Revalidation of Saccocoelioides bacilliformis (Digenea, Haploporidae) parasitizing species of Astyanax (Characiformes, Characidae) from southern Brazil

ABSTRACT In Argentina, Saccocoelioides bacilliformis Szidat, 1973 was described from specimens collected probably in Astyanax bimaculatus (Linnaeus, 1758), but latter it was synonymyzed with Saccocoelioides octavus Szidat, 1970. During the examination of digenetic trematodes collected in different species of Astyanax Baird & Girard, 1854 from southern Brazil, we found specimens identified as Saccocoelioides. A detailed comparison of the morphology of the two species revealed that they should be considered valid, thus this study proposes the revalidation of S. bacilliformis. The traits that allowed the revalidation were: body shape, position of the caecal bifurcation, and the extension of the uterus and vitellarium. Parameters of infections are provided for the first time in addition to records of new hosts and new locality.