Relative growth of the male major chela and the female abdomen was studied in a population of the fiddler crab Uca maracoani from Baixio Mirim, Guaratuba Bay, in the municipality of Guaratuba, Paraná State coast, southern Brazil. The male handedness was also analyzed. Major chela length (CMQ) was measured from 486 males, and abdomen width (LAB) from 150 females. Furthermore, 67 crabs without secondary sexual differentiation were analyzed. Carapace width (LC) was the reference dimension for both sexes, which ranged from 3.36 to 34.15 mm for males, from 3.18 to 29.20 mm for females and from 1.27 to 4.82 for crabs without sexual differentiation. Relationship between CMQ and LC showed a transition point at 17.85 mm LC in males, and between LA and LC at 11.75 mm LC in females. Major chela had allometrically positive growth all the male life, while female abdomen had isometric growth in the early ontogenesis and allometrically positive after the puberal molting. These body dimensions are connected with reproductive activity of this species. The dactyl (range 0.82-38.15 mm long) growth in relation to major chela (range 1.36 to 52.35 mm long) was better explained by isometric relationship. The handedness had a proportion of 1:1 between right-handed and left-handed males.
Abdomen width; fiddler crab; major chela; Regrans
