Phorusrhacid

Phorusrhacids Temporal range: Late Paleocene - ,62–1.8 Ma PreЄ Є O S D C P T J K Pg N
Reconstructed skeleton of Titanis walleri, Florida Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Cariamiformes
Superfamily:	†Phorusrhacoidea Ameghino, 1889
Family:	†Phorusrhacidae Ameghino, 1889
Type species
†Phorusrhacos longissimus Ameghino, 1887
Subfamilies
†Brontornithinae †Mesembriornithinae †Patagornithinae †Phorusrhacinae †Psilopterinae
Synonyms
Family synonymy Pelecyornidae Ameghino, 1891 Brontornithidae Moreno & Mercerat, 1891 Darwinornithidae Moreno & Mercerat, 1891 Stereornithidae Moreno & Mercerat, 1891 Patagornithidae Mercerat, 1897 Hermosiornidae Rovereto, 1914 Psilopteridae Dolgopol de Saez, 1927 Devincenziidae Kraglievich, 1932 Mesembriorniidae Kraglievich, 1932

†Brontornithinae
†Mesembriornithinae
†Patagornithinae
†Phorusrhacinae
†Psilopterinae

Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were the largest species of apex predators in South America during the Cenozoic era; their temporal range covers from 62 to 1.8 million years (Ma) ago.

They ranged in height from 1–3 metres (3.3–9.8 ft) tall. Their closest modern-day relatives are believed to be the 80 cm-tall seriemas. Titanis walleri, one of the larger species, is known from Texas and Florida in North America. This makes the phorusrhacids the only known large South American predator to migrate north in the Great American Interchange that followed the formation of the Isthmus of Panama land bridge (the main pulse of the interchange began about 2.6 Ma ago; Titanis at 5 Ma was an early northward migrant).

It was once believed that T. walleri became extinct in North America around the time of the arrival of humans, but subsequent datings of Titanis fossils provided no evidence for their survival after 1.8 Ma. Still, reports from Uruguay of new findings dating to 450,000 and 17,000 years ago, would imply that some phorusrhacids survived there until very recently (i.e., until the late Pleistocene); but this claim is debated.