Tongue microarchitecture and functional characterization of the lingual papillae in the desert hedgehog (Paraechinus aethiopicus)

The present work attempted to provide a comprehensive description of
the morphoanatomical, histological, and ultrastructural characteristics of the
tongue in the desert hedgehog (Paraechinus aethiopicus), and to correlate lingual
modifications to the feeding lifestyle. Five adult male hedgehogs were utilized
in our investigation. The macroscopic observations revealed elongated, with a
moderately pointed apex, tongue and the tongue dorsum lacks both lingual
prominence and median sulcus. The main subdivisions of the tongue are radix
linguae (root), corpus linguae (body), and apex linguae (apex). The tongue
dorsum carries two types of mechanical (conical and filiform) and gustatory
(fungiform and circumvallate) papillae. The lingual apex is characterized by the
existence of a unique encapsulated muscular structure. Additionally, the lingual
glands were interposed between the muscular strands and no lingual glands
were detected on the lingual apex. The dorsal surface of the lingual apex
exhibited the highest level of keratinization as revealed by histochemical
staining while the root showed moderate staining. The topography of the
tongue was investigated by scanning electron microscopy (SEM). The obtained
results are important to provide basic knowledge that can contribute to better
understanding of the nourishment, feeding habits and behavior in this species.
Furthermore, the addition of the newly investigated species may help us to
determine the evolutionary relationships among species.