Comparative morphological study of the oropharyngeal floor of squabs and adult domestic pigeons (Columba livia domestica).

The current study compared the morphological features of the oropharyngeal floor of squabs and adult domestic pigeons (Columba livia domestica). Samples from the oropharyngeal floor of both squabs and adult pigeons were collected directly after slaughtering. The collected samples were examined grossly, morphometrically, and by scanning electron microscopy (SEM). The lower beak had triangular shape with pointed rostral end. The tongue did not fill the entire oral floor in squabs as well as adult pigeons. The lingual apex of squabs had a small lingual nail while that of the adult pigeons had a well-developed lingual nail. The lingual body was separated from the lingual root by a transverse papillary crest, which was "V" shaped in squabs but "U"-shaped in adult pigeons. Filiform papillae were distributed on the dorsal surface of lingual apex, as well as, body, but were absent on the root. The lingual root presented fine elevations and low projections in squabs and adult pigeons, respectively. On the other hand, the tongue of adult pigeons had larger number of the lingual salivary glands openings compared to that of squabs. In addition, the edges of the glottis had numerous small projections in squabs bur presented large dome-shaped papillae in adult pigeons. Moreover, adult pigeons had longer pharyngeal papillae at pharyngoesophageal junction than those of squabs. In conclusion, these variations suggest that adult pigeons adapted well to their diet, which might reflect higher efficiency of food prehension.