More than 40 million years ago, primates preferred Texas to northern climates that were significantly cooling, according to new fossil evidence discovered by Chris Kirk, physical anthropologist at The University of Texas at Austin.
Kirk and Blythe Williams from Duke University have discovered Diablomomys dalquesti, a new genus and species of primate that dates to 44-43 million years ago when tropical forests and active volcanoes covered west Texas.
During the early part of the Eocene epoch, primates were common in the tropical forests that covered most of North America. Over time, however, climatic cooling caused a dramatic decline in the abundance and diversity of North American primates. By the end of the Eocene, primates and most tropical species had almost disappeared from North America.
Kirk's discovery of late middle Eocene (Uintan) primates at the Devil's Graveyard Formation in Southwest Texas reveals new information about how North American primates evolved during this period of faunal (animal) reorganization.
"After several years of collecting new fossils, reviewing Texas' primate community and comparing it to other places in North America, we found a much more diverse group of primate species in Texas than we expected," Kirk said. "It seems that primates stuck around in Texas much longer than many other parts of the continent because the climate stayed warm for a longer period of time. While primate diversity was falling off precipitously in places like Utah and Wyoming during the late middle Eocene, west Texas provided a humid, tropical refuge for primates and other arboreal (tree-inhabiting) animals."
The anthropologists named the new primate Diablomomys dalquesti, combining "Diablo" to represent the Devil's Graveyard Formation (sand- and mudstones near Big Bend National Park) with Omomys, a related fossil genus. The dalquesti species name honors Walter and Rose Dalquest, who donated the land on which the fossil was collected (Midwestern State University's "Dalquest Research Site"). Walter was a Texas paleontologist and distinguished biology professor at Midwestern State University in Wichita Falls until his death in 2000.
- Williams et al. New Uintan primates from Texas and their implications for North American patterns of species richness during the Eocene. Journal of Human Evolution, October 2008; DOI: 10.1016/j.jhevol.2008.07.007
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