In this note, we registered the occurrence of shell diseases and carapace abnormalities in a natural population of Neohelice granulata from a tropical mangrove forest, in South America, as a part of a wide ecological study. The occurrence of 32 adult crabs (1.77%) with black or brown spotted shells, or deformities on the carapace was registered, collected in the autumn and winter seasons. The low prevalence of shell diseases and abnormalities in this natural population is considered normal and probably caused by injuries occurring during the moult period of crabs.
