Nerocila orbignyi (Guérin-Méneville, 1832)


N. orbigny is an external parasite of fish which attaches itself with the recurved dactyls at the ends of its prehensile legs. It can be distinguished from Anilocra sp. by its prominent coxal plates, the posterolateral angles of pereonites 2-6 being extended, and by its head not narrowing at the front to form a projection between the antennae.

Distribution and Habitat

N. orbignyi has been found off the south coast of England as an external parasite on various fish, including Thick-lipped Grey Mullet, Mackerel and Herring. Unlike Anilocra sp., it typically attaches towards the rear of the fish.



Horton, T. & Baillie, C. 2019. Cymothoid isopods in UK Waters. PMNHS Bulletin 11, 44-50.

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.