Appendicular Skeleton of the Three-Toed Sloth (<em>Bradypus variegatus</em>) and Its Insights for Arboreal Adaptation in the Amazon Region

The brown-throated three-toed sloth (Bradypus variegatus) exhibits unique suspensory locomotion that reflects specialized morphological adaptations to an arboreal lifestyle in the Amazon. This study aimed to describe the appendicular skeleton of B. variegatus using computed tomography (CT), providing detailed anatomical insights related to arboreal movement. CT scans were conducted on nine juvenile sloth cadavers, enabling three-dimensional visualization of thoracic and pelvic limb structures, including bones, joint configurations, and vestigial elements. Key findings include greater development of thoracic limbs compared to pelvic limbs, the absence of a clavicle suggesting vestigiality, fusion of carpal bones, and elongated claws—features that enhance limb strength, stability, and muscle attachment for suspensory behavior. Additionally, morphological traits such as a rounded acetabulum and laterally wide pubis support arboreal locomotion. The absence of a patella and variable ossification patterns also highlight evolutionary divergence and functional adaptations. These results contribute to our understanding of xenarthran morphology and offer valuable data for comparative anatomy, evolutionary biology, and conservation. Further studies are recommended to explore adult specimens and expand morphometric analyses.