Variations by sex in anatomical and morphological features of the tongue of Egyptian goose (Alopochen aegyptiacus)

Abstract

Tongue specimens were collected from 18 healthy adult Egyptian geese (Alopochen aegyptiacus) of both sexes. We measured and analyzed the whole, anterior, middle and posterior length and width of the tongue parts. The dorsal mucosal surface of each tongue was investigated by SEM. The length of whole tongue, widths at anterior and middle ends of its root showed significant differences between sexes. By gross morphology, the tongue showed 3 parts (anterior, middle and posterior). The anterior part represented 1 half of the tongue, while the 2 remaining parts comprised the other half. A clear median longitudinal groove was observed macroscopically along the forward half of the anterior region. The caudal part of the body had a central circular depression in front of giant conical papillae arranged in transverse row. On both sides of the tongue, cylindrical lingual papillae were compactly distributed and divided into anterior and posterior groups which increased in size and decreased in number caudally. By SEM, both giant conical and large cylindrical lingual papillae were lined with extensively modified mucosal surfaces that appeared as finger-like projections with scales. The tongue, which plays an important role in food intake in Egyptian geese, exhibited significant morphological variations in dorsal mucosal lining between sexes. Morphological observations recorded significant gender differences in total length and widths of the tongue at anterior and middle segments of its root.