to nuclear sequence studies, are a clade consisting of Falconidae, Psittaciformes and Passeriformes. The following cladogram follows the analysis of Degrange and colleagues, 2015: References External links Hooper Museum Terror Birds: Bigger and Faster (Science) Darren Naish: Tetrapod Zoology: "terror birds" Darren Naish: Tetrapod Zoology: "Raven, the claw-handed bird, last of the phorusrhacids" includes links to other articles on phorusrhacids Extinct flightless birds Danian first appearances Pleistocene extinctions Apex predators Cenozoic birds of South America Taxa named by Florentino Ameghino Prehistoric bird families