Morphology and life history of Petasiger variospinosus (trematoda: echinostomatidae) in the Free State, South Africa.

Specimens of the freshwater snail Bulinus tropicus (Krauss, 1848) collected in the Free State, South Africa shed cercariae with an oral collar bearing 27 spines. Tadpoles of the African clawed toad Xenopus laevis laevis Daudin, 1802 collected from the same waters harbored metacercariae with a similar collar of spines. Adults were obtained after feeding infected tadpoles to laboratory-reared reed cormorants, Phalacrocorax africanus (Gmelin, 1789). The parasite was identified as Petasiger variospinosus (Odhner, 1910), the life cycle was experimentally completed, and stages described by the use of light and scanning electron microscopy.