Department of Anthropology, Boston University, Boston, MA 02215, USA.
J Hum Evol. 2010 Feb;58(2):147-54. doi: 10.1016/j.jhevol.2009.11.002. Epub 2009 Dec 29.
A distal tibia, YGSP 1656, from the early Late Miocene portion of the Chinji Formation in Pakistan is described. The fossil is 11.4 million years old and is one of only six postcranial elements now assigned to Sivapithecus indicus. Aspects of the articular surface are cercopithecoid-like, suggesting some pronograde locomotor activities. However, YGSP 1656 possesses an anteroposteriorly compressed metaphysis and a mediolaterally thick medial malleolus, ape-like features functionally related to orthograde body postures and vertical climbing. YGSP 1656 lacks specializations found in the ankle of terrestrial cercopithecoids and thus Sivapithecus may have been primarily arboreal. Nevertheless, the morphology of this tibia is unique, consistent with other interpretations of Sivapithecus postcranial functional morphology that suggest the locomotion of this ape lacks a modern analog. Based on the limited postcranial remains from S. indicus, we hypothesize that this taxon exhibited substantial body size dimorphism.
描述了一块来自巴基斯坦钦吉组晚期中新世部分的远端胫骨，编号为 YGSP 1656。这块化石已有 1140 万年的历史，是目前唯一被归入印度古猿的 6 块后肢骨骼之一。关节面的某些方面与猕猴相似，表明其具有一定的前倾运动活动。然而，YGSP 1656 具有前后压缩的骨干和内外侧厚的内踝，这些特征类似于猿类，与垂直姿势和垂直攀爬有关。YGSP 1656 缺乏在地面猕猴的踝关节中发现的特化结构，因此印度古猿可能主要是树栖的。然而，这块胫骨的形态是独特的，与其他对印度古猿后肢功能形态的解释一致，表明这种猿类的运动方式缺乏现代类似物。根据来自印度古猿的有限的后肢遗骸，我们假设该类群表现出明显的体型二态性。
