Meeting Abstract

S11.12  Wednesday, Jan. 6  Morphological Correlates to the Evolution of Elongation in Elopomorph Fishes MEHTA, R.S*; WARD, A.B; ALFARO, M.E; WAINWRIGHT, P.C; Univ. of California, Davis; Adelphi University; Univ. of California, Los Angeles; Univ. of California, Davis rsmehta@ucdavis.edu

Body shape has had profound effects on how organisms make their living. Long, slender body forms have evolved multiple times in teleosts and are associated with diverse behaviors such as undulatory locomotion, head-first and tail-first burrowing, and knotting around prey. Despite current interest in understanding the molecular, developmental, and anatomical basis for elongation, few studies have examined the diversity of elongation within a clade and what characters may be correlated with increases in vertebral number. Elopomorph fishes are an extremely diverse clade of teleosts that contain bone fish, tarpon and a large radiation of elongate and limb-reduced ‘true eels.’ A recent study revealed that at least two patterns of elongation have occurred in the Elopomorpha: an increase in caudal vertebrae with no increase in abdominal vertebrae and the converse. Here we use the Elopomorpha as a model for understanding the effects of elongation on morphology associated with feeding and locomotion. Using an elongation index, we examine 50 elopomorph taxa in an attempt to understand how characters such as head length, branchial arch displacement, and fin shape correlate with increases in vertebral number. Our preliminary results reveal that increases in vertebral number are correlated with head length but this relationship is not as strong as we anticipated. We also find a relatively weak relationship between branchial arch displacement and vertebral number. Lastly, using information from the literature, we will discuss how these morphological relationships relate to dietary breadth in Elopomorphs.