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Tribosphenic mammal from the North American Early Cretaceous

Nature volume 401, pages 363–366 (1999)Cite this article

A Corrigendum to this article was published on 20 April 2000

Abstract

The main groups of living mammals, marsupials and eutherians, are presumed to have diverged in the Early Cretaceous1, but their early history and biogeography are poorly understood. Dental remains have suggested that the eutherians may have originated in Asia2, spreading to North America in the Late Cretaceous, where an endemic radiation of marsupials was already well underway3. Here I describe a new tribosphenic mammal (a mammal with lower molar heels that are three-cusped and basined) from the Early Cretaceous of North America, based on an unusually complete specimen. The new taxon bears characteristics (molarized last premolar, reduction to three molars) otherwise known only for Eutheria among the tribosphenic mammals. Morphometric analysis and character comparisons show, however, that its molar structure is primitive (and thus phylogenetically uninformative), emphasizing the need for caution in interpretation of isolated teeth. The new mammal is approximately contemporaneous with the oldest known Eutheria from Asia. If it is a eutherian, as is indicated by the available evidence, then this group was far more widely distributed in the Early Cretaceous than previously appreciated. An early presence of Eutheria in North America offers a potential source for the continent's Late Cretaceous radiations, which have, in part, proven difficult to relate to contemporary taxa in Asia.

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Figure 1: Montanalestes keebleri gen. et sp. nov., OMNH 60793.
Figure 2: Jaws of Cretaceous tribosphenic mammals, showing distribution of selected tooth and jaw characters (some restored after refs given in Supplementary Information).
Figure 3: Comparison of lower molar shape in selected Cretaceous tribosphenic mammals and the eupantothere Peramus.

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References

  1. Lillegraven,J. A., Thompson,S. D., McNab,B. K. & Patton,J. L. The origin of eutherian mammals. Biol. J. Linn. Soc. 32, 281–336 (1987).

    Article  Google Scholar 

  2. Butler,P. M. in Structure, Function and Evolution of Teeth (eds Smith, P. & Tchernov, E.) 125–138 (Freund, Tel Aviv, 1990).

    Google Scholar 

  3. Kielan-Jaworowska,Z. in Palaeontology, Essential of Historical Geology (ed. Gallitelli, E. M.) 367–383 (S.T.E.M. Mucci, Modena, 1982).

    Google Scholar 

  4. Nessov,L. A., Archibald,J. D. & Kielan-Jaworowska,Z. Ungulate-like mammals from the Late Cretaceous of Uzbekistan and a phylogenetic analysis of Ungulatomorpha. Bull. Carnegie Mus. Nat. Hist. 34, 40–88 (1998).

    Google Scholar 

  5. Ostrom,J. H. Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Montana and Wyoming. Bull. Peabody Mus. Nat. Hist. 35, 1–234 (1970).

    Google Scholar 

  6. Cifelli,R. L. & de Muizon,C. Definition 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 

  7. Butler,P. M. A new interpretation of the mammalian teeth of triposphenic pattern from the Albian of Texas. Breviora 446, 1–27 (1978).

    Google Scholar 

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

    Article  Google Scholar 

  9. Novacek,M. J. The skull of leptictid insectivorans and the higher-level classification of eutherian mammals. Bull. Am. Mus. Nat. Hist. 183, 1–112 (1986).

    Google Scholar 

  10. Sigogneau-Russell,D., Dashzeveg,D. & Russell,D. E. Further data on Prokennalestes (Mammalia, Eutheria inc. sed.) from the Early Cretaceous of Mongolia. Zool. Scripta 21, 205–209 (1992).

    Article  Google Scholar 

  11. Butler,P. M. Early trends in the evolution of tribosphenic molars. Biol. Rev. 65, 529–552 (1990).

    Article  Google Scholar 

  12. Clemens, W. A. Jr & Lillegraven,J. A. New Late Cretaceous, North American advanced therian mammals that fit neither the marsupial nor eutherian molds. Contrib. Geol. Univ. Wyoming 3, 55–85 (1986).

    Google Scholar 

  13. Lillegraven,J. A., Kielan-Jaworowska,Z. & Clemens, W. A. Jr (eds) Mesozoic Mammals—the First Two-thirds of Mammalian History (Univ. of California Press, Berkeley, 1979).

    Google Scholar 

  14. Dashzeveg,D. & Kielan-Jaworowska,Z. The lower jaw of an aegialodontid mammal from the Early Cretaceous of Mongolia. Zool. J. Linn. Soc. 82, 217–227 (1984).

    Article  Google Scholar 

  15. 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 

  16. Nessov,L. A., Sigogneau-Russell,D. & Russell,D. E. A survey of Cretaceous tribosphenic mammals from middle Asia (Uzbekistan, Kazakhstan and Tajikistan), of their geological setting, age and faunal environment. Palaeovert. 23, 51–92 (1994).

    Google Scholar 

  17. Slaughter,B. H. Mid-Cretaceous (Albian) therians of the Butler Farm local fauna, Texas. Zool. J. Linn. Soc. 50 (suppl.), 131–143 (1971).

    Google Scholar 

  18. Wang,Y. Q., Hu, Y.-M., Chow, M.-C. & Li, C.-K. in Sixth Symposium on Mesozoic Terrestrial Ecosystems (eds Sun, A.-L. & Wang, Y.-Q.) 221–228 (China Ocean, Beijing, 1995).

    Google Scholar 

  19. Fox,R. C. Paranyctoides maleficus (new species), an early eutherian mammal from the Cretaceous of Alberta. Spec. Publ. Carnegie Mus. Nat. Hist. 9, 9–20 (1984).

    Google Scholar 

  20. Cifelli,R. L. et al. in Vertebrate Fossils of Utah (ed. Gillette, D. D.) 219–242 (Utah Geological Survey, Salt Lake City, 1999).

    Google Scholar 

  21. Jenkins, F. A. Jr & Schaff,C. R. The Early Cretaceous mammal Gobiconodon (Mammalia, Triconodonta) from the Cloverly Formation in Montana. J. Vert. Paleontol. 8, 1–24 (1988).

    Article  Google Scholar 

  22. Kielan-Jaworowska,Z. Evolution of the therian mammals in the Late Cretaceous of Asia. Part II. Postcranial skeleton in Kennalestes and Asioryctes. Palaeontol. Pol. 37, 65–83 (1974).

    Google Scholar 

  23. Luo,Z. 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 

  24. Luckett,W. P. in Mammal Phylogeny, volume 2—Mesozoic Differentiation, Multituberculates, Monotremes, Early Therians, and Marsupials (eds Szalay, F. S., Novacek, M. J. & McKenna, M. C.) 182–204 (Springer, New York, 1993).

    Google Scholar 

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Acknowledgements

I thank W. D. Maxwell and D. Smith for their collaboration in field activities, S. K. Madsen for fossil preparation, N. J. Czaplewski for illustration, M. Kyte for cooperation of the US BLM, W. Helmer and C. Nomee for the cooperation of the Crow Tribe, and P. Butler for various help. Funding was provided by the National Geographic Society and the NSF.

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  1. Oklahoma Museum of Natural History and Department of Zoology, University of Oklahoma, Norman, 73019, Oklahoma, USA

    Richard L. Cifelli

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Cifelli, R. Tribosphenic mammal from the North American Early Cretaceous. Nature 401, 363–366 (1999). https://doi.org/10.1038/43860

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