Department of Anthropology, Texas A&M University, Anthropology 225, TAMU 4352, College Station, TX, 77843, USA.
J Hum Evol. 2021 Jul;156:103012. doi: 10.1016/j.jhevol.2021.103012. Epub 2021 May 15.
The postcranium of a large-bodied colobine monkey attributed to Paracolobus mutiwa from the site of Lomekwi, West Turkana, Kenya, is described. The partial skeleton (KNM-WT 16827) was recovered from locality LO 1, dated to 2.58-2.53 Ma, and preserves postcranial elements including fragments of scapula, humerus, proximal ulna, proximal radius, os coxae, proximal femur, astragalus, and calcaneus. KNM-WT 16827 was identified as P. mutiwa based on cranial similarities to the holotype female maxilla (KNM-ER 3843) and the holotype of Paracolobus chemeroni (KNM-BC 3), but is currently the only specimen of this taxon with associated cranial and postcranial elements. The skeleton is morphologically distinct from other large cercopithecid specimens from the Turkana Basin, including several assigned to Cercopithecoides williamsi, Cercopithecoides kimeui, Rhinocolobus turkanaensis, and Theropithecus oswaldi and differs from KNM-BC 3 in the larger cranium and shorter and more robust long bones. KNM-WT 16827 has forelimb and hindlimb features exhibiting a mixture of traits more associated with terrestrial locomotor behavior, including robust humeral deltoid tuberosity, retroflexed humeral medial epicondyle, deep ulnar trochlear notch, relatively short lower iliac height, prominent femoral greater trochanter, asymmetrical astragalar trochlea, and weak digit flexor grooves on the calcaneus. KNM-WT 16827 is also proportionally distinct from KNM-BC 3 and other Turkana Basin specimens attributed to large-bodied taxa such as C. williamsi, C. kimeui, R. turkanaensis, and T. oswaldi in having relatively shorter limbs and smaller tarsals. The traits shared with P. chemeroni and other extinct taxa are either typical for colobines, or likely due to P. mutiwa and P. chemeroni sharing adaptations for terrestrial locomotion relative to extant colobinans. Although a full cranial assessment is needed, based on its postcranial morphology KNM-WT 16827 is distinct from KNM-BC 3, C. williamsi, R. turkanaensis, Theropithecus, and extant colobines, warranting further analyses to better assess the taxonomic assignment of the specimen.
描述了一件来自肯尼亚图尔卡纳湖以西洛梅奎地点的大型疣猴后肢骨骼，归入 Mutia 副山魈属（Paracolobus mutiwa）。该部分骨骼（KNM-WT 16827）出土于 LO 1 地点，年代为 2.58-2.53 百万年前，保存有后肢骨骼的一些部分，包括肩胛骨、肱骨、近端尺骨、近端桡骨、髋骨、股骨近端、距骨和跟骨。KNM-WT 16827 基于与副山魈属的模式雌性上颌骨（KNM-ER 3843）和 Chemeroni 副山魈（KNM-BC 3）的模式种相似，被鉴定为 P. mutiwa，但目前是该分类群中唯一具有相关颅骨和后肢骨骼的标本。该骨骼在形态上与图尔卡纳盆地的其他大型灵长类标本不同，包括一些被归入威廉斯山魈（Cercopithecoides williamsi）、基梅尤山魈（Cercopithecoides kimeui）、Turkana 山魈（Rhinocolobus turkanaensis）和狒狒（Theropithecus oswaldi）的标本，与 KNM-BC 3 相比，它具有更大的颅骨和更短而粗壮的长骨。KNM-WT 16827 的前肢和后肢特征表现出与陆地运动行为更相关的特征的混合，包括强壮的肱骨三角肌粗隆、后屈的肱骨内侧上髁、深的尺骨滑车切迹、相对较短的髂骨高度、突出的股骨大转子、不对称的距骨滑车、以及跟骨上弱的趾屈肌沟。KNM-WT 16827 与 KNM-BC 3 和其他图尔卡纳盆地的标本在比例上也不同，这些标本归因于大型分类群，如威廉斯山魈、基梅尤山魈、Turkana 山魈和狒狒，因为它们的四肢相对较短，跗骨较小。与 Chemeroni 副山魈和其他已灭绝的分类群共享的特征要么是疣猴的典型特征，要么可能是由于 Mutiwa 副山魈和 Chemeroni 副山魈相对于现存的疣猴类具有适应陆地运动的特征。尽管需要进行全面的颅骨评估，但根据其后肢形态，KNM-WT 16827 与 KNM-BC 3、威廉斯山魈、Turkana 山魈、狒狒和现存的疣猴类不同，需要进一步的分析来更好地评估标本的分类归属。
