title: Two new species of Parspina Pearse, 1920 (Digenea: Cryptogonimidae) from freshwater fishes (Gymnotiformes) of the Paraná River basin in Argentina.
abstract: Two new species of the cryptogonimid genus Parspina Pearse, 1920 are described from gymnotiform fishes of the Paraná River basin, P. carapo n. sp. from the banded knifefish Gymnotus carapo Linnaeus and P. virescens n. sp. from the glass knifefish Eigenmannia virescens (Valenciennes). Parspina carapo differs from P. virescens in the number of oral spines (32-39 vs 30-33) and their length (28-47 vs 16-28 μm), the distribution of tegumental spines and their anchorage, the types of sensory papillae on the body surface (three vs two types), the extent of body length posterior to the caeca (5 vs 13% of the total body length), the dimensions of the pars prostatica (52 × 34 vs 24 × 10 μm), and in the absence of a gonotyl (vs presence). Both P. carapo and P. virescens differ from P. bagre Pearse, 1920 and P. argentinensis (Szidat, 1954) in the number of oral spines (20-21 and 21-28 in the latter pair) and their length (28-32 and 35-60 μm), and in total body length. Additionally, the two new species differ from P. argentinensis in the arrangement of the vitelline follicles (one continuous band vs two groups on each side of the body) and in having a smaller pars prostatica (149 × 49 μm in the latter). Parspina carapo is the fifth intestinal helminth found in G. carapo, and P. virescens is the first found in E. virescens.
authors.affiliation: Laboratorio de Helmintología, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Int. Güiraldes 2160, Pabellón II, 4º Piso, C1428EGA Buenos Aires, Argentina. ostrowskimargarita@gmail.com
authors.forename: Margarita C Ostrowski
authors.initials: MC
authors.lastname: de Núñez
authors.forename: Nathalia J
authors.initials: NJ
authors.lastname: Arredondo
authors.forename: Alicia A Gil
authors.initials: AA
authors.lastname: de Pertierra
mesh_terms: D000818:Animals; D001118:Argentina; D005260:Female; D005618:Fresh Water; D023702:Gymnotiformes / Q000469:parasitology*; D007422:Intestines / Q000469:parasitology; D008297:Male; D008855:Microscopy, Electron, Scanning; D010053:Ovary / Q000033:anatomy & histology; D045483:Rivers; D013737:Testis / Q000033:anatomy & histology; D014200:Trematoda / Q000033:anatomy & histology / Q000145:classification* / Q000302:isolation & purification / Q000648:ultrastructure