The paleoenvironment of Sivapithecus parvada

Remains of the hominoid Sivapithecus parvada and a diversity of mammalian taxa are preserved at locality Y311 (ca. 10 Ma) in the Siwalik Nagri Formation of northern Pakistan. Bovids (Bovidae, Artiodactyla) are the most abundant mammals next to tragulids (Tragulidae, Artiodactyla) at locality Y311 and provide a means for reconstructing the paleoenvironments that would have been available to Sivapithecus parvada. A functional model indicates a linkage between habitat and several femoral characters among extant bovids. Based on this model, we infer that forested habitats predominated at locality Y311 but that some less densely covered areas may also have been present. Paleoenvironments in the earlier Chinji Formation appear comparable to those at locality Y311, although the presence of a continuous canopy in the former is more certain. Thus, adaptive changes in the bovid fauna from the Chinji through the Nagri Formations appear to have preceded the shift to predominantly C4 grasslands which, based on other lines of evidence, occurred locally (and possibly globally) between 8 and 6 Ma. The paleoenvironments of locality Y311 and the Chinji Formation localities appear different from the paleoenvironment of Kenyapithecus at Fort Ternan in Kenya, where the presence of continuous canopy is unlikely. The Fort Ternan fauna is dominated by two genera of bovids. One of these is adapted to light cover while the other appears better adapted to heavy cover. Sivapithecus and Kenyapithecus lived in different ecological settings probably characterized by varying degrees of vegetative cover.