On the morphology and life-history ofMonascus[=Haplocladus]Filiformis(Rudolphi, 1819) Looss, 1907 andSteringophorus Furciger(Olsson, 1868) Odhner, 1905 (Trematoda, Fellodistomidae)

Abstract

The cercariae of Monascus [= Haplocladus] filiformis (Rudolphi, 1819) Looss, 1907 and Steringophorus furciger (Olsson, 1868) Odhner, 1905 (fam. Fellodistomidae) develop in the bivalves Nucula nitidosa Winckworth and Nuculana [= Leda] minuta (Müller), respectively. Both trematode species may only have two hosts without a stage of metacercaria. The large furcocercous cercaria of M. filiformis is eaten by dab Limanda limanda (L.) in which it matures. The cercaria may also be eaten by gobies, but it does not mature in these fishes. Horse mackerel Trachurus trachurus (L.) is infested by eating infested crystal gobies CrystaUogobius linearis (Düben). The large leptocercous cercaria of S. furciger is eaten by dab L. Limanda in which it matures. The cercariae of M. filiformis and S. furciger are redescribed, and the different developmental stages of both species were studied in the scanning electron microscope. Both species have a corrugated surface without spines. The cercaria and adult M. filiformis do not have a single unbranched caecum as previously described, but a long right caecum and a short, reduced left caecum. The bifurcation occurs between the ventral sucker and ovary. Monascus from dab M. minor (Odhner, 1911) and Monascus from horse mackerel cM. typicus (Odhner, 1911) are identical to M. filiformis. Previous records of Monascus spp. are given, and the possibility that only one species, M. filiformis, exists is discussed.