Protopithecus


Protopithecus is an extinct genus of large New World monkey that lived during the Pleistocene. Fossils have been found in the Toca da Boa Vista cave of Brazil, as well as other locales in the country. Fossils of another, less robust, large ateline monkey, Caipora, were also discovered in Toca da Boa Vista.

Description and paleobiology

At an estimated weight of, it was the largest New World monkey known to exist. With slightly longer arms than legs, Protopithecus resembled spider monkeys, but its limb bones were nearly twice as thick. Its head was more similar to a howler monkey's, which has a lower jaw that juts forward to accommodate an apple-size vocal sac. As such, Protopithecus may have been able to howl just like them.
Although its large size has led to the suggestion that it may have been partially or primarily terrestrial, Halenar found no adaptations to terrestrial locomotion in the skeleton of Protopithecus, which has a morphology characteristic of arboreal monkeys, although given its estimated weight, it is unlikely to have been a suspensory feeder like Ateles and Brachyteles. It may have been an arboreal quadruped which made occasional use of the ground, comparable to a great ape or the larger subfossil lemurs.
Although closely related, howler and spider monkeys split from their common ancestor long before Protopithecus evolved. This means that the distinctive features of these modern monkeys have evolved more than once.

Paleoecology

Other animals found in Toca da Boa Vista include another large atelid, Caipora bambuiorum, as well as Arctotherium brasiliensis, Catonyx cuvieri, Desmodus draculae, Nothrotherium maquinense, Protocyon troglodytes, Smilodon populator, giant anteaters, collared peccaries, crab-eating foxes and raccoons, striped hog-nosed skunks, and guanacoes.
The environment inhabited by Protopithecus is unclear. Most of Brazil was thought to have been covered in open tropical cerrado vegetation during the Late Pleistocene, but if Protopithecus and Caipora were arboreal, their presence suggests that the region may have supported a dense closed forest during the Late Pleistocene. It is possible that the region alternated between dry open savannah and closed wet forest throughout the climate change of the Late Pleistocene.