Cellular organization of visual neuropils of a highly visual crab revealed by reduced-silver methods.

JULIETA SZTARKER, NICHOLAS STRAUSFELD AND DANIEL TOMSIC

Inglaterra

Congreso; Gordon Conference in Neuroethology: Behavior, Evolution & Neurobiology; 2008

Gordon Research Conferences

Crustaceans are among the most extensively distributed phylogenetic groups, occupying many different ecologies and thus having very different lifestyles. However, compared with insects, relatively little is known about the neural organization and cell morphologies of crustacean optic neuropils. Although the overall organization of the visual nervous system can be safely generalized amongst decapod species, and to a considerable extent even between decapods and insects, the proposal that there is equivalence between the cellular elements that compose the neuropils of different species requires further support if it is to be justified. Published anatomical data on crustaceans relate almost exclusively to the first optic neuropil, the lamina, and suggest that laminas from different species comprise similar cell types. However, the question remains whether species that live in deep or turbid waters have visual neuropils organized like those living in shallow clear water or on land. Chasmagnathus granulatus is a semiterrestrial crab belonging to the grapsid family, members of which are acutely reactive to visual stimuli. At low tide these animals view clear air. At high tide they are immersed in turbid water and thus are subject to two very different visual environments. The present study investigates if such a dual habitat requires fewer or more cell types at the level of optic neuropils. Here we describe the cellular composition of the lamina showing both commonalties with previously described decapods in addition to novel elements that may possibly confer additional processing capacities to this type of crustaceans.