Three New Early Middle Eocene Bats (Mammalia: Chiroptera) from Elderberry Canyon, Nevada, USA

Abstract

We report three new taxa of bats from the late early Eocene to earliest middle Eocene (Bridgerian biochrons Br1b–Br2; ca. 50–48 Ma) Elderberry Canyon Quarry, Sheep Pass Formation, in the Egan Mountain Range of eastern Nevada, USA. Volactrix simmonsae gen. et sp. nov., represented by two dentaries, is tentatively referred to the family ?Onychonycteridae and exhibits a p3 that is much smaller than the p2, a semimolariform p4, and lower molars with a postcristid configuration intermediate between necromantodonty and nyctalodonty. The genus Palaeochiropteryx, a palaeochiropterygid otherwise known from the early and middle Eocene of Europe, is the first representative of its genus and of the family Palaeochiropterygidae outside Eurasia and the Indo-Pakistan subcontinent. Palaeochiropteryx is represented at the site by a partial skeleton with a crushed skull and two left dentaries (one unexposed within the same limestone block but revealed by micro-computed tomography scanning) and is formally named Palaeochiropteryx sambuceus sp. nov. A third taxon, Sonor handae gen. et sp. nov., is a probable vespertilionid, evidenced by a dentary fragment with double-rooted p3 and myotodont lower molar morphology, and provides the earliest occurrence of the family Vespertilionidae in the Western Hemisphere. Despite the small number of specimens, these three new taxa comprise the most diverse Eocene assemblage of bats yet found in a single quarry in the Western Hemisphere.