Vertebrate Paleontology

Former Curator and Mary R. Dawson Chair of Vertebrate Paleontology K. Christopher Beard

Mammal Evolution Across the Paleocene–Eocene Boundary 

 

bigmulti 

A Carnegie Museum field crew working at Big Multi Quarry
in southwestern Wyoming in 1993.

 

Two current field projects of Carnegie Museum of Natural History aim to help fill in gaps in our knowledge of Clarkforkian and early Wasatchian mammals in North America. Since 1992 field crews from Carnegie Museum have worked at the early Clarkforkian Big Multi Quarry in the northern Washakie Basin, Sweetwater County, Wyoming. The mammalian fauna obtained from this unique site is adding a great deal to our understanding of mammal diversity in the early Clarkforkian. Numerous taxa from Big Multi Quarry are new. Others are documented by extraordinarily complete fossils which reveal anatomical details that were previously unknown, thereby clarifying phylogenetic relationships. Rarely documented plant/animal associations are founded on a well-preserved fossil flora, which occurs a few inches above the mammal-producing horizon.

The first diverse Wasatchian mammal fauna from eastern North America has been recovered from the Tuscahoma Formation in east-central Mississippi by field parties from Carnegie Museum since 1990. Screen washing has yielded some 250 mammal teeth, including those of rodents, omomyid primates, insectivores, and many other taxa. This mammal fauna occurs in estuarine facies and is associated with sharks, rays, snakes, lizards, bony fishes, dinoflagellates, and pollen. Correlation with marine biochronologies suggests that the immigration of basal Wasatchian mammals into North America was virtually synchronous with the immigration of similar forms in the basal Sparnacian of western Europe.

Further exploration of early Cenozoic basins in China will yield additional insight regarding the biogeographic role of Asia in early primate evolution. We hope to address the issues of primate origins, tarsier phylogeny and biogeography, and the evolutionary history of other Eocene primate clades over the next several years.

Our field and laboratory research has been funded by the National Science Foundation, the National Geographic Society, the L. S. B. Leakey Foundation, and Carnegie Museum of Natural History.

Intercontinental Correlation of Paleogene Mammalian Faunas 

Beard, K. C., M. R. Dawson, andA. Tabrum 
Vertebrate Paleontology
Carnegie Museum of Natural History
 

The latest Paleocene and earliest Eocene were times of major faunal turnover in the mammalian fossil record. Origins of modern mammalian orders were accompanied by climatic changes from a cool Paleocene to a warm Eocene. More precise intercontinental correlation of the mammalian faunas is crucial for the studies of phylogenetic evolution and paleobiogeography of mammals during the Paleocene–Eocene transition. Field studies in Mississippi, Wyoming, and China, using biostratigraphic and other methods, are aimed to refine the correlation of the mammalian faunas on a global scale, especially between North America and Asia.

Reference: Beard, K. C., M. R. Dawson, and A. R. Tabrum. 1995. First diverse land mammal fauna from the Early Cenozoic of the southeastern United States: The Early Wasatchian Red Hot local fauna, Lauderdale County, Mississippi. Geological Society of America, Abstracts with Programs, 1995:A-453.

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