JORDAN, L.K.; Univ. of California, Los Angeles: Ecomorphology of Stingray Mechanosensory and Electrosensory Systems (Elasmobranchii: Batoidea)
Elasmobranch fishes (sharks, skates, and rays) demonstrate remarkable sensory capabilities which are used for a variety of purposes including locating and capturing prey. This study relates the feeding ecology of stingray species representing the benthic, benthopelagic, and pelagic habitats to the anatomy of their mechanosensory and electrosensory systems. These systems allow elasmobranchs to locate prey by detecting water movements and electric fields respectively. Elasmobranchs are widely considered opportunistic generalist feeders, though some species exhibit dietary specialization. Existing literature on the stomach contents of three species, Urobatis halleri, Myliobatis californica, Dasyatis (Pteroplatytrygon) violacea, is compared to species abundance data from the same locations to identify selective feeding on certain prey. Morphometric measurements and detailed maps of sensory anatomy were constructed and analyzed for each species. U. halleri is a benthic ray feeding primarily on small epifaunal benthic invertebrate prey. The lateral line of this species shows a high proportion of non-pored ventral canals while the electrosensory pores are concentrated ventrally around the mouth. M. californica is a benthopelagic ray, capable of utilizing both benthic and pelagic environments, which feeds primarily on deeply buried infaunal benthic invertebrates. The lateral line system is highly branched with a large number of pores per branch which may help it locate water jets from the siphons of buried prey. D. violacea is a pelagic ray typically caught in the upper 100m in coastal waters. D. violacea feeds on highly mobile fishes and invertebrates, primarily squid. The lateral line branching and ratio of pored to non-pored canals is intermediate in this species. Relationships between the ecology of these three species, including their habitat and prey, and sensory morphology are explored.
