Phorusrhacos

Phorusrhacos Temporal range: Early-Mid Miocene (Colhuehuapian-Laventan)
Reconstructed skull, Royal Ontario Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Cariamiformes
Family:	†Phorusrhacidae
Subfamily:	†Phorusrhacinae
Genus:	†Phorusrhacos Ameghino 1887
Type species
†Phorusrhacos longissimus Ameghino 1887
Synonyms
Genus synonymy Phororhacos Ameghino 1889 Stereornis Moreno & Mercerat 1891 Darwinornis Moreno & Mercerat 1891 Owenornis Moreno & Mercerat 1891 Titanornis Mercerat 1893 Callornis Ameghino 1895 Liornis Ameghino 1895 Eucallornis Ameghino 1901 Species synonymy Phororhacos longissimus Ameghino 1889 Stereornis rollieri Moreno & Mercerat 1891 Stereornis gaundryi Moreno & Mercerat 1891 Mesembriornis studeri Moreno & Mercerat 1891 Mesembriornis quatrefragesi Moreno & Mercerat 1891 Darwinornis copei Moreno & Mercerat 1891 Darwinornis zittelli Moreno & Mercerat 1891 Darwinornis socialis Moreno & Mercerat 1891 Owenornis affinis Moreno & Mercerat 1891 Owenornis lydekkeri Moreno & Mercerat 1891 Phororhacos sehuensis Ameghino 1891 Phororhacos platygnathus Ameghino 1891 Titanornis mirabilis Mercerat 1893 Callornis giganteus Ameghino 1895 Liornis floweri Ameghino 1895 Eucallornis giganteus Ameghino 1901 Liornis minor Dolgopol de Saez 1927

Phorusrhacos (/ˌfɔːrəsˈrɑːkɒs/ FOR-əs-RAH-koss) is an extinct genus of giant flightless terror birds that lived in Miocene Patagonia. The type species is P. longissimus. The closest living relatives of P. longissimus are the much smaller seriemas. It is thought to have lived in woodlands and grasslands.

Phorusrhacos grew up to 2.5 metres (8.2 ft) tall and weighed approximately 130 kilograms (290 lb). They had large skulls, up to sixty centimetres (24 in) long, armed with powerful, hook-tipped beaks. The structure of the beak and the large claws on the toes show that they were carnivorous.

Discovery

Restoration by Charles R. Knight, 1901

Size comparison of Phorusrhacos to other predatory flightless birds

Among the bones found in the strata of the Santa Cruz Formation (now considered as mainly of mid-Miocene date) was the piece of a mandible which Florentino Ameghino discovered in early 1887 and the same year at first described as that of an edentate mammal which he named Phorusrhacos longissimus. The generic name is derived from Greek -φόρος, (-phoros), an element meaning "bearer" in word combinations, and ῥάκος, (rhakos), "rag" or "wrinkle", probably in reference to the wrinkled jaw surface. When the original derivation was no longer understood, other translations were given, such as the literal translation of "Rag-Thief", and "branch-holder" from the mistaken assumption the name had been intended to be derived from a Greek rhakis, "branch". The specific name means "very long" in Latin, again in reference to the lower jaws. The holotype is the mandible, specimen MLP-118 (Museo de La Plata). In 1889 Ameghino emended the name to a more grammatically correct Phororhacos but the earlier name has priority. In 1891, it was by him recognized to be a bird. Remains are known from several localities in the Santa Cruz and Monte León Formations in the Santa Cruz Province, of Argentina.