Capybara (Hydrochoerus hydrochaeris) Salivary Glands Morphology

Abstract

Morphological studies concerning salivary glands have emerged as an exciting tool to understand feeding habits. In this sense, this study aimed to describe capybara salivary glands morphology to understand potential morphological associations to this species feeding habits. Macroscopic dissections and microscopic analyses were performed on eight specimens. The findings indicate that capybaras have three pairs of major (parotid, mandibular and sublingual) and two pairs of minors (dorsal and ventral buccal) salivary glands. The parotid gland, the largest, is irregularly shaped, forming small macroscopic lobes. The mandibular gland is rounded and found syntopically alongside the mandible angle and arranged medially to the ventral projection of the parotid gland. The sublingual gland is a compact elongated and semicircular mass. The dorsal and ventral buccal glands are located in the buccal portion of the buccinator muscle. Histologically, the parotid and mandibular glands are composed of serous acini, while the sublingual and buccal (dorsal and ventral) glands consist of mucous tubules containing serous demi-lunes at their periphery. Capybara salivary glands reveal morphological associations with a predominantly herbivorous diet. The parotid gland, for example, notably developed in size and volume, suggests a specialisation for increased saliva production, necessary for chewing, forming the food bolus, swallowing fibrous foods, and protecting the oral cavity ecosystem.