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

该项目旨在挖掘巴基斯坦中新世Siwalik层序中产量最高的类人族化石。这一地区位于纳格里组的最顶端(距今约900万年)，几乎生产了从西瓦利克人那里发现的西瓦利克人所有头骨后遗骸的一半。与颅骨遗骸不同的是，这些化石几乎没有现存的猩猩Pongo的衍生特征。最新发现的标本是一根肱骨骨干，它与卡特龙的原始状态最相似。很可能西瓦斯库斯缺少一个被普遍认为是现存的类人猿和人类共同衍生的特征，一个中等扭曲的肱骨头部。由于西瓦斯库斯是唯一可信的可以归因于现存类人猿血统的古人类化石，因此对其颅后形态的了解对于检验关于类人猿支系最后一个共同祖先的形态和推断的位置行为的假设至关重要。此前在该地区的发现表明，进一步挖掘出相对完整的西瓦斯库斯后颅骨的可能性很大。

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.