Meeting Abstract
Several lineages of teleost fishes have evolved ventral adhesive organs that allow adhesion to substrates. The superfamily Cyclopteroidea contains two families with such organs, the Cyclopteridae (lumpsuckers) and the Liparidae (snailfishes). In both families, the adhesive organs are hypothesized to be modifications of the pelvic girdle and fins. Descriptions of the myology of the ventral adhesive disk is lacking in snailfishes. An account of the myology of the adhesive organ can provide insights into how the adhesive organ functions and allows morphological comparisons that should suggest how these structures evolved. This study provides accounts of the myology of the ventral adhesive organ of several species of the genus Liparis. Data was obtained by manual dissections and by microCT scanning specimens stained with PMA (phosphomolybdic acid) for soft tissue definition. In Liparidae, the adhesive organ is built on the basipterygium, that form the base of the pelvic girdle. Its two halves articulate with five laterally expanded fin rays and one spine each. The intrinsic musculature of Liparis has bifurcated muscle groups present on the dorsal and ventral sides of the basipterygium. On either side, these muscles originate on the dorsal region of the basipterygium and insert on the same side of the dorsal surface of each fin ray. A relatively larger muscle originates on the antero-ventral edge of the basipterygium and inserts on the dorsal side onto the dorsal surface of the first fin ray. This muscle is proposed to be homologous to the muscle abductor profundus pelvicus found in other percomorphs. Comparisons with the adhesive organ of the lumpsucker, Eumicrotremus orbis, and with pelvic fins of few species of Cottidae will be presented and discussed.
