Wyoming Fossils Reveal 55-Million-Year-Old Primate Species, Complicating Early Evolution
Updated
Updated · Cowboy State Daily · Aug 15
Wyoming Fossils Reveal 55-Million-Year-Old Primate Species, Complicating Early Evolution
1 articles · Updated · Cowboy State Daily · Aug 15
Summary
A Journal of Human Evolution study reports 55-million-year-old primate fossils from Smiley Draw in southwestern Wyoming, including a new Tetonius species, T. varleyorum.
The sandstone site also yielded Arapahovius gazini and Anemorhysis savage together, a combination not seen in Wyoming’s better-studied Bighorn Basin, suggesting local extinction and evolution patterns were more complex than thought.
Jaw and tooth anatomy indicates T. varleyorum followed a parallel evolutionary path—shorter jaws, fewer teeth and enlarged incisors—similar to but distinct from Tetonius lineages known from the Bighorn Basin.
Researchers say repeated Eocene hyperthermal warming and cooling may explain why primates coexisted in Sweetwater County after related lineages had disappeared elsewhere in Wyoming.
Chris Beard said new fossils collected at Smiley Draw in June are already under micro-CT study, pointing to more discoveries from a region he called central to understanding early primate evolution.