Morphology features and microanatomy of the tongue papillae of the Eonycteris spelaea: Scanning electron microscopy and light microscopy.

Background: Eonycteris spelaea (E. spelaea) is a sizable nectar-feeding bat that falls within the taxonomic classification of order Chiroptera and family Pteropododae. The form and structure of the tongue play a crucial role for bats in the intake and digestion of food in their mouth. Each papilla's morphology, dimensions, spatial arrangement, and physiological role exhibit variations among different animal species, contingent upon their respective lifestyles.

Aim: This research attempts to examine the morphology and microstructure of the E. spelaea tongue papillae, collected from Timor Island, East Nusa Tenggara, Indonesia.

Methods: This study aimed to achieve a scanning electron microscope and a light microscope in the presence of hematoxylin-eosin staining and employed a sample of 6 sexually indiscriminate adult E. spelaea bats.

Results: The tongue of E. spelaea is separated into three distinct parts: the apex, corpus, and radix. The structure's apex contains filiform papillae, which come in many varieties, such as scale-like filiform papilla, enormous trifid papilla, and little crown-like papilla. Additionally, there is a cluster of fungiform papillae on the outside edge of the highest point and transitional papillae connecting the large trifid papillae with the smaller crown-like papillae. The corpus section comprises two papilla types: filiform papilla (leaf-shaped filiform papilla and big crown-like papilla) and fungiform papilla. The radix comprises the elongated conical papilla, rosette-shaped filiform papilla, short conical papilla, transitional papilla, and three circumvallate papillae at the back of the tongue.

Conclusion: The tongue papillae of E. spelaea comprise a wide variety of mechanic papillae and also sensory papillae which have specific dietary regimens in their living habitat.