Meeting Abstract
Gobies (Family Gobiidae, the largest family of marine fishes) have a complex mechanosensory lateral line (LL) system comprised of reduced cranial and trunk canals and a proliferation of small superficial neuromasts (SNs), which are perched on the tips of papillae (“sensory papillae”; bump-like extensions of the skin) that occur in linear series. The LL system in Elacatinus lori, a sponge-dwelling goby from Belizean coral reefs is composed of a moderate number of SNs (~300 on one side of the head, trunk and tail) when compared to other gobies described in the literature (which may have 1000’s of SNs). The genus Elacatinus (21 species), found exclusively on coral reefs, is divided into three clades: a Pacific species (basal clade), coral-dwelling cleaner gobies, and sponge-dwelling planktivorous gobies. The large tube sponges in which the sponge-dwelling gobies live produce a constant flow of water within the lumen, where the gobies reside, creating a unidirectional flow stimulus to which the fish are continuously exposed. In contrast, different sorts of environmental flows are experienced by the coral-dwelling gobies. Using SEM, we tested the hypothesis that SN number, distribution, and papilla length in sponge-dwelling Elacatinus species (including E. lori) are different from those in coral-dwelling Elacatinus species; Tigrigobius, its sister group, was used as an outgroup. We predicted that sponge-dwelling gobies have fewer SNs and/or shorter papillae than coral-dwelling gobies, which would reduce overstimulation of the SNs that may occur under the constant flow conditions experienced within their host sponges. Funded by NSF grant 1459224 to JFW.
