Prosthenhystera gattii n. sp. (Digenea: Callodistomidae), a gallbladder parasite of Bryconamericus ikaa from the lower Iguazú River, described based on combined molecular and morphological evidence

MARTIN MIGUEL MONTES; JORGE BARNECHE; YASMIN CROCI; SERGIO RODRIGUEZ GIL; STEVE S. CURRAN; WALTER FERRARI; JORGE R. CASCIOTTA; SERGIO R. MARTORELLI

Journal of Helminthology

Cambridge University PressJournals_subscriptions@cup.cam.ac.uk

Año: 2020 vol. 94 p. 1 - 7

Adult forms of members of the Callodistomidae always parasitize the gallbladder of freshwaterfishes and occur in Africa and America. This study provides a description of a new SouthAmerican species belonging in Prosthenhystera from the gallbladder of a characid fish(Bryconamericus ikaa), and ribosomal gene sequences (28S rDNA and ITS1-5.8S-ITS2) areused to demonstrate molecular differences between the new species and congeners as wellas explore interrelationships among congeners. Additionally, the first cytological analysis isconducted for a member of the family to determine chromosome number and arrangement.Prosthenhystera gattii n. sp. most closely resembles Prosthenhystera caballeroi in morphology,but the vitellarium is more extensive reaching anterior to the caecal bifurcation in the newspecies and the uterus is confined to the hindbody in P. gattii n. sp., whereas it extends tothe level of the pharynx in P. caballeroi. Also, the testes, cirrus sac, seminal receptacle andthe ratio of body length to width are larger in P. gattii n. sp. Independent Bayesian inferenceanalyses of 28S rDNA and ITS1-5.8S-ITS2 sequence fragments produced phylograms thatshowed P. gattii n. sp. is more similar to Prosthenhystera obesa + Prosthenhystera oonasticathan P. caballeroi + two unidentified species of Prosthenhystera, but with poor posterior probability support for the node in the ITS1-5.8S-ITS2-based phylogram. Further, the genetic distance between P. oonastica and P. gattii n. sp. are the largest among Prosthenhystera spp.Cytological analysis revealed ten metacentric chromosomes, which is fewer than the 12?18chromosomes present in species from the closely related Gorgoderidae