Rodents of the family Octodontidae, endemic to South America, represent a group with low taxonomic richness group (six genera and 14 species) but have great ecomorphological diversity with epigean, semi-fossorial, fossorial, and subterranean forms. We analyzed morphometric variation in humerus and ulna, the possible relationship with substrate preference use, and the presence of a phylogenetic signal in the forelimbs traits (five biomechanical indices). Our results show that, in octodontids, the forelimb variation was not primarily associated with their phylogeny and some attributes are highly explanatory in terms of function, with a clear differentiation between the substrate use gradient extremes (i.e. epigean and subterranean forms). The two forelimb traits, the development of humeral epicondyles and the olecranon process of the ulna, indicative of adaptive trends found in Octodontidae are consistent with most of those described for other mammals and corroborate the relevance of forelimb characters to differentiate modes of locomotion or substrate preferences.

中文翻译：

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Octodontidae (Rodentia: Mammalia) 的前肢：底物使用、形态学和系统发育信号

Octodontidae 的啮齿动物是南美洲特有的，代表了一个分类丰富度较低的群体（6 属 14 种），但具有丰富的生态形态多样性，具有表生、半化石、化石和地下形态。我们分析了肱骨和尺骨的形态学变异、与底物偏好使用的可能关系以及前肢特征（五个生物力学指标）中系统发育信号的存在。我们的结果表明，在八齿类动物中，前肢变异与其系统发育无关，并且某些属性在功能方面具有高度解释性，底物使用梯度极端（即表层和地下形式）之间有明显区别。两个前肢特征，肱骨上髁的发育和尺骨的鹰嘴突，