Histology of parotoid gland of Anuran species Rhinella schneideri (Amphibia: Bufonidae)

Abstract

We performed histologic evaluation of the parotid glands of 10 (male and female) Rhinella schneideri. Animals were manually captured during nocturnal collections in Bom Jesus, Piauí, and euthanized by administering a lethal dose of anesthetic thiopental. The parotid glands were then collected and embedded in paraffin, and sectioned to 4 µm blocks using a manual rotary microtome. Considering the lack of general information concerning anatomical and histological conditions of Rhinella scheneideri, we sought to address key characteristics of macro glands found in the species with the goal of a better understanding of the operation of this type of defense mechanism. Histological analysis revealed the presence of macrogland alveoli with ducts encircled with differentiated mucous cells, known as "accessory glands", as well as granular glands. We also discovered glandular ducts on the glands which communicate with the outside of the body. These ducts are internally lined by duct glandular epithelial cells, forming a plug which promotes total obstruction of the duct. There were no histological differences in macro gland anatomy in this species compared to other species in Bufonidae.