Abstract

The fossil bird Dryornis pampeanus Moreno and Mercerat, is reinterpreted after examination of new referred material (humerus, coracoid, fragments of ulna, radius, scapula, sternum and tibiotarsus) coming from the Pliocene Chapadmalal Formation of Argentina. The current diagnosis is emended in the light of important considerations that cast out doubts on previous attribution of the taxon to condors. Phylogenetic position of Dryornis pampeanus was tested in a series of maximum parsimony analyses including all seven living Cathartiformes and 207 osteological characters. Our phylogenetic analyses placed Dryornis pampeanus as the sister taxon of extant vultures. Mass estimation of 26 kilograms positions Dryornis pampeanus as the largest cathartiform ever lived. The presence of this taxon in both the Monte Hermoso and Chapadmalal formations not only extends the stratigraphic range of the species, but also supports the idea that they were partially contemporaneous during the early Pliocene. The dependence of the vultures on ephemeral carrion suggests that they have especially large ranges. The site from which the lectotype (Monte Hermoso) was recovered and that of the new findings (Chapadmalal) are only 400 km away suggesting that both sites could be part of the species distribution.