Tapirs have historically been considered as ecologically analogous to several groups of extinct perissodactyls based on dental and locomotor morphology. Here, we investigate comparative functional morphology between living tapirs and endemic Eocene European perissodactyls to ascertain whether tapirs represent viable analogues for locomotion in palaeotheres and lophiodontids. Forelimb bones from 20 species of Eocene European perissodactyls were laser scanned and compared to a forelimb dataset of extant Tapirus . Bone shape was quantified using 3D geometric morphometrics; coordinates were Procrustes aligned and compared using Principal Component Analysis and neighbor-joining trees. Functional traits included lever-arm ratios (LARs; proxy for joint angular velocity), long-bone proportions (speed proxy), and estimated body mass. Results suggest that Paralophiodon and Palaeotherium magnum resemble Neotropical tapirs in humeral morphology and LARs. Palaeotheres demonstrate extensive forelimb shape disparity. Despite previous assessments, metacarpal shape analyzes do not support a strong morphological similarity between palaeotheres and tapirs, with Tapirus pinchaque representing the closest analogue for Eocene European equoid manus morphology. Our analyses suggest lophiodontids were not capable of moving as swiftly as tapirs due to greater loading over the manus. We conclude that the variation within modern tapir forelimb morphology confounds the assignment of one living analogue within Tapirus for extinct European equoids, whereas tapirs adapted for greater loading over the manus (e.g., T. bairdii, T. indicus ) represent viable locomotor analogues for lophiodontids. This study represents a valuable first step toward locomotor simulation and behavioral inference for both hippomorph and tapiromorph perissodactyls in Eocene faunal communities.

中文翻译：

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现代貘作为地方性始新世欧洲 Perissodactyls 运动的形态功能类似物

历史上，貘被认为在生态学上类似于基于牙齿和运动形态的几组已灭绝的奇蹄类动物。在这里，我们研究了活貘和地方性始新世欧洲奇蹄类动物之间的比较功能形态，以确定貘是否代表古兽类和唇齿类动物运动的可行类似物。对 20 种始新世欧洲奇蹄类动物的前肢骨骼进行了激光扫描，并与现存貘的前肢数据集进行了比较。使用 3D 几何形态计量学量化骨骼形状；坐标是 Procrustes 对齐并使用主成分分析和相邻连接树进行比较。功能特征包括杠杆臂比（LAR；关节角速度的代表）、长骨比例（速度代表）和估计的体重。结果表明Paralophiodon 和Palaeotherium magnum 的肱骨形态和LAR 类似于新热带貘。古兽表现出广泛的前肢形状差异。尽管先前的评估，掌骨形状分析不支持古兽和貘之间的强烈形态相似性，貘代表最接近始新世欧洲马蹄目形态的类似物。我们的分析表明，由于手足上的负荷更大，虎齿龙科动物的移动速度不如貘。我们得出结论，现代貘前肢形态的变化混淆了貘内一种活的类似物用于已灭绝的欧洲马科动物的分配，而适应更大负荷的貘（例如，T. bairdii、T. indicus）代表了貘科动物的可行的运动类似物.