Native
Ceratothoa steindachneri is an ectoparasite of the Lesser Weever Fish (Echiichthys vipera (Cuvier)), inhabiting the buccal cavity of its host. It is between 15 and 23 mm in length with an oval body shape and recurved sharp dactyls. The head is immersed in the first pereonite and the basal articles of the antennae are expanded so that they touch each other. The coxae are rounded and are not extended.
Ceratothoa steindachneri has been found in the buccal cavity of the Lesser Weever Fish (Echiichthys vipera (Cuvier)) in Cornwall (where it was first recorded in Britain), in the Thames Estuary (including at Isle of Grain in Kent), and at Les Minquiers in the Channel Islands, and appears to be spreading (Horton & Okamura 2002).
Horton, T. 2000. Ceratothoa steindachneri (Isopoda: Cymothoidae) new to British waters with a key to north-east Atlantic and Mediterranean Ceratothoa. Journal of the Marine Biological Association of the UK 80, 1041-1052.
Horton, T. & Baillie, C. 2019. Cymothoid isopods in UK Waters. PMNHS Bulletin 11, 44-50.
Horton, T. & Okamura, B. 2002. The distribution of Ceratothoa steindachneri (Crustacea: Isopoda: Cymothoidae) parasitic in Echiichthys vipera in the north-east Atlantic. Journal of the Marine Biological Association of the UK 82, 415-7.
Naylor, E. & A. Brandt. 2015. Intertidal Marine Isopods. Synopses of the British Fauna (New Series), No. 3. Field Studies Council, for The Linnean Society of London.
World Register of Marine Species (WoRMS): https://www.marinespecies.org/aphia.php?p=taxdetails&id=118874
Aphotomarine: https://www.aphotomarine.com/isopoda_ceratothoa_steindachneri.html
Ocean Biodiversity Information System (OBIS) distribution map: https://mapper.obis.org/?taxonid=118874
