New records of digenean parasites of Clarias gariepinus (Pisces: Clariidae) from the Okavango Delta, Botswana, with description of Thaparotrema botswanensis sp. n. (Plathelminthes: Trematoda)

Forty-two specimens of African sharptooth catfish Clarias gariepinus (Clariidae) were collected from a number of localities in the Okavango Delta in Botswana and examined for digenean parasites. The morphology of these parasites was studied using light and scanning electron microscopy. Six digenean species, four represented by adults and two by metacercariae, belonging to five different genera were collected from various organs within the fish. Clinostomoides brieni is described from the branchial chamber; a Neodiplostomum type metacercariae from the musculature; Phyllodistomum bavuri and Phyllodistomum vanderwaali from the urinary bladder; Glossidium pedatum from the intestine and one new species, Thaparotrema botswanensis sp. n. from the gall bladder. These are all new geographical records for southern Africa.