A new study was published Feb.24 in the journal Royal Society for Open Science It documents the oldest known fossil evidence of primates.
A team of 10 researchers from across the United States analyzed several fossils of Purgatorius, the oldest genus in a group of the oldest known primates called plesiadapiforms. These ancient mammals were small in body and ate specialized diets of insects and fruits that differed with different species. These newly described specimens are essential for understanding primates’ ancestors and for painting a picture of how life recovered on Earth after the Cretaceous and Paleogene extinction event 66 million years ago that wiped out all dinosaurs – except birds – and led to the emergence of mammals.
Gregory Wilson Mantilla, professor of biology at the University of Washington and curator of vertebrate paleontology at the University of Washington’s Burke Museum of Natural History and Culture, co-led the study with Stephen Chester of Brooklyn College and City University of New York. The team analyzed a fossilized tooth found in the Hill Creek area of northeastern Montana. The fossils, which are now part of the collections in the UCLA Museum of Paleontology, are estimated to be 65.9 million years old, roughly 105,000 to 139,000 years after the mass extinction. Based on the age of the fossils, the team estimates that the ancestors of all primates – including plesiadapiforms and present-day primates such as lemurs, monkeys, and monkeys – likely arose in the late Cretaceous and lived alongside large dinosaurs.
“It’s amazing to think of our early primate ancestors,” said Wilson Mantilla. “It was one of the first mammals to diversify in the new post-mass extinction world, taking advantage of the fruits and insects in the jungle canopy.”
The fossils include two types of Purgatorius: Purgatorius janisae and a new one described by the team called Purgatorius mckeeveri. Three of the found teeth had distinct features compared to any previously known Purgatorius species and led to the description of the new species.
Purgatorius mckeeveri is named after Frank McKeever, who was among the first inhabitants of the area where fossils were discovered, as well as the John and Cathy McKeever family, who have since supported the field work as the oldest specimen of this new species was discovered.
“This was a really great study to be a part of, especially because it provides additional evidence that the earliest primates arose before the extinction of the non-avian dinosaurs,” said co-author Brody Hovatter, a graduate student in Earth and Space Sciences. “It became very abundant within a million years after this extinction.”
“This discovery is exciting because it marks the oldest dated appearance of ancient primates in the fossil record,” said Chester. “It adds to our understanding of how early primates separated from their competitors after the demise of the dinosaurs.”
The late study co-author William Clemens was professor emeritus at the University of California, Berkeley and former director of the University of California Museum of Paleontology. Additional co-authors are Jason Moore and Wade Mannes of the University of New Mexico. Courtney Sprin from the University of Florida. William Mitchell from Minnesota IT Services; Roland Mundell of the Berkeley Geoscience Center; And Paul Wren of the University of California at Berkeley and the Berkeley Geoscience Center. The research was funded by the National Science Foundation, the University of California Paleontology Museum, the Myhrvold and Havranek Family Charitable Fund, UW, CUNY, and the Leakey Foundation.
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Contact: Andrea Godinez
University of Washington, Burke Museum of Natural History and Culture