A new Old World vulture from the late Miocene of China sheds light on Neogene shifts in the past diversity and distribution of the Gypaetinae

摘要

Neogene fossils of Old World vultures (Aegypiinae and Gypaetinae) are known from both Old World and New World records. There are no extant Old World vultures in the Americas today, although a large diversity of Gypaetinae is known from Miocene to late Pleistocene records. Despite a comparatively large number of North American gypaetine fossils, complete specimens have rarely been reported from Eurasia and Africa. We describe the exceptional skeleton of a new gypaetine vulture from the late Miocene deposits of the Linxia Basin in northwestern China. The specimen is the oldest record of Gypaetinae from Eurasia or Africa. A reexamination of the geographic and temporal distribution of most Old World vultures from Neogene deposits indicates a diverse radiation, coincident with early- to mid-Miocene grassland expansion for Gypaetinae. Although the diversification of Aegypiinae has been linked to the transition from C-3 to C-4 grassland, Gypaetinae diversification predates that transition in both North America and Asia. A shift in the known latitudinal distribution is also noted. Neogene records of Old World vultures are found primarily in mid- and high-latitude regions of North America and Eurasia as well as in the middle and low latitudes of Eurasia and Africa. With very few records in the middle to late Miocene, a latitudinal distribution similar to that of extant species is first seen in the early Pliocene. The new fossil provides further temporal constraints on avian subclade diversification. It is also consistent with an emerging pattern of profound recent shifts in avian diversity and distribution more generally.