Comparative Morphological Studies on the Oropharyngeal Roof of the Adult Little Owl and Domestic Pigeon.

Abstract

The current study aims to compare the morphological features of the oropharyngeal roof of the little owl (Athene noctua) and the domestic pigeon (Columba livia domestica) by gross anatomy, morphometric measurements, scanning electron microscopy, and light microscopy. Ten heads of normal, healthy, and adult little owls and domestic pigeons were used in the current study as follows: seven heads for gross anatomical examination and light microscopy, and three for scanning electron microscopy. The oropharyngeal roof had a triangular appearance in both birds, was enlarged and broad in the little owl, and narrowly elongated in the domestic pigeon. The little owl had a median longitudinal ridge, a transverse ridge, and two lateral longitudinal ridges, while the domestic pigeon had one median and two lateral ridges. The choanal slit in both birds was composed of rostrally narrow and caudally wide parts. In the little owl, the edges of both parts were encircled by papillae, while in the domestic pigeon, the papillae encircled the edges of the rostral part only. The surface of the pharyngeal roof in the little owl had numerous elongated conical pharyngeal papillae, while that of the domestic pigeon was devoid of papillae. The edges of the infundibular cleft in the little owl had prominent large conical papillae, while those in the pigeon were devoid of papillae. Histologically, the epithelium of the plate and pharynx of both birds was composed of stratified squamous epithelium. In conclusion, the present study clarified several differences between the oropharyngeal roof of the little owl and the domestic pigeon, which reflect their adaptation to their feeding habits and the surrounding environments.