The Pliocene fossil record is dominated by Old World monkeys and hominins. Pliocene lemur, loris, tarsier, New World monkey, and great ape fossils are nonexistent, and very few fossils of galagos and gibbons have been found. All known Pliocene primate fossils can be assigned to modern families; the sivaladapids and pliopithecids, ancient primate groups that survived into the late Miocene, appear to have gone extinct by the beginning of the Pliocene. Given the patchy nature of the Pliocene fossil record, molecular data have been important in revealing the evolutionary history of modern primate radiations, including speciation and dispersal events that occurred during the Pliocene.
Elton, S. (2017). Pliocene primates. In A. Fuentes (Ed.), The international encyclopedia of primatology. John Wiley and Sons. https://doi.org/10.1002/9781119179313.wbprim0476