Oswaldotrema nacinovici gen. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil A new genus, Oswaldotrema gen. Differentiation from the other related genera, namely Philophthalmus, Pygorchis, Proctobium, Parorchis, Echinostephila, Cloacitrema, Pittacium, Ophthalmotrema, Skrjabinovermis and Paratrema , was based on morphological characters, mainly on those referring to the body surface, body shape, head, esophagus, pharynx, acetabulum, vitellaria, vitelline reservoir and seminal vesicle.
Measurements are in micrometers, unless otherwise stated.
Photomicrographs were obtained in a Zeiss mod. Axiophot system and the figure was achieved with the aid of a drawing tube connected to an Olympus CBA brightfield microscope. Acetabulum in middle third of body, nearly equatorial. Testes juxtaposed, lobed, just posterior to germarium, between the two cecal ends. Cirrus sac small.