Ultrastructure of the submandibular gland of the rare white-winged vampire bat, Diaemus youngi.

The submandibular gland of the white-winged vampire bat, Diaemus youngi, was examined by electron microscopy. Unlike typical submandibular glands, those in Diaemus have only one type of secretory cell in their endpieces, namely, serous cells. These serous cells are conventional in structure, with an extensive rough endoplasmic reticulum, scattered dictyosomes, and numerous secretory granules. The endpiece lumina, as well as intercellular canaliculi, are fitted with numerous microvilli, which also are present on the otherwise unremarkable intercalated duct cells. Striated ducts are of conventional morphology, but have a brush border-like array of microvilli on their luminal surface. These cells resemble those in the submandibular gland of the common vampire bat, Desmodus rotundus. The presence of an abundance of microvilli in the salivary glands in the two vampire bat species (and their absence from chiropteran species that consume other types of diets) is a strong indication that these structures play a significant role in dealing with the problems posed by a sanguivorous diet.