The Tongue and Associated Structures in Two Species of African Pangolins, Manis gigantea and Manis tricuspis

Abstract

The tongue, together with its associated structures, was studied in two species of African pangolins, Manis gigantea and M. tricuspis. Observa- tions were made on living animals, and anatomical studies were made on seven adults. The tongue, 70 centimeters long in Manis gigantea and 30 centimeters long in M. tricuspis, is of similar morphology in the two species. It lies ventral to the larynx and trachea and occupies the thorax and abdomen just internal to the body waIl. A description is given of the mandible, hyoid, and sternum; the attachments of transverse and longitudinal tongue protrudor and retractor muscles; the histology of the tongue epithelium and lytta; the intrinsic muscle arrangements and the salivary glands. The structural features are related to the specialized pangolin mode of food gathering, and compared with similar arrangements present in other mammals which feed on a diet requiring little or no mastication. African pangolins exhibit many interesting anatomical specializations. The forelimbs are pronograde and well adapted for tearing apart termite nests; the dorsal and lateral body hair is modified to form scale-like plaques; the tail is extremely muscular, contains a large complex retia mirabilia, and in the arboreal species possesses a terminal caudal sensory pad containing many Pacinian corpuscles. Such morphological adaptations and those of the tongue and jaws are specializations to a particular diet and mode of life, namely, anteating. Accounts of the tongue and associated structures in the Pholidota are con- fined to brief, and not wholly consistent reports. Cuvier (1845), Weber (1894), and Beddard (1909) described various aspects of pangolin anatomy, but only mentioned the tongue in passing. The anatomy of the taste organs of the tongue has been described in detail (Bronn, 1874; Tuckerman, 1890; Sonntag, 1923; Kubota et al., 1962). Our study is the first to consider in detail the structure, myology, nerve supply, and function of the tongue in the Pholidota.