Scanning electron microscopic observation of lingual papillae in a Bengal tiger (Panthera tigris tigris)

Abstract

The morphology of the lingual papillae in a female Bengal tiger (Panthera tigris tigris) was examined by scanning electron microscopy (SEM). The tongue was 22.3 cm in length and 7.1 cm in width. Numerous filiform papillae were distributed over the entire dorsal surface of the tongue. SEM examination of the tongue revealed two types of mechanical papillae, i.e. filiform and conical papilla, and two types of gustatory papillae, i.e. fungiform and vallate papilla, on the dorsal surface of the tongue. Each filiform papilla consisted of one primary papilla and several secondary papillae. The filiform papillae on the anterior part of the tongue were divided into one primary and 6~14 secondary papillae. Unlike other mammalians, however, secondary papillae in the mid-part of the tongue showed pineal-like papillae. In the posterior part of the tongue, secondary papillae were rare or absent. Fungiform papillae were surrounded by filiform papillae and densely distributed on the lingual surface. There were two vallate papillae on the borderline between the lingual body and root of the tongue. A vallate papilla contained two secondary papillae inside the grooves. Conical papillae were located in the area of the vallate papillae and covered the posterior part of the tongue root. No foliate papillae were seen on both margins of the posterior part of the tongue. Our results indicate that the structure on the lingual papillae of the Bengal tiger is somewhat different from that of other mammals.