A complete skeleton of the giant South American primate Protopithecus

Abstract

A COMPLETE skeleton of a large-bodied New World monkey has been found in Pleistocene cave deposits in the Brazilian state of Bahia. It demonstrates an unprecedented combination of body size, locomotor and cranial morphology. Skeletal features indicate an animal of approximately 25 kg, more than twice the mass of any living South American monkey. We refer the specimen to Protopithecus brasiliensis Lund, 1838, a large Pleistocene primate originally represented by only a proximal femur and distal humerus^1–4. The skeleton resembles species of two distinct New World monkey lineages. The cranium is modified for an enlarged vocal sac typical of living howler monkeys^5–7, and the postcranium includes suspensory and brachiating components of locomotion as seen in living spider and woolly spider monkeys⁸. This skeleton confirms that adaptive diversity in neotropical primates was greater in the recent past, and that current interpretations of how their distinctive adaptations evolved should be revised.