Department of Anthropology, Yale University, New Haven, CT 06520-8277, USA.
Am J Phys Anthropol. 2010 Mar;141(3):418-29. doi: 10.1002/ajpa.21160.
Papionin monkeys are widespread, relatively common members of Plio-Pleistocene faunal assemblages across Africa. For these reasons, papionin taxa have been used as biochronological indicators by which to infer the ages of the South African karst cave deposits. A recent morphometric study of South African fossil papionin muzzle shape concluded that its variation attests to a substantial and greater time depth for these sites than is generally estimated. This inference is significant, because accurate dating of the South African cave sites is critical to our knowledge of hominin evolution and mammalian biogeographic history. We here report the results of a comparative analysis of extant papionin monkeys by which variability of the South African fossil papionins may be assessed. The muzzles of 106 specimens representing six extant papionin genera were digitized and interlandmark distances were calculated. Results demonstrate that the overall amount of morphological variation present within the fossil assemblage fits comfortably within the range exhibited by the extant sample. We also performed a statistical experiment to assess the limitations imposed by small sample sizes, such as typically encountered in the fossil record. Results suggest that 15 specimens are sufficient to accurately represent the population mean for a given phenotype, but small sample sizes are insufficient to permit the accurate estimation of the population standard deviation, variance, and range. The suggestion that the muzzle morphology of fossil papionins attests to a considerable and previously unrecognized temporal depth of the South African karst cave sites is unwarranted.
狒狒科猴广泛分布于整个非洲的上新世至更新世动物群，是相对常见的成员。由于这些原因，狒狒科分类单元被用作推断南非喀斯特洞穴沉积物年代的生物年代指标。最近对南非化石狒狒科口鼻形状的形态计量学研究得出结论，其变异证明了这些地点的时间深度比通常估计的要大得多。这一推断意义重大，因为准确确定南非洞穴遗址的年代对于我们了解人类进化和哺乳动物生物地理历史至关重要。我们在这里报告了对现生狒狒科猴子进行比较分析的结果，以便评估南非化石狒狒科的可变性。对代表六个现生狒狒科属的 106 个标本的口鼻进行了数字化处理，并计算了地标间的距离。结果表明，化石组合中存在的形态变异总量与现生样本所表现出的范围非常吻合。我们还进行了一项统计实验，以评估小样本量（例如在化石记录中通常遇到的情况）所带来的限制。结果表明，15 个标本足以准确代表给定表型的群体平均值，但小样本量不足以准确估计群体标准差、方差和范围。化石狒狒科口鼻形状证明了南非喀斯特洞穴遗址具有相当大的、以前未被认识到的时间深度的说法是没有根据的。
