Meeting Abstract

P2.57  Monday, Jan. 5  The gular glands of Alligator mississippiensis condition the interscale skin of the intermandibular and gular regions HOPKINS, B.A.*; HOMBERGER, D.G.; Louisiana State Univ., Baton Rouge; Louisiana State Univ., Baton Rouge bhopki1@lsu.edu

Crocodilians swallow prey items that are large relative to their body size. Swallowing large prey items requires an expansion of the pharynx and esophagus and, thus, an expansion of the intermandibular and gular skin. In the scaly skin of crocodilians only the soft interscale skin is stretchable and pliable, and, therefore, needs to be conditioned to maintain its physical attributes. In contrast to mammals, which condition their skin with sebum from numerous and dispersed integumentary glands, alligators have only three kinds of locally restricted integumentary glands, one which is a pair of gular glands. The gular glands have been thought to produce pheromones; however, their lipid secretion consists of many of the same components as those found in cosmetic skin care products. In the alligator, deep stretchable interscale skin grooves radiate rostrally from the orifice of the gular gland and interconnect with smaller stretchable interscale skin grooves in the intermandibular and gular regions. The interscale skin grooves form a network of hierarchically arranged channels of particular width and characterized by particular epidermal microstructures. The epidermal microstructure of the stretchable interscale skin grooves varies significantly from that of the less stretchable interscale skin in the abdominal region, but bears some resemblance to the microstructure of the channels that carry water from wet skin to the mouth of some desert lizards. We hypothesize that the stretchable skin in the intermandibular and gular regions of alligators serves not only to accommodate the passage of large prey items, but also to channel and distribute skin conditioning lipids from the paired gular glands.