Fluorescent patterns in some Portunus species (Crustacea: Brachyura: Portunidae).

Portunus is a large genus of swimming crabs, which has been observed to have fluorescing patterns in certain species, including commercially important ones. We examined these patterns for their potential usefulness as a diagnostic character in species identification. Specimens of various Portunus species were photographed under normal light and UV light. It was observed that fluorescent patterns varied inter- and intra-specifically. The patterns were consistent between males and females of each species, but not amongst juveniles. Fluorescent colour patterns were most pronounced in fresh specimens, and may be useful as a complementary taxonomic character for species identification.