Named By: Francisco P. Moreno & Alcides Mercerat - 1891.
Synonyms: Patagornis bachmanni, P. lemoinei, Pelecyornis tubulatus, Phororhacos delicatus, P. modicus, Psilopterus australis, P. communis, P. intermedius - *note, other synonyms may actually exist and this list should not be assumed to be complete.
Classification: Chordata, Aves, Cariamae, Phorusrhacidae, Psilopterinae.
Species: P. bachmani (type), P. affinis, P. colzecus, P. lemoinei.
Size: From 70-80 centimetres, up to just under a metre tall, depending upon species. Weight estimated between 5 and 7 kilograms, again depending upon the size of the species.
Known locations: Argentina.
Time period: Mid Oligocene through to late Miocene.
Fossil representation: Many specimens, but often of fragmentary remains.
one of the smallest members of the Phorusrhacidae, Psilopterus
way near the scale of the larger phorusrhacids like Brontornis.
However the exact size of Psilopterus is something
that is hard to be
certain about as not only do estimates depend upon the specific
species, but there is an outside chance that material referred to the
smallest (P. bachmani) and largest (P.
may actually represent the same genus. Clarification of this matter
is not helped by the fact that most Psilopterus
remains are of
fragmentary fossil material, a problem caused by the hollow light
weight bones typical to birds that get damaged easily during
fossilization. Also many of the species once assigned to Psilopterus
have now be found to represent other older species, as well as
additional material from other genera being reassigned to Psilopterus
The ‘terror bids’ of the Phorusrhacidae are often compared to the extant seriema birds of South America (Cariama cristata and Chunga burmeisteri), and out of all the phorusrhacids, Psilopterus is closest to the seriema in physical size. This would suggest similar hunting behaviour where Psilopterus’s preferred prey would be invertebrates such as large insects and small vertebrates like lizards, frogs and small rodents. Psilopterus may have also had a similar feeding style where small prey would be thrown against the ground and hard objects to stun and kill the prey as well as break its bones for easier swallowing. The long legs of Psilopterus would have allowed it to peer down into the undergrowth from above where prey could be more easily spotted, as well as providing a good turn of speed for avoiding other larger predators.