Meeting Abstract

72.1  Thursday, Jan. 6  Convergent Evolution of an Adaptive Phenotype in the Mechnosensory Lateral Line System: It’s not that Simple WEBB, JW*; ALBERG, T; Univ. of Rhode Island; Univ. of Rhode Island jacqueline_webb@mail.uri.edu

The mechanosensory lateral line system of fishes plays critical roles in a variety of behavioral contexts including prey detection, predator avoidance, communication and navigation. Four types of cranial lateral line canal systems are found among teleost fishes (narrow, branched, widened, reduced). Widened canals are the most limited in their distribution and are found in representatives of only about a dozen teleost families living in benthic marine, mesopelagic, lacustrine and stream habitats. It has been suggested that widened canals evolved as an adaptation for detection of hydrodynamic disturbances generated by both midwater prey and infaunal prey living in soft sediments. If this is the case, can a precise set of morphological attributes of widened canals be defined that is the result of the convergent evolution of widened canals as a functional phenotype among diverse taxa? The morphology of widened canals and canal neuromast receptor organs within them in representatives of four teleost orders (Cypriniformes, Stephanoberyciformes, Perciformes, Pleuronectiformes) was studied using traditional morphological methods and microCT imaging. Relative diameter of the various cranial canals, uniformity of canal diameter along its length, canal pore size, % bone cover, and canal neuromast morphology were assessed. Results of this analysis and a review of the literature indicate that the definition of “widened canals” must be modified to encompass variation in both canal and canal neuromast morphology. As a result, the functional attributes of “widened canal” systems among diverse teleost taxa may not be easily generalized. Supported by NSF grant IOS-0843307 to JFW.