The freshwater crab Trichodactylus petropolitanus (Goeldi, 1886) (Decapoda, Trichodactylidae) associated with roots of Hedychium coronarium Koenig (Zingiberacea)

Abstract

This study analyzed aspects of the biology of the freshwater crab Trichodactylus petropolitanus from a population inhabiting a small montane stream in the Atlantic Forest (23o10́37́́S and 45o41́28́́W), located in the city of Caçapava, state of São Paulo, Brazil. Sampling was carried out monthly from February 2003 to January 2004, always during the day. The animals were found in association with roots of Hedychium coronarium, an invasive alien aquatic macrophyte. Juvenile (unsexed animals) and young crabs were dominant in the samples, while adults were rare. No ovigerous females or females brooding young were recorded. The analysis of relative growth showed that females reach morphological maturity at a smaller size than males. Analysis of the size-frequency distributions indicated that females grew faster than males. These differences may be related to the reproductive strategies of freshwater crabs. Our findings indicate that H. coronarium is used as a microhabitat by juveniles of T. petropolitanus along stream borders in remnants of the Atlantic Forest.