Gross anatomical and scanning electron microscopic studies of the oropharyngeal cavity in the European magpie (Pica pica) and the common raven (Corvus corax)

Abstract

There is no descriptive information about morphology of the oropharyngeal cavity including tongue, palate, and laryngeal region in Corvidae family. This study not only presents the first definitive anatomical description of the structures in the oropharyngeal cavity of magpie and raven but also reviews and compares the scattered information on the morphology of the other avian species available in the literature. In this study, the organs of four birds (two magpies and two ravens) were used. The tongue in magpie and raven was considerably elongated and terminated with an oval-shaped apex. Although the lingual apex in the magpie was divided by fissure, no such bifurcation existed on that of raven. Lingual apex was quite distinctive in both species, and multiple acicular processes covered the apex. These occurrences on the tongue of magpie were replaced by thread-like processes as approaching the lingual body. In raven, these processes were mostly foliated, becoming longer toward the back of the lingua, and denser compared with raven. Moreover, we observed conical papillary crest, which was pointed backward and located between the lingual body and the radix of the tongue and pharyngeal conical papillae around the glottis and palate clefts in both species. There was a transversal fold separating the choanal cleft from the infundibular cleft in raven. Anatomy of the oropharyngeal cavity in the raven and magpie, which are the member of the same family, Corvidae, showed little differences and overall their oral morphological features were excessively similar.