Abstract The interaction between organisms and their environment is central in functional morphology. Differences in habitat usage may imply divergent morphology of locomotor systems; thus, detecting which morphological traits are conservative across lineages and which ones vary under environmental pressure is important in evolutionary studies. We studied internal and external morphology in 28 species of Neotropical anurans. Our aim was to determine if internal morphology (muscle and tendons) shows lower phylogenetic signal than external morphology. In addition, we wanted to know if morphology varies in relation to the habitat use and if there are different functional groups. We found differences in the degree of phylogenetic signal on the groups of traits. Interestingly, postaxial regions of the forelimb are evolutionarily more labile than the preaxial regions. Phylomorphospace plots show that arboreal (jumpers and graspers) and swimmer frogs cluster based on length of fingers and the lack of sesamoid, also reflected by the use of habitat. These functional clusters are also related to phylogeny. Sesamoid and flexor plate dimensions together with digit tendons showed to be important to discriminate functional groups as well as use of habitat classification. Our results allow us to identify a “grasping syndrome” in the hand of these frogs, where palmar sesamoid and flexor plate are absent and a third metacarpal with a bony knob are typical. Thus, a lighter skeleton, long fingers and a prensile hand may be key for arboreality.

中文翻译：

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阿努拉前肢肌肉腱结构及其与运动模式和栖息地利用的关系

摘要 生物体与其环境之间的相互作用是功能形态学的核心。栖息地使用的差异可能意味着运动系统的不同形态；因此，检测哪些形态特征在不同谱系中是保守的，哪些形态特征在环境压力下发生变化，在进化研究中很重要。我们研究了 28 种新热带无尾动物的内部和外部形态。我们的目的是确定内部形态（肌肉和肌腱）是否显示出比外部形态更低的系统发育信号。此外，我们想知道形态是否随栖息地使用而变化，以及是否存在不同的功能群。我们发现性状组的系统发育信号程度存在差异。有趣的是，前肢的轴后区域在进化上比轴前区域更不稳定。叶形态空间图显示，树栖蛙（跳跃蛙和抓握蛙）和游泳蛙基于手指的长度和籽骨的缺乏而聚集，这也反映在栖息地的利用上。这些功能簇也与系统发育有关。籽骨和屈肌板的尺寸以及指腱对于区分功能群以及栖息地分类的使用非常重要。我们的结果使我们能够识别出这些青蛙手上的“抓握综合症”，其中手掌籽骨和屈肌板缺失，并且具有骨节的第三掌骨是典型的。因此，较轻的骨骼、较长的手指和灵活的手可能是树栖的关键。