Oligocene Argentina

Psilopterus (Greek for "bare wing") is an extinct genus of phorusrhacid ("terror bird") from the Middle Oligocene to possibly the Late Pleistocene of Argentina and Uruguay. Compared to other phorusrhacids, members of the genus are both relatively gracile and diminutive, and include the smallest known species of terror bird: with the head raised P. bachmanni was in height and weighed about , while the largest members of the genus were only about . The birds resemble the modern cariama (Cariama cristata), except with a heavier build and considerably smaller wings. Fossil finds in Uruguay indicat

Scarrittia is an extinct genus of hoofed mammal of the family Leontiniidae, native to South America during the Late Oligocene epoch (Deseadan in the SALMA classification).

Palaeospheniscus is an extinct genus of penguins belonging to the subfamily Palaeospheniscinae. These penguins are apparently not closely related to the modern genus Spheniscus.