Morphological study of the Lingual papillae of Jentink’s flying squirrel (Hylopetes platyurus)

Abstract

This study describes the anatomy and histology of the tongue in the Jentink’s flying squirrel (Hylopetes platyurus), a
rodent native to Indonesia (Borneo and Sumatra). We examined the characteristics of the tongue using scanning
electron microscopy (SEM) and light microscopy (LM). Macroscopic observations revealed three distinct regions: the
apex, corpus (body) and radix (root). The dorsal surface of the apex was characterized by a median groove and lacked
the lingual prominence that is common in many rodents. SEM and LM revealed the distribution of papillae over the
dorsal surface of the tongue. The papillae could be categorized as mechanical papillae (filiform, conical, large conical)
and gustatory papillae (fungiform, foliate, and vallate). Filiform papillae covered the apex and the anterior two-thirds
of the corpus. Fungiform papillae were distributed among the filiform papillae from the apex to the corpus, whereas
the foliate papillae were present only on the apex. Conical papillae were located on the posterior of the corpus, and the
large conical papillae were on the lateral surface of the lingual radix. Three vallate papillae were arranged in a "V"
pointing toward the larynx on the posterior part of the radix. This research provides the first detailed observations of
the lingual papillae in Hylopetes platyurus. The shape, structure and distribution of papillae are described and compared
with those in other rodent species.