Shell morphology variation and population density of Littoraria angulifera (Mollusca: Gastropoda) in mangrove forests of Ceará State, Brazil

Abstract

The morphology of gastropod shells varies considerably among different habitats is possible to relate the shape or size of the shell with different environmental conditions. The objective of this paper was to study the Littoraria angulifera distribution in mangroves, checking for differences in shell size or density population, and to test the existence of patterns zonation. Individuals were collected from nine estuaries of the Ceará coast. In each place, three sites were chosen and each area was marked by transects of five shares measuring 10m2 . In each plot we identified the mangrove vegetation species, obtained data of structure and collected L. angulifera specimens, which subsequently had the size measured. Four mangrove species were found: Avicennia germinans, Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle, the latter being dominant in most estuaries. The structural parameters varied among the mangroves. The values of the shell size were positively correlated with height and basal area of tree, DBH and density. There was no significant difference in shell size or density of organisms along the zonation gradient tested. The variation in size and density indicate that individuals recognize and respond to different microhabitats.