Extraoral Taste Buds on the Paired Fins of Damselfishes

Abstract

Synopsis Some fsh species have taste buds on the surface of their bodies and fns, as well as in the oral cavity. The extraoral taste system of fsh has traditionally been studied in species that inhabit environments and/or employ feeding strategies where vision is limited. Here we examined taste sensation in a new ecological context by investigating the paired fns of damselfsh (Pomacentridae), a group of diurnal midwater fshes that inhabit the light-rich waters of coral reefs. Immunohistochemistry demonstrated the presence of taste buds on the paired fns of Chromis viridis, including on the distal tips of elongate leadingedge pelvic fn rays, where they are particularly densely packed, suggesting specialization for chemosensation. Similar anatomical results were also recorded from two other species, Pomacentrus amboinensis and Pomacentrus coelestis. We found that a?erent pectoral fn nerves of C. viridis responded to a food-derived stimulus. By investigating the extraoral taste system in a new phylogenetic and ecological context, these results show that taste buds on fns are more widespread amongst fsh than previously known and are present even in highly visual environments.