期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：1
页码：82-87
DOI：10.1073/pnas.1420275111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThe living apes share a number of important morphological similarities of torso and limbs; torsos are broad and shallow, lumbar regions short, and forelimbs adapted to mobility. For more than a century it was assumed that most of these similarities are homologous, reflecting descent from a common ancestor with these features. As the ape fossil record slowly expands, the story becomes more complicated, particularly in the case of the south Asian Miocene ape Sivapithecus. Sivapithecus has facial features resembling specifically the living orangutan, but no postcranial features resembling orangutans. This newly described hipbone differs from that of all living apes. Either postcranial similarities of apes are not fully homologous or the facial similarities of Sivapithecus and orangutans cannot be homologous. We describe a partial innominate, YGSP 41216, from a 12.3 Ma locality in the Siwalik Group of the Potwar Plateau in Pakistan, assigned to the Middle Miocene ape species Sivapithecus indicus. We investigate the implications of its morphology for reconstructing positional behavior of this ape. Postcranial anatomy of extant catarrhines falls into two distinct groups, particularly for torso shape. To an extent this reflects different although variable and overlapping positional repertoires: pronograde quadrupedalism for cercopithecoids and orthogrady for hominoids. The YGSP innominate (hipbone) is from a primate with a narrow torso, resembling most extant monkeys and differing from the broader torsos of extant apes. Other postcranial material of S. indicus and its younger and similar congener Sivapithecus sivalensis also supports reconstruction of a hominoid with a positional repertoire more similar to the pronograde quadrupedal patterns of most monkeys than to the orthograde patterns of apes. However, Sivapithecus postcranial morphology differs in many details from any extant species. We reconstruct a slow-moving, deliberate, arboreal animal, primarily traveling above supports but also frequently engaging in antipronograde behaviors. There are no obvious synapomorphic postcranial features shared exclusively with any extant crown hominid, including Pongo.
