Morphology of the Soft Palate Tonsil Mucosa of Collared Peccary (Pecari tajacu, Linnaeus, 1758)

Abstract

Collared Peccary (Pecari tajacu, Linnaeus, 1758) is a mammalian Tayassuidae species from tropical to semi-arid areas. The morphological features of the oral cavity in this species were identified and described. Tonsils are secondary lymphoid organs essential for contact with antigens due to food and air intake. This study aimed to describe histological characteristics and three-dimensional morphology of the soft palate tonsil mucosa. Therefore, the samples (n = 10) were analysed by stereomicroscope for morphology, light microscopy (n = 4) for structural characterisation, and scanning electron microscopy (n = 6) to reveal three-dimensional aspects of the epithelial surface and connective tissue cores (CTC). Our findings revealed a pair of soft palate tonsils separated by a median raphe. A keratinised squamous stratified epithelium characterised the tonsil. The epithelial surface had several orifices, and these were associated with a lymph nodule organisation. After epithelial removal, the three-dimensional aspect of the lamina propria was evidenced by conical projections throughout the region, even on the crypt's edge and inside them. The soft palate tonsils mucosa was like the previous description; however, the revealed CTC had a conical morphology, a new feature in this organ.