Sargis Eric J
Department of Anthropology, City University of New York, New York, New York 10016, USA.
J Morphol. 2002 Nov;254(2):149-85. doi: 10.1002/jmor.10025.
In this study, the hindlimb of 12 species of tupaiids was analyzed functionally and compared to that of primates, dermopterans, and chiropterans. Many aspects of the tupaiid hindlimb vary in relation to differential substrate use. These differences include width of the ilium, shape of the acetabulum, size of the anterior inferior iliac spine, size of the greater and third trochanters, depth of the femoral condyles, shape of the patellar groove, and size of the tibial tuberosity. The hindlimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, whereas that of tupaiines is better adapted for rapid terrestrial (or scansorial) locomotion. The hindlimb of Ptilocercus seems to be habitually flexed and has more joint mobility, a condition necessary for movement on uneven, discontinuous arboreal supports. The tarsus of Ptilocercus facilitates inversion of the foot and its grasping hallux is capable of a great range of abduction. Tupaiines, on the other hand, are characterized by more extended hindlimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. The hindlimb of tupaiines is adapted for powerful flexion and extension. Even the most arboreal tupaiines remain similar to terrestrial tupaiines in their hindlimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). Many attributes of the tupaiid hindlimb, especially those of the foot, reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the hindlimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans, and it is proposed that the hindlimb features of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia.
在本研究中，对12种树鼩科物种的后肢进行了功能分析，并与灵长类、皮翼目和翼手目的后肢进行了比较。树鼩科后肢的许多方面因不同的底物利用情况而有所不同。这些差异包括髂骨宽度、髋臼形状、髂前下棘大小、大转子和第三转子大小、股骨髁深度、髌槽形状以及胫骨粗隆大小。唯一的笔尾树鼩属物种——树栖的笔尾树鼩（Ptilocercus lowii）的后肢更适合树栖运动，而树鼩属的后肢则更适合快速的陆地（或树栖兼陆栖）运动。笔尾树鼩的后肢似乎习惯性地弯曲，且关节活动度更大，这是在不平坦、不连续的树栖支撑物上移动所必需的条件。笔尾树鼩的跗骨有利于足部内翻，其可抓握的拇趾能够进行大幅度外展。另一方面，树鼩属的特征是后肢更伸展，关节活动度较小。这些受限的关节将运动更多地限制在矢状旁平面内，这提高了在像地面这样更平坦、连续的表面上运动的效率。树鼩属的后肢适合有力的屈伸。即使是最树栖的树鼩属物种，其后肢形态也与陆栖树鼩属物种相似，这可能反映了树鼩亚科（但不是树鼩科）的陆地祖先。树鼩科后肢的许多特征，尤其是足部的特征，反映了树鼩科的树栖祖先，并且有人提出，树鼩科的祖先像笔尾树鼩一样是树栖的。此外，与树鼩属的后肢特征状态相比，笔尾树鼩的后肢特征状态与其他真灵长大目动物的更相似，并且有人提出，笔尾树鼩的后肢特征是树鼩科的原始特征。因此，在任何包括树鼩目的系统发育分析中都应考虑笔尾树鼩。
