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A Jurassic mammal from South America


The Jurassic period is an important stage in early mammalian evolution, as it saw the first diversification of this group, leading to the stem lineages of monotremes and modern therian mammals1. However, the fossil record of Jurassic mammals is extremely poor, particularly in the southern continents. Jurassic mammals from Gondwanaland are so far only known from Tanzania2,3 and Madagascar4, and from trackway evidence from Argentina5. Here we report a Jurassic mammal represented by a dentary, which is the first, to our knowledge, from South America. The tiny fossil from the Middle to Late Jurassic of Patagonia is a representative of the recently termed Australosphenida, a group of mammals from Gondwanaland that evolved tribosphenic molars convergently to the Northern Hemisphere Tribosphenida, and probably gave rise to the monotremes1. Together with other mammalian evidence from the Southern Hemisphere2,3,4,6,7,8, the discovery of this new mammal indicates that the Australosphenida had diversified and were widespread in Gondwanaland well before the end of the Jurassic, and that mammalian faunas from the Southern Hemisphere already showed a marked distinction from their northern counterparts by the Middle to Late Jurassic.

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Figure 1: Camera lucida drawings of the left mandible of Asfaltomylos patagonicus (holotype).
Figure 2: Dentition of the holotype of Asfaltomylos patagonicus.
Figure 3: Phylogenetic position of Asfaltomylos.


  1. 1

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

    ADS  CAS  Article  Google Scholar 

  2. 2

    Heinrich, W.-D. Late Jurassic mammals from Tendaguru, Tanzania, East Africa. J. Mamm. Evol. 5, 269–290 (1998).

    Article  Google Scholar 

  3. 3

    Heinrich, W.-D. First haramiyid (Mammalia, Allotheria) from the Mesozoic of Gondwana. Mitt. Mus. Naturk. Berl., Geowiss. 2, 159–170 (1999).

    Google Scholar 

  4. 4

    Flynn, J. J., Parrish, J. M., Rakotosamimanana, B., Simpson, W. F. & Wyss, A. R. A Middle Jurassic mammal from Madagascar. Nature 401, 57–60 (1999).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Casamiquela, R. M. Sobre la presencia de un mamífero en el primer elenco (icnológico) de vertebrados del Jurásico de la Patagonia. Physis 22, 225–233 (1961).

    Google Scholar 

  6. 6

    Archer, M., Flannery, T. F., Ritchie, A. & Molnar, R. First Mesozoic mammal from Australia—an Early Cretaceous monotreme. Nature 318, 363–366 (1985).

    ADS  Article  Google Scholar 

  7. 7

    Rich, T. H. et al. A tribosphenic mammal from the Mesozoic of Australia. Science 278, 1438–1442 (1997).

    ADS  CAS  Article  Google Scholar 

  8. 8

    Rich, T. H. et al. A second tribosphenic mammal from the Mesozoic of Australia. Rec. Queen Vict. Mus. 110, 1–10 (2001).

    Google Scholar 

  9. 9

    McKenna, M. C. & Bell, S. Classification of Mammals Above the Species Level (Columbia Univ. Press, New York, 1997).

    Google Scholar 

  10. 10

    Wible, J. R., Rougier, G. W., Novacek, M. J., McKenna, M. C. & Dashzeveg, D. D. A mammalian petrosal from the Early Cretaceous of Mongolia: implications for the evolution of the ear region and mammaliamorph relationships. Am. Mus. Novit. 3149, 1–19 (1995).

    Google Scholar 

  11. 11

    Tasch, P. & Volkheimer, W. Jurassic conchostracans from Patagonia. Univ. Kansas, Paleont. Contrib. 50, 1–23 (1970).

    Google Scholar 

  12. 12

    Musacchio, E. A., Beros, C. & Pujana, I. in Bioestratigrafía de los Sistemas Regionales del Jurásico y el Cretácico de América del Sur Vol. 1 (ed. Volkheimer, W.) 355–383 (CRICYT, Mendoza, 1986).

    Google Scholar 

  13. 13

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

    Google Scholar 

  14. 14

    Luo, Z.-X., Kielan-Jaworowska, Z. & Cifelli, R. L. In quest for a phylogeny of early mammals. Acta Palaeont. Pol. 47, 1–78 (2002).

    Google Scholar 

  15. 15

    Kermack, K. A., Mussett, F. & Rigney, H. W. Lower jaw of Morganucodon. Zool. J. Linn. Soc. 53, 87–175 (1973).

    Article  Google Scholar 

  16. 16

    Luo, Z.-X. in In the Shadow of the Dinosaurs—Early Mesozoic Tetrapods (eds Fraser, N. C. & Sues, H.-D.) 98–128 (Cambridge Univ. Press, Cambridge, 1994).

    Google Scholar 

  17. 17

    Kielan-Jaworowska, Z., Cifelli, R. L. & Luo, Z.-X. Alleged Cretaceous placentals from down under. Lethaia 31, 267–268 (1998).

    Article  Google Scholar 

  18. 18

    Clemens, W. A. & Mills, J. R. E. Review of Peramus tenuirostris Owen (Eupantotheria, Mammalia). Bull. Brit. Mus. (Nat. Hist.) Geol. 20, 89–113 (1971).

    Google Scholar 

  19. 19

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

    Article  Google Scholar 

  20. 20

    Krause, D. W., Prasad, G. V. R., Koenigswald, W. von, Sahni, A. & Grine, F. E. Cosmopolitanism among Late Cretaceous mammals. Nature 390, 504–507 (1997).

    ADS  CAS  Article  Google Scholar 

  21. 21

    Bonaparte, J. F. Approach to the significance of the Late Cretaceous mammals of South America. Berliner Geowiss. Abh. E 13, 31–44 (1994).

    Google Scholar 

  22. 22

    Bonaparte, J. F. Cretaceous tetrapods of Argentina. Münchener Geowiss. Abh. A 30, 73–130 (1996).

    Google Scholar 

  23. 23

    Pascual, R., Goin, F. J., González, P., Ardolino, A. & Puerta, P. F. A highly derived docodont from the Patagonian Late Cretaceous: evolutionary implications for Gondwanan mammals. Geodiversitas 22, 395–414 (2000).

    Google Scholar 

  24. 24

    Pascual, R., Goin, F. J., Krause, D. W., Ortiz Jaureguizar, E. & Carlini, A. A. The first gnathic remains of Sudamerica: implications for gondwanathere relationships. J. Vert. Paleont. 12, 373–382 (1999).

    Article  Google Scholar 

  25. 25

    Pascual, R. et al. The first discovery of monotremes in South America. Nature 356, 704–705 (1992).

    ADS  Article  Google Scholar 

  26. 26

    Pascual, R. et al. in Platypus and Echidnas (ed. Augee, M. L.) 1–14 (The Royal Society of New South Wales, Sydney, 1992).

    Google Scholar 

  27. 27

    Simpson, G. G. A Catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum (British Museum of Natural History, London, 1928).

    Google Scholar 

  28. 28

    Hahn, G. Beiträge zur Fauna der Grube Guimarota Nr. 3. Die Multituberculata. Palaeontographica A 133, 1–100.

  29. 29

    Martin, T. Dryolestidae (Dryolestoidea, Mammalia) aus dem Oberen Jura von Portugal. Abh. Senckenberg. Naturforsch. Ges. 550, 1–119.

  30. 30

    Martin, T. & Krebs, B. (eds) Guimarota. A Jurassic Ecosystem (Friedrich Pfeil, Munich, 2000).

    Google Scholar 

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We thank E. Eggert for preparation of the specimen, M. Bulang-Lörcher for drawing Fig. 1, U. Gloy for electronic figures and W. Müller for assisting at the scanning electron microscope (SEM). We also thank J. Habersetzer for carrying out the high-resolution X-ray analysis. The manuscript benefitted from comments by Z. Kielan-Jaworowska. This work was supported by a Deutscher Akademischer Austauschdienst (DAAD) fellowship to O.R., a Deutsche Forschungsgemeinschaft (DFG) Heisenberg fellowship to T.M., and an Antorchas grant to the MPEF.

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Correspondence to Thomas Martin.

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Rauhut, O., Martin, T., Ortiz-Jaureguizar, E. et al. A Jurassic mammal from South America. Nature 416, 165–168 (2002).

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