Meeting Abstract

14.5  Monday, Jan. 4  Exploring the adaptive significance of morphological specializations of the pectoral fins among benthic scorpaeniform fishes TAFT, Natalia K.; University of Chicago taft.nk@gmail.com

Several groups of fishes use the pectoral fins for routine substrate contact and exhibit morphological specializations that have been hypothesized to be adaptive for a benthic lifestyle. Here I examine the relationship between pectoral fin morphology and a benthic lifestyle among the primarily benthic scorpaeniform fishes (sensu Smith and Wheeler, 2004). Evidence of correlated evolution between specializations of the pectoral fins and a benthic habitat can provide support for the hypothesis that these features are adaptive for bottom-dwelling. I examined pectoral fin morphology among 23 species from 15 scorpaeniform families. I identified three discrete characters of the pectoral fins that are associated with a benthic lifestyle: 1) an asymmetrical fin membrane among ventral fin rays, 2) the presence of fin rays that are unbranched distally and 3) the presence of ventral pectoral fin rays that are free of fin membrane. I tested for correlations between each of these characters and a benthic lifestyle using Pagel’s test of correlated evolution. Asymmetry of the fin membrane among ventral fin rays is marginally correlated with a benthic lifestyle. The presence of unbranched fin rays is not correlated with a benthic lifestyle in this group. Free pectoral fin rays are rare among the species I examined and not correlated with a benthic lifestyle. However, free pectoral fin rays are present only in benthic species. Each of the morphological specializations I examined evolved independently more than once among benthic scorpaeniform clades suggesting that these characters are adaptive for bottom-dwelling. Scorpaeniform fishes are very speciose; these results provide a jumping-off point for future analyses of pectoral fin morphology of the group as a whole as well as within individual clades.