Peculiar Labial Duct in the Camel Philtrum: Structure and Feasible Functions

Abstract

The philtrum is well known as a median groove within the upper lip of mammalian species. However, a peculiar serpentine duct was identified within the mucosal surface of the camel philtrum. To the best of the author’s knowledge, the available literature did not mention any information regarding the presence of a complete duct in such location. For these, this study was aimed to reveal the gross and microscopic structure as well as to discuss the possible functions of this labial duct in dromedary. Twenty snouts from 20 camel heads were used. The labial duct had unique morphological and microscopic structure. It was a median highly tortuous duct with proximal and distal segments connected to each other through a capillary portion. The latter revealed only at the microscopic level. The duct had two entrances, the proximal and distal papillae. Importantly, the microscopic studies revealed that it also had an olfactory portion. In conclusion, the labial duct in camels is a peculiar anatomical structure, which may function as an organ of alarm.