Histology of Rathke’s Glands in the Razor-backed Musk Turtle, Sternotherus carinatus (Chelonia: Kinosternidae), with Comments on Lamellar Bodies

Abstract

I examined the histology and ultrastructure of Rathke’s glands in two adult male razor-backed musk turtles (Sternotherus carinatus) collected in northeastern Arkansas. This species possesses two pairs of Rathke’s glands that are embedded beneath marginal bones and are named according to their anatomical location (i.e., axillary and inguinal). These integumentary glands are similar anatomically to one another. Each gland is comprised of a single, highly vascularized secretory lobule, which is surrounded by a thin tunic of asymmetrically arranged, striated muscle. Two types of large secretory vacuoles characterize most of the holocrine cells produced by a relatively thin secretory epithelium. My results suggest that the chief secretory material of the smaller dark-staining secretory vacuole is a glycoprotein complex. The larger, mostly translucent secretory vacuole contains variously sized, multilaminar, osmophilic lamellar bodies, whose structural design is reminiscent of an epidermal lipid delivery system in vertebrates. The function of Rathke’s glands in turtles remains unknown.