Meeting Abstract

38.3  Sunday, Jan. 5 08:30  Morphology and ontogeny of multiple lateral line canals in the prickleback genus Xiphister (Cottiformes: Zoarcoidei: Stichaeidae) CLARDY, T*; HILTON, EJ; VOGELBEIN, WK; Virginia Institute of Marine Science tclardy@vims.edu

Several members of the prickleback family Stichaeidae have multiple, complexly branching trunk lateral line canals that are supported by small, dermal, ring-like ossifications. Multiple lateral lines are rare among teleostean fishes and are found in representatives of only twelve other families. In this study, we examined the morphology and ontogeny of lateral line canals in the prickleback genus Xiphister. Both species in the genus, X. mucosus and X. atropurpureus, develop three paired, branching lateral line canals along the length of their body, plus a short, mediodorsal canal that extends from the neurocranium to the dorsal fin origin (canals 1-4 in dorsal to ventral sequence). Canals 1 and 2 develop rostro-caudally at 30mm, followed by canal 4 caudo-rostrally at 38mm, and, finally, by canal 3 rostro-caudally at 40mm. Trunk canals 1 and 2 connect to the cephalic sensory canals, which feature branches radiating from the infraorbital bones that also are supported by ring-like ossifications as found on the trunk. Canal 4 develops a short loop around the abdomen, and the left and right sides are connected by a short, anterior medioventral extension. The distribution of neuromasts, the sensory components of the mechanosensory lateral line system, was examined using histology. Canal neuromasts were observed in all of the cephalic canals and trunk canals 2 and 3. Canals 1 and 4, while similar in structure to other canals, lacked neuromasts and therefore cannot serve a sensory role in Xiphister. The functional role of multiple lateral line canals in Xiphister and other members of Stichaeidae warrants further investigation.