Habitat and life's story of Pachychelles laevidactylus (Crustacea, Anomura, Porcellanidae) in the rocky shore of Mar del Plata, Argentina

Abstract

Habitat structure, relative growth, the heterochely, population structure, morphometric maturity and fecundity of Pachycheles laevidactylus Ortmann, 1892 were analyzed during April, May and June 2005, in natural substrates of Mar del Plata, Argentina (38°02'S, 57°31'W). Algal cover, wave exposure and immersion time varied significantly between strata and between months. Chelae morphometry showed no differences between sexes. Females showed the greatest abdomen. While there was the heteroquelia, laterality not detected. The size (carapace width) ranged from 0.67 mm to 9.3 mm for males and from 1.07 mm to 10.65 mm, for females. The density of organisms varied among months and between strata. The population structure for the period of study explained depended on habitat structure. The morphometric maturity of females was recorded at the 4.38 mm of carapace width. The number of eggs was positively correlated with the size of the gravid females with a minimum of 2 eggs and a maximum of 160, but that relationship depended on progress in the development of embryos.

Keywords
Life history traits; population structure; intertidal; morphometry