Psilopterus affinis (Ameghino, 1899) Alvarenga, Herculano M. F. & Höfling, Elizabeth, 2003

Alvarenga, Herculano M. F. & Höfling, Elizabeth, 2003, Systematic Revision Of The Phorusrhacidae (Aves: Ralliformes), Papéis Avulsos de Zoologia 43 (4), pp. 55-91 : 83

Psilopterus affinis (Ameghino, 1899) comb. n.

Phororhacos affinis Ameghino, 1899 .

Type – The right tarsometatarsus lacking a segment of diaphysis (MACN-A-52-184).

Hypodigm – Only the type material.

Horizon and Locality – Guaranitica Formation of Patagonia (= Deseado Formation). The Middle to Upper Oligocene of Argentina (Deseadan), Chubut Province: Cabeca Branca.

Measurements – Table 8.

Diagnosis – Small size, rivalling Psilopterus bachmanni . It differs from all the others of the same kind as regards the upper part of the hipotarsus, where a transversal groove separates this from the cotylar surface.

Remarks – Treated as synonymous of Andrewsornis abbotti by Brodkorb (1967), just because it came from the same stratigraphic levels, it differs from this latter by being of a much smaller build. Brodkorb (op. cit.), furthermore, cites the epithet affinis as being pre-occupied by Owenornis affinis Moreno & Mercerat, 1891 , a junior synonymon of Phorusrhacos longissimus , an unfounded concept, seeing that they are perfectly distinct genera. Without doubt, this is the least known species amongst the Phorusrhacidae . It is possible that, with new material and better study, the meagre and insufficient material based whereon Ameghino (1899) decribed other species coming from the “Guaranítica” (Deseadan) Formation of Patagonia, could be clarified: Riacama caliginea , Smiliornis penetrans and Pseudolarus guaraniticus . Some of these could possibly be synonymous with Psilopterus affinis , whereupon to the latter may be added more peculiarites which would justify separating it into a genus apart.