Excavation of a Hominoid Locality in the Miocene Siwalik Sequence of Pakistan

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This project is to excavate the most productive hominoid- bearing locality in the Miocene Siwalik sequence of Pakistan. This locality, in the uppermost Nagri Formation (ca. 9 million years old), has produced almost half of all the postcranial remains of Sivapithecus recovered from the Siwaliks. Unlike the cranial remains, these show few if any of the derived features of the extant orang-utan, Pongo. The most recently recovered specimen, a humeral diaphysis, is most similar to what can be presumed to be the primitive condition for catarrhines. It may well be that Sivapithecus lacked a feature that is universally considered to be a shared derived feature of the extant great apes and humans, a medially torsioned humeral head. As Sivapithecus is the only fossil hominoid that can plausibly be placed on the lineage of one of the extant apes, knowledge of its postcranial morphology is critical for testing assumptions about the morphology and inferred positional behaviors of the last common ancestor of the hominoid clade. Previous recoveries from this locality indicate that the probability of excavating further, relatively complete postcranial elements of Sivapithecus is good.