Synonymy and actual affinities of the putative Middle Eocene 'New World vulture' Eocathartes Lambrecht, 1935 and 'hornbill' Geiseloceros Lambrecht, 1935 (Aves, Ameghinornithidae)

摘要

The taxonomy and phylogenetic affinities of the putative "New World vulture" Eocathartes robustus, LAMBRECHT, 1935 and the "hornbill" Geiseloceros robustus LAMBRECHT, 1935 from the Middle Eocene of the Geisel Valley in Germany are revised. It is shown that the holotype specimens belong to a single individual, whose osteology closely resembles that of Strigogyps sapea (PETERS, 1987) from the Middle Eocene of Messel (Germany). The species is classified into Strigogyps robustus (LAMBRECHT, 1935), n. comb., and provides further evidence for the great similarity between the Eocene avifaunas of the Geisel Valley and Messel. Strigogyps is a representative of the Ameghinornithidae whose phylogenetic affinities are uncertain; there is no fossil record of either Cathartidae (New World vultures) or Bucerotidae (hornbills) from the Geisel Valley.