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.

A quantitative method for inferring locomotory shifts in amniotes during ontogeny, its application to dinosaurs and its bearing on the evolution of posture

“…Although observed as being habitual bipeds (Steyn et al . ) all four ground pangolin specimens ( Smutsia temminckii ) are predicted by the DFA to be quadrupedal or equivocal (0.167 ≤ pp bipedal ≤ 0.561) (Fig. ).…”

“…Some bipedal animals have robust humeri, including the ground pangolin Smutsia temminckii , which is a burrower (Steyn et al . ), and large kangaroos ( Macropus giganteus and Macropus rufus ). Smutsia temminickii was classified as a biped in our dataset, and indeed makes relatively little use of the forelimb during locomotion.…”

Anátomo-radiografia dos ossos longos do membro torácico do Tamandua tetradactyla

“…Tendo em vista a importância dos braços do T. tetradactyla, quanto a sua função de escavar para fins alimentares, bem como para defesa (Gambaryan et al 2009), o úmero destes animais apresentou-se robusto e relativamente curto, subsidiando estas habilidades, assim como avaliado no Smutsia temminckii (Steyn et al 2018), espécie mimercofaga, com hábitos muito semelhantes aos do T. tetradactyla.…”

“…Os acidentes anatômicos do úmero do T. tetradactyla, situados na extremidade proximal revelaram igual conformação a descrita em E. sexcinctus (Alberto et al 2010), M. tridactyla (Lima et al 2013) e S. temminckii (Steyn et al 2018), animais que curiosamente são pertencentes a Superordem Xenarthra, no caso dos dois primeiros, e o terceiro, apesar de pertencer a outra Ordem (Pholidota), como supramencionado, utilizam o membro torácico para os mesmos fins, o que poderia justificar tais compatibilidades morfológicas.…”

“…Diferentemente do descrito em M. tridactyla (Lima et al 2013), em T. tetradactyla a tuberosidade para o músculo redondo maior não foi identificada, descrito por exemplo no cão (Plana et al 2018), em T. terrestris (Pereira et al 2015) e no S. temminckii (Steyn et al 2018), no entanto, tendo em vista que tal acidente anatômico é apenas um dos responsáveis pela inserção de músculos que retraem o membro torácico, acredita-se que sua ausência não implica diretamente na realização deste movimento.…”