Morphology of the digestive tract of Temminck’s pangolin (Smutsia temminckii)

Abstract

The myrmecophagous Temminck’s pangolin (Smutsia temminckii) is the only pangolin species present in southern Africa. The mandibular salivary glands are extremely well-developed. The elongated tongue is protrusible and forms a ventral U-shaped flexure when housed in a sheath at the base of the neck. The base of the tongue displays muscular attachments to the dorsal surface of the elongated, spatula-shaped xiphisternum which extends into the abdominal cavity. The stomach mucosa is mostly non-glandular, with a well-circumscribed glandular area in the corpus region of the stomach. The pylorus is very muscular. The intestines is more typical of carnivores and the caecum is absent. The liver is well-lobated. The pangolin tongue is reported to extend into the abdominal cavity. However, this study demonstrated that the tongue remains in the oropharyngeal cavity and that the extrinsic tongue muscles are greatly modified to extend into the abdomen. The large salivary glands, together with the specialised sheath of the tongue, would allow for the trapped ingesta to slide off the tongue, be collected into a bolus and swallowed. The circumscribed glandular area in the stomach is a normal finding and should not be confused with ulceration. The discoglandular stomach allows for extended chitin digestion proximally and mechanical digestion distally. Highly lobated livers allows for rearrangement of lobes during maximal spinal flexion which is typical for pangolins that roll into a ball when threatened. The modified tongue muscles and xiphisternum are important considerations in abdominal surgery and for interpreting diagnostic imaging.