Osteology of the Thoracic Limb of Geoffroy's Cat (Leopardus geoffroyi) and Jaguar (Panthera onca)

The thoracic limbs of felines are essential for hunting, climbing, jumping, and swimming.This study examines the osteology of wild American felids, addressing the limited knowledge about their anatomy and locomotor apparatus.The findings are relevant for both medical and surgical interventions.Thoracic limbs from five Geoffroy's cats (Leopardus geoffroyi) and four jaguars (Panthera onca) were analyzed using dissection, radiography, computed tomography, and osteological maceration.The studied felids lacked a tubercle on the scapular spine, and the clavicle was small and not connected to the skeleton.The humerus presented a supracondylar foramen for the median nerve and brachial artery.Jaguars showed a more developed medial styloid process, and both species had well-defined radius and ulna bones, with a larger interosseous space in Geoffroy's cats.Both species had seven carpal bones and five metacarpal bones, which were more robust in the jaguar.The presence of a sesamoid bone associated with the abductor longus muscle of the first digit (digit I) suggests enhanced manipulation and grasping ability.The phalanges were short, with surfaces adapted for tendon insertion.The middle phalanx was absent in the first digit, and the distal phalanx was associated with curved claws, possibly related to claw retraction.In conclusion, notable anatomical differences exist between jaguars and Geoffroy's cats, likely reflecting the distinct locomotor and predatorydemands associated with capturing prey of different sizes.