An Eocene New World vulture (Aves, Cathartidae) from Mongolia

Abstract

New World vultures (Aves, Cathartidae) are a group of large diurnal birds of prey, currently restricted to the Americas. The early evolutionary history of New World vultures is poorly known, with the oldest unambiguous members of this phylogenetic lineage having been described from the Eocene of Europe. A single putative cathartid from Asia was mentioned in brief in 1985, but until now remained unillustrated and unstudied. This paper describes for the first time this find, a partial tarsometatarsus from the upper Eocene of the Ergilin Dzo Formation in Eastern Mongolia, as a new taxon Gobicathartes prodigialipes gen. et sp. nov., which is the second oldest known member of this evolutionary lineage. It was a large bird (comparable to the extant King Vulture in size), morphologically most similar to the living non-condor Cathartidae, but clearly distinct from the fossil European forms. It demonstrates the wide Eurasian distribution of members of the New World vulture lineage in the Eocene of Eurasia and supports an out-of-Asia dispersal of ancestral Cathartidae to the Americas.