General morphology of the oral cavity of the Nile crocodile, <i>Crocodylus niloticus<i/> (Laurenti, 1768). I. Palate and gingivae

Abstract

The heads of nine 2.5 to 3-year-old Nile crocodiles (Crocodylus niloticus) were obtained from a commercial farm where crocodiles are raised for their skins and meat. The animals from which these specimens originated were clinically healthy at the time they were slaughtered. A detailed description of the macroscopic and microscopic features of the palate and gingivae of the Nile crocodile is presented and the results are compared with published information on this species and other Crocodylia. The histological features are supplemented by information supplied by scanning electron microscopy. Macroscopic features of interest are the small conical process situated at the base of the first two incisors of the maxilla, the distribution of cobbled units on the palate, and the broad dentary shelf forming the rostral aspect of the mandible. Histologically the palate and gingivae did not differ significantly from each other and both regions showed a presence of Pacinian-type corpuscles. Two types of sensory structures (taste receptors and pressure receptors) were identified in the regions examined, both involving modification of the epithelium and the underlying connective tissue.

Fine structure of the dorsal lingual epithelium in Tarentola annularis and Crocodylus niloticus

“…Taste buds were also seen to be concentrated in the thickened epithelium forming the surface opening of the lingual salivary glands. The morphology of the lingual taste buds was similar to that reported for taste buds in the palate and gingivae of the Nile crocodile [35,36] and reflects the features previously described by Bath [1] and Taguchi [48] in this region of the oral cavity. In some turtles the taste buds are missing [57] but they are scattered in the buccopharyngeal mucosa in other turtles [14].…”

Gross anatomy and scanning electron microscopic study of the tongue of Egyptian Dabb lizard (Uromastyx aegyptia) in relation to feeding habits

“…The latter two papillae presented on the hind-tongue surface were also detected on tongue surface of American alligator (Shimada et al, 1990)and Nile crocodile (Putterill and Soley, 2003). Otherwise, keratinization characterize of stratified squamous epithelium the lingual epithelial surface of Uromastyx aegyptia was also recognized in many reptiles such as lizard, Eumeces schneideri, Scincidae (Wassif, 2001) Lamina propria in the three parts of tongue of the present Uromastyx aegyptia which is formed of dense connective tissue is rich with blood vessels and striated muscle fibers appeared in different arrangement and density .The distribution and orientation of the muscle fibers prove that the tongue is able to catch the preys by its bifurcated tip.…”

Prenatal development of Crocodylus niloticus niloticus Laurenti, 1768

“…These numbers are similar to the adult tooth numbers. There have been documented 18 teeth (5 incisors, 5 canines and 8 molar teeth) in the upper jaw quadrant and 15 teeth (3 incisors, 5 canines, 7 molars) in the lower jaw quadrant of the adult Nile crocodile (Putterill and Soley, 2003).…”