The mammalian family Bovidae has been widely studied in ecomorphological research, with important applications to paleoecological and paleohabitat reconstructions. Most studies of bovid craniomandibular features in relation to diet have used linear measurements. In this study, we conduct landmark-based geometric-morphometric analyses to evaluate whether different dietary groups can be distinguished by mandibular morphology. Our analysis includes data for 100 species of extant bovids, covering all bovid tribes and 2 dietary classifications. For the first classification with 3 feeding categories, we found that browsers (including frugivores), mixed feeders, and grazers are moderately well separated using mandibular shape. A finer dietary classification (frugivore, browser, browser–grazer intermediate, generalist, variable grazer, and obligate grazer) proved to be more useful for differentiating dietary extremes (frugivores and obligate grazers) but performed equally or less well for other groups. Notably, frugivorous bovids, which belong in tribe Cephalophini, have a distinct mandibular shape that is readily distinguished from all other dietary groups, yielding a 100% correct classification rate from jackknife cross-validation. The main differences in mandibular shape found among dietary groups are related to the functional needs of species during forage prehension and mastication. Compared with browsers, both frugivores and grazers have mandibles that are adapted for higher biomechanical demand of chewing. Additionally, frugivore mandibles are adapted for selective cropping. Our results call for more work on the feeding ecology and functional morphology of frugivores and offer an approach for reconstructing the diet of extinct bovids.

中文翻译：

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用于牛科（哺乳动物：偶蹄目）膳食分化的下颌骨几何形态学

哺乳动物科牛科已在生态形态学研究中得到广泛研究，在古生态和古生境重建中具有重要应用。大多数关于与饮食相关的牛科颅颌骨特征的研究都使用了线性测量。在这项研究中，我们进行了基于地标的几何形态测量分析，以评估是否可以通过下颌形态区分不同的饮食组。我们的分析包括 100 种现存牛科动物的数据，涵盖所有牛科动物部落和 2 个饮食分类。对于具有 3 个喂养类别的第一个分类，我们发现浏览器（包括食果动物）、混合饲养者和食草动物使用下颌形状适度分离。更精细的饮食分类（食果动物、浏览器、浏览器-食草动物中间型、通才型、可变食草动物、和专性食草动物）被证明对区分极端饮食（食果动物和专性食草动物）更有用，但对其他群体的表现相同或较差。值得注意的是，属于 Cephalophini 部落的食果牛科动物具有明显的下颌形状，很容易与所有其他饮食组区分开来，通过折刀交叉验证产生 100% 的正确分类率。膳食组之间发现的下颌骨形状的主要差异与物种在草料捕捉和咀嚼过程中的功能需求有关。与浏览器相比，食果动物和食草动物都具有适应咀嚼的更高生物力学需求的下颌骨。此外，食果动物的下颌骨适合选择性种植。