A new trematode species parasitizing the catfish Hoplosternum littorale [Osteichthyes, Callichthyidae] from Parana River, Brazil, with an emendation of the diagnosis of Magnivitellinum [Trematoda, Macroderoididae]

Magnivitellinum corvitellinum sp. nov. is a parasite from the intestine of tamboatá Hoplosternum littorale, a freshwater catfish from Paraná River, Brazil. This species has an elongate body, a small cirrus-sac, testes in the posterior half of the body and well-developed follicular vitellines. It differs from the only other species in the genus, M. simplex, in having tegumental spines along the body, ventral sucker distinctly bigger than oral sucker, oesophagus absent and vitellaria extending from posterior margin of ventral sucker to near posterior extremity of body. An emendation of the generic diagnosis is proposed in view of the presence of tegumental spines along the body, absence of oesophagus, relative size of ventral and oral suckers and uterus covering caeca from the level of ventral sucker to the end of caeca. This is the fourth trematode species recorded parasitizing Hoplosternum littorale.