Meeting Abstract

P3.81  Wednesday, Jan. 6  Evolution of fin size and morphology in otophysan fishes RADE, CM*; WARD, AB; Adelphi University; Adelphi University cristinarade@gmail.com

Highly elongate body forms are found in most major groups of vertebrates. Body elongation in tetrapods has often resulted in the reduction or loss of the pectoral and pelvic girdles. Few studies have focused on whether there is a correlation between body elongation and reduction or loss of the paired fins in fishes. In this study, the relationship between body shape and fin size and morphology in otophysan fishes was examined. Morphometrics of the body and fins from 33 species including members of Characiformes, Cypriniformes, Gymnotiformes, and Siluriformes were collected. Fin anatomy from two species: the deep-bodied Carassius auratus and the highly elongate Apteronotus albifrons, was described in order to determine whether fin reduction is correlated with a more simplified musculoskeletal anatomy. All of the species included had pectoral fins, with the exception of Channallebes apus. Nine species did not have pelvic fins and those species without pelvic fins were significantly more elongate than species with pelvic fins. With regard to reduction of paired fins, it was found that body elongation was negatively correlated with length and width of the pectoral fins, but not the pelvic fins. Surprisingly, the musculoskeletal anatomy of the pectoral fin was more complex in the elongate knifefish, which has reduced fins. It is likely that the increase in number of fin muscles is associated with fin use during locomotion. This work will provide an understanding of how fin size and anatomy differs among related species that range in body elongation.