Spatiotemporal distribution and population structure of Clibanarius symmetricus (Randall, 1840) (Crustacea, Diogenidae) in an Amazon estuary

Authors: ANA CAROLINA MELO RODRIGUES, JUSSARA MORETTO MARTINELLI-LEMOS

Abstract: Rocky outcrops in the intertidal zones of estuaries often contain a highly diverse microbenthic community which includes the hermit crab, Clibanarius symmetricus, an abundant species on the equatorial Amazon coast. However, the ecology of this anomuran is poorly understood. Given this, the present study investigated the spatiotemporal distribution and structure of the C. symmetricus populations that inhabit the rocky outcrops of the Marapanim estuary in northern Brazil. Samples were collected monthly over a yearly cycle covering both the dry and rainy seasons in the upper and lower midlittoral zones during low tide. The distribution and abundance of C. symmetricus were affected directly by environmental factors such as temperature, seasonality, the intertidal zone, and salinity. The population presented sexual dimorphism, with males being larger than females, a male-biased sex ratio (1.5:1), a nonnormal and unimodal distribution, continuous reproduction, and sexual maturation at a cephalothoracic shield length of 3.6 mm. Despite the unique characteristics of the Amazon coast and the study estuary, the spatiotemporal distribution and structure of the C. symmetricus population were similar to those recorded at higher latitudes.

Keywords: Abundance, Anomura, macrobenthos, sex ratio, size classes

Full Text: PDF