Argentavis

Argentavis is an extinct genus of teratornids known from three sites in the Epecuén and Andalhualá Formations in central and northwestern Argentina dating to the Late Miocene (Huayquerian), where a good sample of fossils has been obtained. The type species, A. magnificens, is sometimes called the giant teratorn. It was among the largest flying birds ever to exist. While it is still considered the heaviest flying bird of all time, Argentavis was likely surpassed in wingspan by Pelagornis sandersi which is estimated to have possessed wings some 20% longer than Argentavis and which was described in 2014.