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A Jurassic eutherian mammal and divergence of marsupials and placentals


Placentals are the most abundant mammals that have diversified into every niche for vertebrates and dominated the world’s terrestrial biotas in the Cenozoic. A critical event in mammalian history is the divergence of eutherians, the clade inclusive of all living placentals, from the metatherian–marsupial clade1,2,3,4,5,6,7,8. Here we report the discovery of a new eutherian of 160 Myr from the Jurassic of China, which extends the first appearance of the eutherian–placental clade by about 35 Myr from the previous record, reducing and resolving a discrepancy between the previous fossil record and the molecular estimate for the placental–marsupial divergence9,10,11,12,13. This mammal has scansorial forelimb features, and provides the ancestral condition for dental and other anatomical features of eutherians.

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Figure 1: Holotype specimen of Juramaia sinensis , Beijing Museum of Natural History (BMNH) PM1343B.
Figure 2: Dental and mandibular features of Juramaia sinensis (BMNH PM1343B).
Figure 3: Time-calibrated phylogeny of the eutherian Juramaia among other boreosphenidan mammals, and comparative morphology of some key molar features.

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  1. Kielan-Jaworowska, Z., Cifelli, R. L. & Luo, Z.-X. Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure (Columbia Univ. Press, 2004)

    Book  Google Scholar 

  2. Luo, Z.-X. Transformation and diversification in the early mammalian evolution. Nature 450, 1011–1019 (2007)

    Article  ADS  CAS  Google Scholar 

  3. Ji, Q. et al. The earliest known eutherian mammal. Nature 416, 816–822 (2002)

    Article  ADS  CAS  Google Scholar 

  4. Wible, J. R., Rougier, G. W., Novacek, M. J. & Asher, R. J. The eutherian mammal Maelestes gobiensis from the Late Cretaceous of Mongolia and the phylogeny of Cretaceous Eutheria. Bull. Am. Mus. Nat. Hist. 327, 1–123 (2009)

    Article  Google Scholar 

  5. Hu, Y. M., Meng, J., Li, C.-K. & Wang, Y.-Q. New basal eutherian mammal from the Early Cretaceous Jehol biota, Liaoning, China. Proc. R. Soc. B 277, 229–236 (2010)

    Article  Google Scholar 

  6. Rougier, G. W., Wible, J. R. & Novacek, M. J. Implications of Deltatheridium specimens for early marsupial history. Nature 396, 459–463 (1998)

    Article  ADS  CAS  Google Scholar 

  7. Luo, Z.-X., Ji, Q., Wible, J. R. & Yuan, C.-X. An Early Cretaceous tribosphenic mammal and metatherian evolution. Science 302, 1934–1940 (2003)

    Article  ADS  CAS  Google Scholar 

  8. Wilson, G. P. & Riedl, J. A. New specimen reveals deltatheroidan affinities of the North American Late Cretaceous mammal Nanocuris . J. Vertebr. Paleontol. 30, 872–884 (2010)

    Article  Google Scholar 

  9. van Rheede, T. et al. The platypus is in its place: nuclear genes and Indels confirm the sister group relation of monotremes and therians. Mol. Biol. Evol. 23, 587–597 (2006)

    Article  CAS  Google Scholar 

  10. Kitazoe, Y. et al. Robust time estimation reconciles views of the antiquity of placental mammals. PLoS ONE 2, e384 (2007)

    Article  ADS  Google Scholar 

  11. Bininda-Emonds, O. R. P. et al. The delayed rise of present-day mammals. Nature 446, 507–512 (2007)

    Article  ADS  CAS  Google Scholar 

  12. Phillips, M. J., Bennett, T. H. & Lee, M. S. Y. Molecules, morphology, and ecology indicate a recent, amphibious ancestry for echidnas. Proc. Natl Acad. Sci. USA 106, 17089–17094 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Benton, M. J., Donoghue, P. C. J. & Asher, R. J. in The Timetree of Life (eds Hedges, S. B. & Kumar, S. ) 35–86 (Oxford Univ. Press, 2009)

    Google Scholar 

  14. Luo, Z.-X., Cifelli, R. C. & Kielan-Jaworowska, Z. Dual origin of tribosphenic mammals. Nature 409, 53–57 (2001)

    Article  ADS  CAS  Google Scholar 

  15. Liu, Y.-Q., Liu, Y.-X., Ji, S.-A. & Yang, Z.-Q. U-Pb zircon age for the Daohugou Biota at Ningcheng of Inner Mongolia and comments on related issues. Chin. Sci. Bull. 51, 2634–2644 (2006)

    Article  CAS  Google Scholar 

  16. Chang, S.-C., Zhang, H.-C., Renne, P. R. & Fang, F. High-precision 40Ar/39Ar age constraints on the basal Lanqi Formation and its implications for the origin of angiosperm plants. Earth Planet. Sci. Lett. 279, 212–221 (2009)

    Article  ADS  CAS  Google Scholar 

  17. Crompton, A. W. & Kielan-Jaworowska, Z. in Studies in the Development, Function and Evolution of Teeth (eds Butler, P. M. & Joysey, K. A. ) 249–287 (Academic Press, 1978)

    Google Scholar 

  18. Cifelli, R. L. & de Muizon, C. Dentition and jaw of Kokopellia juddi, a primitive marsupial or near marsupial from the medial Cretaceous of Utah. J. Mamm. Evol. 4, 241–258 (1997)

    Article  Google Scholar 

  19. Averianov, A. O., Archibald, J. D. & Ekdale, E. G. New material of the Late Cretaceous deltatheroidan mammal Sulestes from Uzbekistan and phylogenetic reassessment of the metatherian eutherian dichotomy. J. Syst. Palaeontology 8, 301–330 (2010)

    Article  Google Scholar 

  20. Cifelli, R. L. et al. Origin of marsupial pattern of tooth replacement: fossil evidence revealed by high resolution X-ray CT. Nature 379, 715–718 (1996)

    Article  ADS  CAS  Google Scholar 

  21. Rich, T. H. et al. Early Cretaceous mammals from Flat Rocks, Victoria, Australia. Rec. Queen Victoria Mus. 106, 1–35 (1999)

    Google Scholar 

  22. Martin, T. & Rauhut, O. W. M. Mandible and dentition of Asfaltomylos patagonicus (Australosphenida, Mammalia) and the evolution of tribosphenic teeth. J. Vertebr. Paleontol. 25, 414–425 (2005)

    Article  Google Scholar 

  23. Rougier, G. W. et al. New Jurassic mammals from Patagonia, Argentina: a reappraisal of australosphenidan morphology and interrelationship. Am. Mus. Novit. 3566, 1–54 (2007)

    Article  Google Scholar 

  24. Luo, Z.-X., Ji, Q. & Yuan, C.-X. Convergent dental evolution in pseudotribosphenic and tribosphenic mammals. Nature 450, 93–97 (2007)

    Article  ADS  CAS  Google Scholar 

  25. Kielan-Jaworowska, Z. & Dashzeveg, D. Eutherian mammals from the Early Cretaceous of Mongolia. Zool. Scr. 18, 347–355 (1989)

    Article  Google Scholar 

  26. Averianov, A. O. & Skutschas, P. P. A new genus of eutherian mammal from the Early Cretaceous of Transbaikalia, Russia. Acta Palaeontol. Pol. 46, 431–436 (2001)

    Google Scholar 

  27. Sigogneau-Russell, D., Hooker, J. J. & Ensom, P. C. The oldest tribosphenic mammal from Laurasia (Purbeck Limestone Group, Berriasian, Cretaceous, UK) and its bearing on the ‘dual origin’ of Tribosphenida. C. R. Acad. Sci. II 333, 141–147 (2001)

    Google Scholar 

  28. Argot, C. Functional-adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus . J. Morphol. 247, 51–79 (2001)

    Article  CAS  Google Scholar 

  29. Asher, R. J., Horovitz, I. & Sanchez-Villagra, M. R. First combined cladistic analysis of marsupial mammal interrelationships. Mol. Phylogenet. Evol. 33, 240–250 (2004)

    Article  CAS  Google Scholar 

  30. Kirk, E. C., Lemelin, P., Hamrick, M. W., Boyer, D. M. & Bloch, J. I. Intrinsic hand proportions of euarchontans and other mammals: Implications for the locomotor behavior of plesiadapiforms. J. Hum. Evol. 55, 278–299 (2008)

    Article  Google Scholar 

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We thank A. R. Tabrum for his meticulous preparation of the fossil, Y.-Q. Zhang for casting, and M. A. Klingler for assistance with graphics. During this work, we benefited from discussion with Y.-Q. Liu on field geology and dating, and with R. J. Asher, K. C. Beard, R. L. Cifelli, M. R. Dawson, T. Martin and J. R. Wible for discussion on mammal phylogeny. J. Wible and M. Dawson helped to improve the manuscript. Support was given to Z.-X.L. from the National Science Foundation (USA), to C.-X.Y. from the National Natural Science Foundation-China and the Chinese Academy of Geological Sciences, and to Q.J. from the 973 Project of the Ministry of Science and Technology of China and funding from the Chinese Academy of Geological Sciences.

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Z.-X.L. and Q.J. designed the research plan. All authors participated in morphological studies. Z.-X.L. and C.-X.Y. performed phylogenetic analyses. Z.-X.L. wrote the paper with discussion from all authors.

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Correspondence to Zhe-Xi Luo.

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Luo, ZX., Yuan, CX., Meng, QJ. et al. A Jurassic eutherian mammal and divergence of marsupials and placentals. Nature 476, 442–445 (2011).

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