Review study of the skeleton of elasmobranchs: a pathological case of the butterfly ray (Gymnura altavela) cartilage.

Abstract

This study investigates the normal anatomy and histology of the spiny butterfly ray (Gymnura altavela) through X-ray, computed tomography (CT), and histological samples, focusing on a specific traumatic injury in one specimen. CT analysis highlights key structures, including the scapular girdle and synarcual, illustrating their connections and support for the pectoral fins. Histological findings reveal non-mineralized cartilage, the calcified tesserae layer, and the muscle structure, emphasizing the role of Sharpey's fibers. The examination of the traumatic injury uncovers significant disruption at the synarcual-scapulocoracoid joint, likely caused by a fishing tool. Imaging shows fractures and gas in the wound area, while histological analysis shows tesserae separation, granulocyte infiltration, and fibrous tissue replacing muscle, indicating a chronic response with no cartilage regeneration. The study aims to enhance our understanding of the biology, conservation needs, and health issues affecting the spiny butterfly ray, a species threatened by human activities. It emphasizes the significant impact of these activities on the species' well-being and underscores the urgent need for conservation measures. The findings also highlight the importance of ongoing research into the health issues faced by elasmobranchs, promoting awareness and efforts to protect these remarkable creatures for future generations.