Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA; New York Consortium in Evolutionary Primatology (NYCEP), USA.
Center for Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA.
J Hum Evol. 2019 Mar;128:59-75. doi: 10.1016/j.jhevol.2018.12.010. Epub 2019 Feb 10.
Kamoyapithecus hamiltoni is a potential early hominoid species described from fragmentary dentognathic specimens from the Oligocene site of Losodok (Turkana Basin, northwestern Kenya). Other catarrhine dental materials have been recovered at Losodok, but were not initially included in the Kamoyapithecus hypodigm. Here we present descriptions of the unpublished canine and incisor specimens from Losodok, and revisit the published specimens in light of recent changes in understanding of hominoid anterior dental evolution. The new fossils include a canine (KNM-LS 18354) that is morphologically compatible with being a female of Kamoyapithecus (KNM-LS 8). Randomization analyses of both Gorilla gorilla and middle Miocene Griphopithecus alpani demonstrate that the size difference between KNM-LS 8 and KNM-LS 18354 is also compatible with their being male and female canines of the same species. Significantly, a canine tip (KNM-LS 18352) attributed to Kamoyapithecus documents the distinctive burin tip morphology now recognized as characterizing Proconsul sensu stricto, which may indicate a close relationship between Kamoyapithecus and Proconsul. We also re-examined the enigmatic KNM-LS 1, a smaller lower canine assumed to derive from Losodok but for which historical provenience data are completely lacking. Elemental data derived from portable X-ray fluorescence spectroscopy show that KNM-LS 1 is almost certainly from Losodok rather than from nearby Miocene sites (i.e., Moruorot, Esha, Kalodirr). KNM-LS 1 displays a nyanzapithecine-like morphology and is shown by randomization analyses to be too small to be associated with the Kamoyapithecus canines. This demonstrates that there is a second hominoid taxon present at Losodok that records one of the earliest occurrences of the Nyanzapithecinae.
坎亚皮特猴是一种可能的早期人科物种，其描述基于来自肯尼亚西北部图尔卡纳盆地洛索多克（Losodok）渐新世遗址的零碎牙颌标本。洛索多克还发现了其他的大型猫科动物牙齿材料，但最初并未包含在坎亚皮特猴的模式标本中。在这里，我们描述了洛索多克未发表的犬齿和门齿标本，并根据近期对人科前牙演化的理解变化重新审视了已发表的标本。这些新化石包括一个犬齿（KNM-LS 18354），其形态与坎亚皮特猴的雌性（KNM-LS 8）相符。对大猩猩和中中新世的格里芬古猿的随机化分析表明，KNM-LS 8 和 KNM-LS 18354 之间的大小差异也与其同为同一物种的雄性和雌性犬齿相符。重要的是，一个犬齿尖端（KNM-LS 18352）归因于坎亚皮特猴，它记录了现在被认为是特征明确的原康修尔猿的独特凿形尖端形态，这可能表明坎亚皮特猴和原康修尔猿之间存在密切关系。我们还重新检查了神秘的 KNM-LS 1，这是一个较小的下犬齿，假定来自洛索多克，但历史来源数据完全缺失。便携式 X 射线荧光光谱法得出的元素数据表明，KNM-LS 1 几乎可以肯定来自洛索多克，而不是来自附近的中新世遗址（即莫罗罗特、埃沙、卡洛迪尔）。KNM-LS 1 显示出一种 Nyanzapithecine 样的形态，并且通过随机化分析表明其太小，不可能与坎亚皮特猴的犬齿相关联。这表明，在洛索多克存在第二个人科分类群，记录了 Nyanzapithecinae 的最早出现之一。
