Meeting Abstract

P3.73  Thursday, Jan. 6  The Morphology of the Free Portion of the Tongue in a Nectar-Feeding Bat, Glossophaga soricina HARPER, C.J.*; BRAINERD, E.L.; SWARTZ, S.M.; Brown University, Providence; Brown University, Providence; Brown University, Providence caroline_harper@brown.edu

During feeding, Glossophaga soricina extend their long tongues into a flower and use brush-like papillae at the tongue tip to collect nectar. The mechanism of tongue elongation can be described using the muscular hydrostat model, which states that orthogonally arranged muscle fibers within the tongue decrease its diameter, causing a corresponding increase in tongue length. However, previous research identified enlarged lingual vessels within the tongue and proposed that muscle contraction and blood flow act together to elongate the tongue. The goal of this study was to investigate the anatomy of the muscles and lingual vessels along the length of the tongue in G. soricina to gain insight into the likely role of the vessels in tongue elongation. The tongues from two G. soricina were serially sectioned in multiple orthogonal body planes and stained with hematoxylin and eosin. Micrographs show three distinct, orthogonally arranged muscle fiber populations within the tongue: the vertical, longitudinal, and horizontal muscle bundles. Contraction of these muscle fibers may decrease the tongue’s diameter, causing a corresponding increase in tongue length. Near the base of the tongue, the lingual vessels diverge into smaller branches. These smaller vessels extend to the tongue tip and are located within the center of each papilla. The location and trajectory of these vessels suggest that blood flow may inflate the brush-like papillae. These findings support both models of tongue elongation such that muscle acts to elongate the tongue and blood flow is used to inflate the papillae and increase the surface area of the tongue during feeding.