Relative growth of the mangrove crab Ucides cordatus (Linnaeus, 1763) (Crustacea, Brachyura, Ocypodidae) at Iguape, São Paulo, Brazil

Abstract

A total of 2,130 individuals of Ucides cordatus (1,255 males and 875 females) were captured in a mangrove forest at Iguape, São Paulo, Brazil. For each crab, the following body structures were measured: carapace (width = CW; length = CL; depth = CD), 5th abdominal somite (AW), major chelar propodus (length = PL; width = PW; depth = PD), and 1st and 2nd gonopod pairs (length = GL1 and GL2). The Student "t" and Snedecor "F" tests were used to verify any changes in growth allometric rates during ontogeny. The relationships CLxCW, PLxCW (for both sexes), GL1xCW and GL2xCW (males) and AWxCW (females), showed a better fit by two equations for the juvenile and adult phases (p<0.01). The inflexion point size between regression lines, indicated by each morphometric relationship, allowed to propose four morphotypes for U. cordatus. Males were classified in juvenile (CW < 32 mm), pre-puberty (32 < CW < 51 mm), sub-adult (51 < CW < 59 mm) and adult (CW > 59 mm). Females showed a similar size interval: (juvenile CW < 39 mm, pre-puberty 39 < CW < 53 mm, sub-adult 53 < CW < 58 mm, adult CW > 58 mm).