1Anthropology, The University of Texas at Austin, 2Anthropology, Western Michigan University, 3Vertebrate Paleontology, Carnegie Museum of Natural History, 4Applied Geology, Curtin University
Thursday 8:30-8:45, Ballroom C
Fieldwork in early Eocene deposits of the Great Divide Basin (GDB), Wyoming, has uncovered a significant new fossil locality (WMU-VP-2009-01) preserving a diverse mammalian fauna. This fauna includes at least four primate taxa. Notably, the primate fauna is dominated by small-bodied omomyids, rather than the larger adapids that typify most of the Wasatchian localities within the GDB. The quality of the fossils is unique for the GDB, exhibiting excellent preservation, with most jaws including 3-5 teeth. Similar to the primates, the remainder of the mammalian assemblage is likewise dominated by small-bodied morphs that are normally rare within GDB localities. The geology of the locality suggests that the unique faunal composition and associated preservation could represent an environment characterized by high energy flooding and rapid deposition.
The locality has been dated biostratigraphically, in part based on the recovery of a nearly complete hemi mandible of the omomyid, Tetonius matthewi. This fossil is morphologically identical to the Stage 2 transitional morphotype within the proposed Tetonius-Pseudotetonius lineage. Correlation of this fossil with the well-dated faunal sequence in the nearby Bighorn Basin demonstrates that this GDB locality is temporally located near the base of Wa-4. While only one adapid (Cantius mckennai) has been recovered from WMU-VP-2009-01, two additional omomyid taxa are present, including a probable new species of Anemorhysis and an enigmatic new species that exhibits morphological affinities with later occurring omomyines. These taxa mark WMU-VP-2009-01 as one of the most diverse omomyid localities within the Wa-4 biochron.