Stages of the life cycle of Ascocotyle (Phagicola) angeloi Travassos, 1928 were experimentally obtained, from cercariae from naturally infected Littoridina castellanosae (Gaillard) collected in artificial ponds in the Zoological Garden of Buenos Aires. Metacercariac were found encysted mainly in muscles and ovary, but also in other parts of the body of naturally and experimentally infected fish Jenynsia lineata (Jenyns) (Atheriniformes: Jenynsidae). Adults were obtained experimentally from chicks and mice. Ascocotyle (Phagicola) angeloi, rcdescribed in the present paper, is distinguished from other species of the subgenus by the two rows of oral spines, each with 14 spines. The characteristics of the studied cercaria corresponds to those of the subgenus Phagicola.
Holotype and paratype of Ascocotyle (Phagicola) rara Arruda, Muniz-Pereira et Pinto, 2002, a heterophyid trematode recently described on the basis of two worms collected by Lauro Travassos in 1921 in the intestine of Ixobrychus exilis (Gmelin) from Brazil, were studied. The morphology of the worms revealed their conspecificity with Ascocotyle (Phagicola) angeloi Travassos, 1928 found in the same host. Both the taxa have a similar length (between 600 and 900 µm) and shape of the body (long pyriform), the long intestinal caeca reaching to the ovarian level, a long posterior muscular prolongation of the oral sucker and the prepharynx, transverse uterine loops situated between the ventral sucker and testes, and the gonotyl with more than 20 digitiform pockets. Consequently, A. (P.) rara is proposed as a junior synonym of Ascocotyle (Phagicola) angeloi.