Hatching in two monogenean parasites from the common dogfish (Scyliorhinus canicula): the polyopisthocotylean gill parasite,Hexabothrium appendiculatumand the microbothriid skin parasite,Leptocotyle minor

Abstract

The common dogfish (Scyliorhinus caniculaL.) is caught regularly at Plymouth and is parasitized by two monogeneans, the gill-parasitic polyopisthocotyleanHexabothrium appendiculatum(Kuhn, 1829) Nordmann, 1832 and the skin-parasitic microbothriidLeptocotyleminor (Monticelli, 1888) Gallien, 1937. Unsuccessful attempts have been made to hatch the larvae of both of these parasites, e.g. Euzet (1957) and Wiskin (1970) forH. appendiculatum, and Llewellyn (1963) and Kearn (1965) forL. minor. Euzet (1957) and Kearn (1965) found that larvae developed within the eggs ofH. appendiculatumandL. minorrespectively but that these larvae failed to hatch.