Additional UK records of the non-native prawn Palaemon macrodactylus (Crustacea: Decapoda)

Since the discovery of the non-native prawn Palaemon macrodactylus in the Orwell estuary in December 2001, the species is now reported from other estuaries in the greater Thames area: Stour, Medway and Thames. A specimen from archived samples from the Thames is now the earliest European record (1992) but the original site and date of introduction into Europe and Britain remains unknown. Competition with the native P. longirostris is a possibility and biologists and naturalists are advised to check prawn specimens from current and archived samples collected from any British or European estuary for P. macrodactylus.