Paleontologists working in southern Wyoming have identified a previously unknown species of omomyid primate, adding a new chapter to the story of one of the best-studied fossil lineages in North America. Named Tetonius varleyorum, the animal was comparable in size to a modern mouse lemur. What makes the new discovery of Tetonius varleyorum especially notable is not just the new species itself, but the company it kept. “Our description of Tetonius varleyorum as a new fossil species gives fresh detail to the biogeographic and evolutionary history of primates,” Rhinehart said. A diverse new omomyid primate fauna from the early Eocene of southern Wyoming with implications for interpreting macroevolutionary patterns among anaptomorphines.