Parastenheliidae (Copepoda: Harpacticoida) from the Isles of Scilly

Three species of Parastenheliidae were found at a sampling site around low tide level on St Martin’s Flat in the Isles of Scilly. The most abundant species in the community was identified as Parastenhelia ornatissima but detailed study, particularly of the previously unknown male, indicates that this species has a sexually dimorphic antenna and belongs in the genus Karllangia as K. ornatissima comb. nov. Karllangia is re-diagnosed, K. tertia excluded from the genus; K. psammophila and K. bengalensis given specific status; Parastenhelia reducta placed incertae sedis in the genus and a key to species is provided. Five specimens (four being the previously undescribed male) of Parastenhelia anglica were found cooccurring with K. ornatissima. The species is redescribed; the P. anglica of Kunz from South Africa is shown to be the same as his Karllangia tertia and both these closely related species are placed in a new genus Foweya (as F. anglica comb. nov. and F. tertia comb. nov.) characterized by a sexually dimorphic inner spine on the P1 basis, no sexual dimorphism on the P3 endopod and the most primitive setal arrangement in the family. Also found at this site is Parastenhelia spinosa var bulbosa. This form has been raised to full specific status as P. bulbosa sp. nov. based on a detailed study of its anatomy which showed consistent differences with previous descriptions of P. spinosa from northwest Europe. It is suggested that, in the light of modern experimental, genetic and molecular techniques, the Langian concept of P. spinosa as a very variable, cosmopolitan species is probably erroneous and a thorough reappraisal of this species is needed.