Peer Review #1 of "The first tetrapod from the mid-Miocene Clarkia lagerstätte (Idaho, USA) (v0.1)"

Abstract

The Clarkia lagerstätte (Latah Formation) of Idaho is well known for its beautifully preserved plant fossils as well as a fauna of insects and fish. Here we present the first known tetrapod fossil from these deposits. This specimen, recovered from the lower anoxic zone of the beds, is preserved as a carbonaceous film of a partial skeleton associated with a partial lower incisor and some tooth fragments. The morphology of the teeth indicates that the first tetrapod reported from Clarkia is a rodent. Its skeletal morphology as well as its bunodont and brachydont dentition suggests that it is a member of the squirrel family (Sciuridae). It is a large specimen that cannot be assigned to a known genus. 18 from these deposits. This specimen, recovered from the lower anoxic zone of the beds, is 19 preserved as a carbonaceous film of a partial skeleton associated with a partial lower incisor and 20 some tooth fragments. The morphology of the teeth indicates that the first tetrapod reported from 21 Clarkia is a rodent. Its skeletal morphology as well as its bunodont and brachydont dentition 22 suggests that it is a member of the squirrel family (Sciuridae). It is a large specimen that cannot 23 be assigned to a known genus. Instead, it appears to represent the first occurrence of a new taxon 24 with particularly gracile postcranial morphology likely indicative of an arboreal ecology. This 25 new specimen is a rare glimpse into the poorly known arboreal mammal fossil record of the 26 Neogene. It supports a greater taxonomic and ecological diversity of Miocene Sciuridae than 27 previously recognized and offers new lines of inquiry in the paleoecological research enabled by 28 the unique preservation conditions of the Clarkia biota.