 2001. About discovery of the Middle Jurassic dinosaurs in the Krasnoyarsk Territory. In Scientific-Practical Conference “Problems of the Struggle Against Illegal Excavations and Illegal Turnover of the Objects of Archaeology, Mineralogy, and Palaeontology”, 71–74. Krasnoyarsk.Google Scholar
  2. Allin, E.F. 1975. Evolution of the mammalian middle ear. Journal of Morphology 147: 403–436.CrossRefGoogle Scholar
  3. Allin, E.F., and J.A. Hopson. 1992. Evolution of the auditory system in Synapsida (“mammal-like reptiles” and primitive mammals) as seen in the fossil record. In The evolutionary biology of hearing, ed. D.B. Webster, R.R. Fay, and A.N. Popper, 587–614. New York: Springer.CrossRefGoogle Scholar
  4. Averianov, A.O., and S.A. Krasnolutskii. 2009. Stegosaur remains from the Middle Jurassic of West Siberia. Proceedings of the Zoological Institute of the Russian Academy of Sciences 313: 59–73.Google Scholar
  5. Averianov, A.O., S.A. Krasnolutskii, and S.V. Ivantsov. 2010a. A new basal coelurosaur (Dinosauria: Theropoda) from the Middle Jurassic of Siberia. Proceedings of the Zoological Institute of the Russian Academy of Sciences 314: 42–57.Google Scholar
  6. Averianov, A.O., and A.V. Lopatin. 2006. Itatodon tatarinovi (Tegotheriidae, Mammalia), a docodont from the Middle Jurassic of Western Siberia and phylogenetic analysis of Docodonta. Paleontological Journal 40: 668–677.CrossRefGoogle Scholar
  7. Averianov, A.O., A.V. Lopatin, and S.A. Krasnolutskii. 2008. An amphilestid grade eutriconodontan from the Middle Jurassic of Russia. Russian Journal of Theriology 7: 1–4.Google Scholar
  8. Averianov, A.O., A.V. Lopatin, and S.A. Krasnolutskii. 2011. The first Haramiyid (Mammalia, Allotheria) from the Jurassic of Russia. Doklady Biological Sciences 437: 422–425.CrossRefGoogle Scholar
  9. Averianov, A.O., A.V. Lopatin, S.A. Krasnolutskii, and S.V. Ivantsov. 2010b. New docodontans from the Middle Jurassic of Siberia and reanalysis of Docodonta interrelationships. Proceedings of the Zoological Institute of the Russian Academy of Sciences 314: 121–148.Google Scholar
  10. Averianov, A.O., A.V. Lopatin, P.P. Skutschas, N.V. Martynovich, S.V. Leshchinskiy, A.S. Rezvyi, S.A. Krasnolutskii, and A.V. Fayngerts. 2005. Discovery of Middle Jurassic Mammals from Siberia. Acta Palaeontologica Polonica 50: 789–797.Google Scholar
  11. Averianov, A.O., T. Martin, and A.V. Lopatin. 2013. A new phylogeny for basal Trechnotheria and Cladotheria and affinities of South American endemic Late Cretaceous mammals. Naturwissenschaften 100: 311–326.CrossRefGoogle Scholar
  12. Averianov, A.O., T. Martin, and A.V. Lopatin. 2013. The oldest dryolestid mammal from the Middle Jurassic of Siberia. Journal of Vertebrate Paleontology (in press).Google Scholar
  13. Dashzeveg, D., and Z. Kielan-Jaworowska. 1984. The lower jaw of an aegialodontid mammal from the Early Cretaceous of Mongolia. Zoological Journal of the Linnean Society 82: 217–227.CrossRefGoogle Scholar
  14. Fox, R.C. 1975. Molar structure and function in the Early Cretaceous mammal Pappotherium: evolutionary implications for Mesozoic Theria. Canadian Journal of Earth Sciences 12: 412–442.CrossRefGoogle Scholar
  15. Goloboff, P.A., J.S. Farris, and K.C. Nixon. 2003. Tree analysis using new technology. Program and documentation available from the authors (and at
  16. Ji, Q., Z.-X. Luo, C.-X. Yuan, J.R. Wible, J.-P. Zhang, and J.A. Georg. 2002. The earliest known eutherian mammal. Nature 416: 816–822.CrossRefGoogle Scholar
  17. Kermack, K.A., F. Mussett, and H.W. Rigney. 1973. The lower jaw of Morganucodon. Zoological Journal of the Linnean Society 53: 87–175.CrossRefGoogle Scholar
  18. Kielan-Jaworowska, Z., R.L. Cifelli, and Z.-X. Luo. 2004. Mammals from the age of dinosaurs: origins, evolution, and structure. New York: Columbia University Press.Google Scholar
  19. Kielan-Jaworowska, Z., and D. Dashzeveg. 1989. Eutherian mammals from the Early Cretaceous of Mongolia. Zoologica Scripta 18: 347–355.CrossRefGoogle Scholar
  20. Li, C., T. Setoguchi, Y. Wang, Y. Hu, and Z.-L. Chang. 2005. The first record of “eupantotherian” (Theria, Mammalia) from the late Early Cretaceous of western Liaoning, China. Vertebrata PalAsiatica 43: 245–255.Google Scholar
  21. Linnaeus, C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Vol. 1: Regnum animale. Editio decima, reformata. Stockholm: Laurentii Salvii.Google Scholar
  22. Lopatin, A.V., and A.O. Averianov. 2005. A new docodont (Docodonta, Mammalia) from the Middle Jurassic of Siberia. Doklady Biological Sciences 405: 434–436.CrossRefGoogle Scholar
  23. Lopatin, A.V., and A.O. Averianov. 2006. Revision of a pretribosphenic mammal Arguimus from the Early Cretaceous of Mongolia. Acta Palaeontologica Polonica 51: 339–349.Google Scholar
  24. Lopatin, A.V., and A.O. Averianov. 2007. The earliest Asiatic pretribosphenic mammal (Cladotheria, Amphitheriidae) from the Middle Jurassic of Siberia. Doklady Biological Sciences 417: 432–434.CrossRefGoogle Scholar
  25. Luo, Z.-X. 2007. Transformation and diversification in early mammal evolution. Nature 450: 1011–1019.CrossRefGoogle Scholar
  26. Luo, Z.-X. 2011. Developmental patterns in Mesozoic evolution of mammal ears. Annual Review of Ecology, Evolution, and Systematics 42: 355–380.CrossRefGoogle Scholar
  27. Luo, Z.-X., P. Chen, G. Li, and M. Chen. 2007. A new eutriconodont mammal and evolutionary development in early mammals. Nature 446: 288–293.CrossRefGoogle Scholar
  28. Martin, T. 2002. New stem-line representatives of Zatheria (Mammalia) from the Late Jurassic of Portugal. Journal of Vertebrate Paleontology 22: 332–348.CrossRefGoogle Scholar
  29. McKenna, M.C. 1975. Towards a phylogenetic classification of the Mammalia. In Phylogeny of the primates, ed. W.P. Luckett, and F.S. Szalay, 21–46. New York: Plenum Press.CrossRefGoogle Scholar
  30. Meng, J., Y. Hu, Y. Wang, and C. Li. 2003. The ossified Meckel’s cartilage and internal groove in Mesozoic mammaliaforms: implications to origin of the definitive mammalian middle ear. Zoological Journal of the Linnean Society 138: 431–448.CrossRefGoogle Scholar
  31. Meng, J., Y. Wang, and C. Li. 2011. Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont. Nature 472: 181–185.CrossRefGoogle Scholar
  32. Nixon, K.C. 1999. Winclada (Beta) version 0.9.9. Software published by the author, Ithaca.
  33. Parker, T.J., and W.A. Haswell. 1897. A text-book of zoology, vol. 2. London: MacMillan and Company.Google Scholar
  34. Prothero, D.R. 1981. New Jurassic mammals from Como Bluff, Wyoming, and the interrelationships of non-tribosphenic Theria. Bulletin of the American Museum of Natural History 167: 281–325.Google Scholar
  35. Schultz, J.A., and T. Martin. 2010. Wear pattern and functional morphology of dryolestoid molars (Mammalia, Cladotheria). Palaeontologische Zeitschrift 85: 269–285.CrossRefGoogle Scholar
  36. Sigogneau-Russell, D. 2003. Holotherian mammals from the Forest Marble (Middle Jurassic of England). Geodiversitas 25: 501–537.Google Scholar
  37. Simpson, G.G. 1928a. A catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum. London: British Museum (Natural History).Google Scholar
  38. Simpson, G.G. 1928b. Mesozoic Mammalia. XII. The internal mandibular groove of Jurassic mammals. American Journal of Science 15: 461–470.CrossRefGoogle Scholar
  39. Skutschas, P.P. 2006. Mesozoic amphibians from Siberia, Russia. In 9th international symposium on Mesozoic terrestrial ecosystems and biota. Abstracts and proceedings volume, eds. P.M. Barrett, and S.E. Evans, 123–126, 179. Manchester.Google Scholar
  40. Skutschas, P.P., and S.A. Krasnolutskii. 2011. A new genus and species of basal salamanders from the Middle Jurassic of Western Siberia, Russia. Proceedings of the Zoological Institute of the Russian Academy of Sciences 315: 167–175.Google Scholar
  41. Skutschas, P.P., S.V. Leshchinskiy, A.S. Rezvyi, A.V. Fayngertz, and S.A. Krasnolutskii. 2005. Remains of salamanders from the Middle Jurassic of the Krasnoyarsk Territory. In Modern paleontology: classical and newest methods, ed. A.Y. Rozanov, A.V. Lopatin, and P.Y. Parkhaev, 121–124. Moscow: Paleontological Institute of the Russian Academy of Sciences.Google Scholar
  42. Valeev, A.K.-M. 2008. First lizard records in the Jurassic of Russia. Vestnik Sankt-Peterburgskogo Universiteta, Seriya 3: 86–89.Google Scholar
  43. Wang, Y., Y. Hu, J. Meng, and C. Li. 2001. An ossified Meckel’s cartilage in two Cretaceous mammals and the origin of the mammalian middle ear. Science 294: 357–361.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Alexander Averianov
    • 1
    • 2
    Email author
  • Thomas Martin
    • 3
  • Alexey Lopatin
    • 4
  • Sergei Krasnolutskii
    • 5
  1. 1.Zoological Institute of the Russian Academy of SciencesSaint PetersburgRussia
  2. 2.Department of Sedimentary Geology, Geological FacultySaint Petersburg State UniversitySaint PetersburgRussia
  3. 3.Steinmann-Institut für Geologie, Mineralogie und PaläontologieUniversität BonnBonnGermany
  4. 4.Borissiak Paleontological Institute of the Russian Academy of SciencesMoscowRussia
  5. 5.Sharypovo Regional MuseumKrasnoyarskRussia

Personalised recommendations