Enhanced Forelimb Mobility in Insular Meles populations: Insights from Myological and Osteological Comparisons

Abstract Island colonization can drive anatomical adaptations in mammals, yet few studies have examined how such changes occur in limb musculature and osteology. Here, we investigate the forelimb anatomy of Meles badgers to understand functional adaptations associated with insular environments. We conducted detailed myological dissections of the Japanese badger (Meles anakuma) and its continental relative (Meles leucurus), and compared osteological features with another continental-insular pair: Meles meles from mainland Europe and Meles canescens from Crete. Our results reveal several previously undescribed features, including the presence of m. tensor fasciae antebrachii in Meles, and a distal shift in the main belly of m. coracobrachialis in M. anakuma, both with considerable phylogenetic ramifications. While body size did not differ significantly between M. anakuma and M. leucurus, insular populations of both M. anakuma and M. canescens exhibit shared osteological traits, such as reduced projection of the humeral trochlea and enlargement of the cranial aspect of the ulnar head, which likely enhance forelimb mobility rather than maximize digging force. These results may indicate that insular Meles have evolved increased joint flexibility, potentially as an adaptation for locomoter versatility in more structurally complex or variable island habitats. Our findings establish Meles as a valuable model for studying evolutionary responses to island environments in subfossorial mesocarnivores.