Redescriptions of two echinostomes from birds in Paraguay, with comments on Drepanocephalus Dietz, 1909 and Paryphostomum Dietz, 1909 (Digenea: Echinostomatidae).

Two species of echinostomatid trematodes from Paraguayan birds are redescribed: these are Drepanocephalus spathans Dietz, 1909 from Phalacrocorax olivaceus and Paryphostomum segregatum Dietz, 1909 from Coragyps atratus. The genera Drepanocephalus Dietz, 1909 and Paryphostomum Dietz, 1909 are redefined and the species previously assigned to them reviewed. Paryphostomum mexicanum (Lamothe-Argumedo & Pérez-Ponce de León, 1989) n. comb. and P. parvicephalum (Rietschel & Werding, 1978) n. comb. are transferred from Drepanocephalus to Paryphostomum. A key to the species of Paryphostomum is presented, and the nominal species of Echinostoma Rudolphi, 1809, Nephrostomum Dietz, 1909 and Artyfechinostomum Lane, 1915 previously ascribed to this genus are commented upon. New combinations for species previously attributed to Paryphostomum are: Echinostoma pentalobum (Verma, 1936) n. comb.; E. baiyangdienense (Ku, Pan, Chiu, Li & Chu, 1973) n. comb.; Nephrostomum dollfusi (Agarwal, 1959) n. comb.; and Artyfechinostomum neotoma (Jain, 1953) n. comb. Species attributed to Paryphostomum which are here considered species inquirendae are: Paryphostomum (Lepustomum) mehrii Jain, 1953 sp. inq.; P. fragosum (Dietz, 1909) sp. inq.; P. horai Baugh, 1950 sp. inq.; P. huaccaci Ibáñez, 1974 sp. inq.; P. agrawali Gupta & Singh, 1986 sp. inq.; P. siddiqui Gupta & Singh, 1986 sp. inq.; P. durgensis Sapre, 1969 sp. inq.; and P. globorchum Oshmarin, 1970 sp. inq.