Anapol F, Fleagle J G
Department of Oral Anatomy, College of Dentistry, University of Illinois, Chicago 60612.
Am J Phys Anthropol. 1988 Aug;76(4):417-28. doi: 10.1002/ajpa.1330760402.
Primate scapula and ulna fragments of uncertain taxonomic affinity (MACN-SC 101) have been recovered from the Pinturas deposits at Arroyo Feo, Santa Cruz, Argentina in association with Santacrucian (Early Miocene) land mammals. Least-squares regression of body weight on surface area and on height of the glenoid fossa of the scapula indicates an estimated mean weight of 3.6 kg for this individual. On the basis of qualitative and several metric features, the fossil scapula and ulna most closely resemble living platyrrhine monkeys. In estimated body weight and relative height of the coronoid process, the fossil is similar to arboreal quadrupeds, such as Cebus apella and Chiropotes. However, spinoglenoid, axilloglenoid, and axillospinal angles, length of lever arm, and length and breadth of the sigmoid notch imply behavioral similarity with larger species that also use their forelimbs extensively in climbing, such as Alouatta and Lagothrix. MACN-SC 101 may represent the incipient divergence of a generalized platyrrhine arboreal quadruped toward a more suspensory form.
分类学亲缘关系不确定的灵长类肩胛骨和尺骨碎片（MACN - SC 101）是在阿根廷圣克鲁斯省阿罗约费奥的平图拉斯沉积物中发现的，与桑塔克鲁cian期（中新世早期）的陆生哺乳动物伴生。通过对体重与肩胛骨关节盂表面积和高度进行最小二乘回归分析，估计该个体的平均体重为3.6千克。基于定性和多个测量特征，化石肩胛骨和尺骨与现存的阔鼻猴最为相似。在估计体重和冠状突相对高度方面，该化石类似于树栖四足动物，如僧帽猴和绒毛蛛猴。然而，肩胛下肌、腋盂和腋棘角度、杠杆臂长度以及乙状切迹的长度和宽度表明，其行为与在攀爬中也广泛使用前肢的较大物种（如蛛猴和绒毛猴）相似。MACN - SC 101可能代表了一种广义的阔鼻猴树栖四足动物向更具悬垂性形态的初始分化。
