title: The last fossil primate in North America, new material of the enigmatic Ekgmowechashala from the Arikareean of Oregon.
abstract: OBJECTIVE
  Primates were common in North America through most of the Eocene, but vanished in the Chadronian, about 35 million years ago. In the Arikareean, about 6 million years later, the enigmatic primate Ekgmowechashala appeared in the Great Plains and Oregon. This taxon shows little resemblance to other North American primates and its phylogenetic position has long been debated. New material of this taxon allows a revised assessment of its age and how it is related to other primates.
  
  
  METHODS
  Recently collected Ekgmowechashala specimens from the Turtle Cove Member of the John Day Formation in Oregon are described. These specimens are compared to previously collected material from South Dakota and Nebraska, as well as other fossil primates from North America and Asia.
  
  
  RESULTS
  Study of the John Day material allows diagnosis of a new, distinct species. Comparison of Ekgmowechashala to a pair of recently described Asian primates, Muangthanhinius and Bugtilemur, suggests that it is a strepsirrhine adapiform, rather than an omomyid. The well-defined stratigraphy and dated marker beds of the Turtle Cove Member provide a refined age for Ekgmowechashala occurrences in Oregon, during the Oligocene (early Arikareean).
  
  
  CONCLUSIONS
  The age and morphology of these ekgmowechashaline taxa suggest that the group originated in Asia and dispersed to North America in the Oligocene, after the extinction of other primates in North America. Contemporaneous occurrences of Ekgmowechashala in Oregon and the Great Plains indicate the last non-human primates vanished in North America about 26 million years ago.
authors.affiliation: National Park Service, John Day Fossil Beds National Monument, Kimberly, OR, 97848.
authors.forename: Joshua X
authors.initials: JX
authors.lastname: Samuels
authors.affiliation: Department of Physics, University of North Florida, Jacksonville, FL, 32224.
authors.forename: L Barry
authors.initials: LB
authors.lastname: Albright
authors.affiliation: National Park Service, John Day Fossil Beds National Monument, Kimberly, OR, 97848.|Department of Geological Sciences, Museum of Natural and Cultural History, University of Oregon, Eugene, OR, 97403.
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Fremd
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005075:Biological Evolution; D005580:Fossils; D009922:Oregon; D011323:Primates / Q000033:anatomy & histology* / Q000502:physiology*; D014070:Tooth / Q000033:anatomy & histology*
keywords: Adapiformes; Ekgmowechashalinae; John Day Formation