Morphological descriptions of the lingual apparatus in the western cattle egret (Bubulcus ibis): Functional Adaptations to Feeding Behavior

The present study investigates the gross anatomy and microscopic structures of the tongue and its associated structures in the western cattle egret with the help of stereomicroscopy, light microscopy and scanning electron microscopy (SEM). This work was performed on ten heads of healthy adult cattle egret. These birds were trapped from different fields in Qena Governorate. Grossly, the tongue was a narrow elongated organ carrying a markedly pointed tip that did not extend to the anterior limit of the mouth cavity. The SEM revealed that the dorsal lingual surface was corrugated and exhibited many longitudinal microridges, which were separated by longitudinal microgrooves. The dorsal surface of the lingual root contained numerous openings of the ducts of glands. Histologically, thick keratinized stratified squamous epithelium lined most of the dorsum of the tongue, except its caudal part was non-keratinized type with intraepithelial mucous glands. The lingual salivary glands were two groups located lateral to the entoglossum and they occupied most of the lingual submucosa, especially at the base of the tongue. The cells of the glands reacted positively with PAS. Our conclusion highlighted that the tongue structures are uniquely adapted to their specific function in one of the most prevalent insect-eating bird species in Egypt.