Osteology and Radiological Anatomy of the Thoracic Limbs of Temminck's Ground Pangolin (Smutsia temminckii).

Abstract

Temminck's ground pangolin is the only pangolin present in South Africa. It is a myrmecophagous mammal with a bipedal gait. The thoracic limbs are used to break open ant nests, dig for food, and expand previously occupied burrows. This study describes the osteology and radiological anatomy of the thoracic limbs of this threatened species. Thoracic limbs from four Temminck's ground pangolins, which succumbed from electrocution or natural causes, were digitally radiographed in situ. The individual bones were then cleaned, described and digitally radiographed. The skeleton of the thoracic limbs revealed a similar number and arrangement of bones compared to that of domestic carnivores. The bones were robust and displayed numerous open epiphyseal lines. The latter provide an estimate of sexual maturity and should not be confused with fractures in injured ground pangolins. The scapula was broad and triangular-shaped. The humerus displayed a massive medial epicondyle. The radius and ulna were similarly sized, and displayed a broad radial trochlea and large olecranon tuber, respectively. The manus was composed of seven carpal bones, five short metacarpal bones and five digits of which the three central digits were the best developed. The unguicular process of the distal phalanx was bifid and elongated. The osteological characteristics indicate that the thoracic limbs of Temminck's ground pangolin are specifically adapted for protraction and retraction, strong elbow extension, flexion of the carpus and digits as well as pronation and supination of the antebrachium, as opposed to weight-bearing. These functions are likewise documented for other scratch-digging species. Anat Rec, 301:624-635, 2018. © 2017 Wiley Periodicals, Inc.