as phylogenetically related to the extant South American seriemas, but these assignments remain controversial. The following cladogram follows the analysis of Degrange and colleagues, 2015: References Phorusrhacinae Bird genera Extinct flightless birds Serravallian extinctions Burdigalian first appearances Miocene birds of South America Laventan Colloncuran Friasian Santacrucian Colhuehuapian Neogene Argentina Fossils of Argentina Fossil taxa described in 1887 Taxa named by Florentino Ameghino