Serio Carmela, Brown Richard P, Clauss Marcus, Meloro Carlo
Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK.
Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Anat Rec (Hoboken). 2025 Mar;308(3):946-974. doi: 10.1002/ar.25553. Epub 2024 Aug 9.
Long bone ecomorphology has proven effective for paleohabitat reconstructions across a wide range of mammalian clades. Still, there is no comprehensive framework to allow interpretation of long bone morphological variation within and between different monophyletic groups. Here, we investigated the use of humerus morphometry to classify living members of the orders Carnivora and ungulates based on their preferred habitats. Using geometric morphometrics, we extracted three different kinds of humerus shape data describing interspecific variation with and without accounting for evolutionary allometry and phylogenetic signal. The traditional a priori categorization of species in open, mixed, and closed habitats was employed in combination with selected subsets of shape variables to identify the best-predictive models for habitat adaptation. These were identified based on the statistical performance of phylogenetic and non-phylogenetic discriminant analyses and then applied to predict habitats on a subsample of fossil species. Size-free shape data combined with phylogenetic discriminant analyses showed the highest rate of accuracy in habitat classification for a combined sample of carnivorans and ungulates. Conversely, when the two groups were investigated separately, traditional shape data analyzed with phylogenetic discriminant function analyses provided models with the greatest predictive power. By combining carnivorans and ungulates within the same methodological framework we identified common adaptive features in closed habitat-adapted species that show compressed epiphyses, while open habitat-adapted species have expanded epiphyses. These morphologies evolved to allow significant degree of direction switches during locomotion in closed habitats compared to open habitat-adapted species whose forelimb joints evolved to stabilize articulations for increasing speed.
长骨生态形态学已被证明在广泛的哺乳动物类群的古栖息地重建中是有效的。然而，目前还没有一个全面的框架来解释不同单系类群内部和之间长骨形态的变化。在这里，我们研究了利用肱骨形态测量学，根据食肉目和有蹄类动物的偏好栖息地对它们的现存成员进行分类。使用几何形态测量学，我们提取了三种不同类型的肱骨形状数据，分别描述了在考虑和不考虑进化异速生长及系统发育信号的情况下的种间变异。将物种在开阔、混合和封闭栖息地的传统先验分类与选定的形状变量子集相结合，以确定栖息地适应的最佳预测模型。这些模型是根据系统发育和非系统发育判别分析的统计性能确定的，然后应用于预测化石物种子样本的栖息地。无尺寸形状数据与系统发育判别分析相结合，在食肉动物和有蹄类动物的组合样本的栖息地分类中显示出最高的准确率。相反，当分别研究这两个类群时，用系统发育判别函数分析的传统形状数据提供了预测能力最强的模型。通过在同一方法框架内结合食肉动物和有蹄类动物，我们确定了封闭栖息地适应物种的共同适应特征，这些物种的骨骺压缩，而开阔栖息地适应物种的骨骺扩张。与开阔栖息地适应物种相比，这些形态的进化使得在封闭栖息地运动时能够进行显著程度的方向转换，开阔栖息地适应物种的前肢关节进化以稳定关节以提高速度。
