Psilopterus fossil map
Where fossils of Psilopterus have been found, shown on the Earth as it looked about 15 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 15 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →

| Group | Prehistoric birds |
|---|---|
| Lived | 23.04–0.0117 million years ago (Aquitanian to Late Pleistocene) |
| Periods | Neogene, Quaternary |
| Family | Phorusrhacidae |
| Named by | Moreno and Mercerat 1891 |
| Fossil records | 28 occurrences at 20 locations (PBDB) |
| Found in | Argentina, Uruguay |
| Rock formations | Santa Cruz, Arroyo Chasicó, Monte Leon, Dolores, Cerro Boleadoras |
About Psilopterus
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 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 (Cariama cristata), 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.
Text in “About” is quoted from the Wikipedia article Psilopterus (revision 1325190637), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q2468395.