Psilopterus is an extinct genus of phorusrhacid 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 70–80 centimeters (2.3–2.6 ft) in height and weighed about 5 kilograms (11 lb), while the largest members of the genus were only about 8 kilograms (18 lb). The birds resemble the modern cariama, except with a heavier build and considerably smaller wings. Fossil finds in Uruguay indicate the genus may have survived until 96,040 ± 6,300 years ago, millions of years after the larger phorusrhacids became extinct.

Llallawavis scagliai is a large, extinct predatory bird from Pliocene Argentina. Its fossil is the most complete fossil of a phorusrhacid yet found.