Hou Lily, Bertrand Ornella C, Mudannayake Hiruni N, Rolian Campbell, Cote Susanne
Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada.
Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA), Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Cerdanyola del Vallès, Barcelona, Spain.
J Anat. 2025 Nov;247(5):953-969. doi: 10.1111/joa.14263. Epub 2025 May 6.
Anatomical structures vary among mammals with different locomotor behaviours, including sensory structures such as the semicircular canals (SCCs) in the inner ear. Recent SCC research has examined various mammalian groups, but there has been a lack of research on rodents, the most speciose and diverse mammalian order. In this study, an extant sample of 98 rodent SCCs from 56 species across seven different locomotor behaviour categories (arboreal, fossorial, gliding, ricochetal, semiaquatic, semifossorial, terrestrial) was used to understand the correlations between SCC morphology and locomotion in rodents. Morphological correlates considered include the radius of curvature (R), overall 3-dimensional shape, and angles between pairs of canals (orthogonality). Our results show that agile arboreal taxa have larger R for their body size, and fossorial taxa have smaller R for their body size. Shape among specialized locomotor behaviours (arboreal, gliding vs. fossorial) can be differentiated, while other "generalist" categories overlap in morphospace. Specialized locomotor categories can be predicted with greater precision and sensitivity, while other generalist categories tend to be miscategorized as terrestrial. Angles between canals are not consistent across locomotor categories, and more agile groups do not have more orthogonal angles, contrary to our predictions. SCC R and overall shape are robust indicators of specialized locomotor behaviours and can be informative in reconstructing the behaviour of fossil rodents.
不同运动行为的哺乳动物其解剖结构存在差异，包括内耳中的半规管（SCCs）等感觉结构。最近对半规管的研究考察了各种哺乳动物群体，但对啮齿动物这一最为多样且种类繁多的哺乳动物目却缺乏研究。在本研究中，我们使用了来自七个不同运动行为类别（树栖、穴居、滑翔、跳跃、半水生、半穴居、陆生）的56个物种的98个现存啮齿动物半规管样本，以了解半规管形态与啮齿动物运动之间的相关性。所考虑的形态学关联因素包括曲率半径（R）、整体三维形状以及各对半规管之间的夹角（正交性）。我们的结果表明，敏捷的树栖类群相对于其体型具有更大的曲率半径，而穴居类群相对于其体型则具有较小的曲率半径。特殊运动行为（树栖、滑翔与穴居）之间的形状可以区分，而其他“一般化”类别在形态空间中存在重叠。特殊运动类别能够以更高的精度和敏感度进行预测，而其他一般化类别往往会被误分类为陆生。各运动类别中半规管之间的夹角并不一致，与我们的预测相反，更敏捷的类群并不具有更多的正交夹角。半规管的曲率半径和整体形状是特殊运动行为的有力指标，对于重建化石啮齿动物的行为具有参考价值。
