Sexual system and Sexual dimorphism in the shrimp Arete indicus, symbiont with the sea urchin Echinometra mathaei in the Persian Gulf, Iran

Abstract

The sexual system and sexual dimorphism of the shrimp <em>Arete indicus </em>are described. The following were measured for all shrimp under stereomicroscope to the nearest ±0.01 mm: carapace length (CL), merus length (ML) and carpus length (CrL) of the largest of the first pair of chelipeds, pleural width of the second abdominal segment (PW), and propodus length (PL) of the second (larger) pair of chelipeds. Sex determinations were based on presence of the appendix masculina on the base of the endopod of the second pleopods. With a view to determine whether or not a linear relationship exists between the CL, PL, ML, CrL and PW, the allometric model y = axb was used. A correlation was found between CL and ML in both sexes of <em>Arete indicus</em>. The status of allometry differed among various body parts of both sexes, and degree of allometry differed among various body parts between the sexes. According to ANCOVA, PW, PL, and ML of females are not larger than that of males at any given body size .The CL of <em>Arete indicus </em>females was not larger than the males. Due to observation a few of males with tiny appendices masculina, also based on earlier literature worked on <em>Arete indicus</em>, we believe this species is partially protandric.