Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA.
Department of Anthropology, Graduate Center, City University of New York, New York, NY 10016, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA.
J Hum Evol. 2018 May;118:27-42. doi: 10.1016/j.jhevol.2018.02.005. Epub 2018 Mar 5.
Detailed analyses and comparisons of postcranial specimens of Plio-Pleistocene cercopithecids provide an opportunity to examine the recent evolutionary history and locomotor diversity in Old World monkeys. Studies examining the positional behavior and substrate preferences of fossil cercopithecids are also important for reconstructing the paleoenvironments of Plio-Pleistocene hominin sites. Here we describe a new fossil cercopithecid tibia (EP 1100/12) from the Australopithecus afarensis-bearing Upper Laetolil Beds (∼3.7 Ma) of Laetoli in northern Tanzania. The fossil tibia is attributed to cf. Rhinocolobus sp., which is the most common colobine at Laetoli. In addition to qualitative comparisons, the tibial shape of EP 1100/12 was compared to that of 190 extant cercopithecids using three-dimensional landmarks. Discriminant function analyses of the shape data were used to assess taxonomic affinity and shape variation relating to positional behavior. EP 1100/12 clustered with extant colobines, particularly the large-bodied genera Nasalis and Rhinopithecus. Comparisons reveal that EP 1100/12 belongs to a large-bodied monkey that engaged in arboreal pronograde quadrupedalism. These findings add further support to previous inferences that woodland and forest environments dominated the paleoenvironment of the Upper Laetolil Beds, which supported the diverse community of cercopithecids at Laetoli. The inferred paleoecology and the presence of large-bodied arboreally-adapted monkeys at Laetoli show that A. afarensis had access to a range of diverse habitats, including woodlands and forests. This supports the possibility that A. afarensis, with its potential range of positional capabilities, was able to utilize arboreal settings for food acquisition and refuge from predators.
详细分析和比较更新世至更新世灵长类动物的后肢骨骼标本，为研究旧世界猴的近期进化历史和运动多样性提供了机会。研究化石长尾猴的姿势行为和基质偏好对于重建更新世人类遗址的古环境也很重要。本文描述了一件来自坦桑尼亚北部拉托利地层（约 370 万年前）的南方古猿阿法种化石长尾猴的新胫骨（EP 1100/12）。这块化石胫骨被归入 Rhinocolobus sp.，这是拉托利最常见的疣猴科动物。除了定性比较外，还使用三维标志对 EP 1100/12 的胫骨形状与 190 种现存的长尾猴进行了比较。使用形状数据的判别函数分析来评估分类亲和力和与姿势行为相关的形状变化。EP 1100/12 与现生的疣猴科动物聚类在一起，特别是大型的 Nasisalis 和 Rhinopithecus 属。比较结果表明，EP 1100/12 属于一种大型猴子，它采用树栖性前向四足行走姿势。这些发现进一步支持了先前的推断，即林地和森林环境主导了拉托利上层的古环境，这支持了拉托利多样化的长尾猴群落。推断出的古生态学和拉托利存在大型树栖适应的猴子表明，阿法南方古猿有机会进入一系列多样化的栖息地，包括林地和森林。这支持了这样一种可能性，即阿法南方古猿可能具有多种姿势能力，能够利用树栖环境获取食物并躲避捕食者。
