Meeting Abstract
79.3 Sunday, Jan. 6 Functional Consequences of Morphological differences in Stingray Lateral Line and Electrosensory Systems JORDAN, L.K.; Univ. of California, Los Angeles ljordan@ucla.edu
How well can form predict function in sensory systems? Elasmobranchs demonstrate remarkable sensory capabilities with high interspecific diversity, particularly in the mechanosensory and electrosensory systems of batoids. These systems allow elasmobranches to detect water movements and electrical fields respectively. This study compares sensory anatomy and detection capabilities of the lateral line and electrosensory systems in the benthic round stingray, Urobatis halleri, benthopelagic bat ray, Myliobatis californica, and the pelagic stingray, Pteroplatytrygon violacea. Predictions based on detailed sensory anatomy maps were tested in behavioural detection experiments. U. halleri feeds primarily on small epifaunal benthic invertebrate prey and the lateral line of this species shows a high proportion of ventral non-pored canals while the electrosensory pores are highly concentrated around the mouth. M. californica, which feeds primarily on infaunal benthic invertebrates, has extensive and highly branched pored lateral line canals and a high electrosensory pore number and density highly concentrated anteriorly. Both systems in M. californica have dramatic lateral extension toward the wing tips on anterior edges of the pectoral fins. P. violacea feeds primarily on squid and teleost fish, and has an intermediate proportion of pored and non-pored canals with little branching of pored canals and a significantly reduced electrosensory pore number and density. Responses of each species to water jets and electrodes are compared. M. californica responds to water jets at a higher rate over a significantly greater proportion of its disc width. Responses to weak electrical fields were comparable to those observed for sharks with minimum responses below 1 nanovolt per cm. Ecological and evolutionary implications of these results are discussed.
