La posición sistemática de Hermosiornis (Aves, Phororhacoidea) y sus implicancias filogenéticas

Abstract

The systematic position of Hermosiornis (Aves, Phororhacoidea) and its phylogenetic implicances.
In the present contribution, the phylogenetic relationships of Hermosiornis within the Phororhacoidea
are re-evaluated. This taxon is here considered as the sister-group of the clade Phorusrhacidae, on the basis of
unambiguous synapomorphies including very short forearm, III metatrsal trochlea subrectangular in contour,
and several features of the carpometacarpus. The new clade Hermosiornis + Phorusrhacidae is here termed as
Neorhaci nov. The increment in body size, the extreme reduction of the forelimbs and its consequent flightless capabilities,
as well as the deep elongation of hindlimbs may be features acquired at the base of Neorhaci. Moreover,
a detailed analysis of the synapomorphies previously employed in order to ally Hermosiornis with Psilopteridae,
are here considered as plesiomorphic for Phororhacoidea. Moreover, several aspects regarding phororhacoid nomenclature,
previous phylegenetic analysis, and some detailes of the anatomy of Hermosiornis are analyzed.
Finally, several putative post-Pliocene records of Phororhacoidea are criticized, and are considered dubious, at
least. In this way, the biochron of Phororhacoidea is considered as Lower Eocene-Pliocene.