Bone histological evidence for posture-related load transmission in the talpid pectoral girdle

作者：Nakai D · 发表于：Journal of anatomy · 年份：2026 · DOI：10.1111/joa.70222 · 被引用次数：82 · 研究领域：Talpidae、collagen fibre orientation、forelimb posture、functional histology、pectoral girdle

The pectoral girdle of terrestrial tetrapods functions as a critical interface for transmitting loads between the trunk and forelimbs. While mammals with a parasagittal forelimb posture mainly rely on the scapula as the principal element for load bearing, talpids (Talpidae) exhibit a markedly specialised pectoral girdle related to a hyper-abducted forelimb posture. In talpids, the humero-clavicular articulation plays an important functional role, suggesting that load-transmission mechanisms within the pectoral girdle may differ from those of typical terrestrial mammals. However, because the pectoral girdle of talpids is highly developed as a fossorial adaptation, it is difficult to infer the mechanical environments experienced by each skeletal element from external morphology alone, and the mechanical roles of the pectoral girdle elements are poorly understood. To examine whether posture-related reorganisation of load-transmission pathways is reflected in bone microstructure, collagen fibre orientation weighted mean greyscale level (CFO-WMGL) and cortical bone robusticity (relative robusticity indicator: RRI) in the clavicle and scapula were evaluated in fossorial talpids (Mogera imaizumii, Mogera wogura and Urotrichus talpoides) and compared with those of the parasagittal outgroup Suncus murinus. Talpids exhibited high RRI values in both the clavicle and scapula, indicating overall mechanical reinforcement of the pectoral girdle. In contrast, CFO-WMGL showed element-specific...