Late Miocene continental birds from the Cerro Azul Formation in the Pampean region (central-southern Argentina)

Abstract

The oldest known birds from the Cerro Azul Formation are described, including the oldest records for the genera Eudromia and Nothura (Tinamidae), Milvago (Falconidae), Pterocnemia (Rheidae) and an undetermined Tyrannidae. The first remains of Phorusrhacidae for this formation are reported and a specimen previously referred to the giant teratorn Argentavis magnificens is reassigned to this family. We outline and update the current knowledge of the groups studied herein. The palaeornithological record from the Cerro Azul Formation is congruent with palaeoenvironmental inferences previously drawn from mammalian assemblages recovered from this unit, which point to the existence of open environments, possibly xerophyllous shrubby steppes, perhaps with some trees. These records are the first indications of a typically Pampean bird fauna at the end of the late Miocene in central-southern Argentina.