First reported fossil occurrences of Phrynosoma sp. from the Columbia Plateau (Washington State, USA) dated to the Late Pleistocene

Abstract

Reptiles, squamates in particular, can be extremely valuable as indicator species due to their commonly small fundamental niche ranges. Yet these taxa are often overlooked in North American Cenozoic palaeoecological studies in favour of mammalian specimens. At the Coyote Canyon Mammoth Site (CCMS) on the Columbia Plateau (eastern Washington State, USA) excavation has focused on the collection and subsequent identification of all diagnostic fossil specimens, whether associated directly with the mammoth remains or not, including small non-mammalian vertebrates and invertebrates. Here we show that with appropriate excavation techniques, microvertebrate fossils are recoverable and can be identified to at least the genus level. We place the identification of two fossils of Phrynosoma at the CCMS, dated to ~13 and 15 ka, in the context of all recorded fossils identified to this genus in North America since the Middle Miocene. These specimens represent the first fossils of Phrynosoma adequately described and reported from the Columbia Plateau and the greater Pacific Northwest.