First report of Temnocephala haswelli (Platyhelminthes: Temnocephalida) in Pomacea canaliculata (Mollusca: Ampullariidae) from Brazil: description update based on specimens from the state of Rio Grande do Sul, Brazil

The impact of the discovery of Temnocephala haswelli Ponce de Léon, 1989, described as ectosymbionts of ampullariid apple snails outside of Uruguay, motivated us to collect a large number of specimens of Pomacea canaliculata (Lamarck, 1822) from several localities in the southern portion of the state of Rio Grande do Sul. This species was recorded three times after its description: in a study of chromosomes, in a study about the ultrastructure of the collar receptor cells, and in a study of the Haswell glands, all conducted in Uruguay. A total of 301 specimens of P. canaliculata were collecte...