Rhinoxenus (Dactylogyridae) parasitizing piranhas (Serrasalmidae) at its southernmost limit of distribution (Paraná River, Argentina), with the description of two new species

Autor: MARÍA A. ROSSIN, PABLO N. DE FRANCESCO, MANUEL M. IRIGOITIA, PABLO A. SCARABOTTI, VERÓNICA TAGLIORETTI, JUAN T. TIMI
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Anais da Academia Brasileira de Ciências, Vol 91, Iss 4 (2019)
Druh dokumentu: article
ISSN: 1678-2690
0001-3765
DOI: 10.1590/0001-3765201920190711
Popis: Abstract Abstract: Three piranha species, Serrasalmus maculatus, S. marginatus and Pygocentrus nattereri, living sympatrically in the lower Paraná River (Argentina) were examined searching for nasal monogeneans to know its diversity and distribution. Four species of monogeneans belonging to Rhinoxenus were found parasitizing the nasal cavities. Two new species are described, and new morphological data of 2 previously described species is provided. Rhinoxenus argentinensis n. sp. is characterized by having the male copulatory organ (MCO) as a coiled tube with a reel shaped-base; an elongated accessory piece articulated to base of MCO; a sinistral vagina with a sclerotized vestibule, and a sclerotized cap of the ventral anchor laterally modified forming a triangular expansion. Rhinoxenus paranaensis n. sp. is characterized by having a MCO as a coiled tube with a reel-shaped base; an accessory piece with an elongate proximal portion, a dilated distal portion with digitiform projections articulated to base of MCO; a sinistral vagina with 5-6 cuticular spine-shaped processes, and a sclerotized cap of the ventral anchor modified laterally forming a bilobate expansion. Additionally, multivariate discriminant analyses showed significant morphometric differences in the ventral anchors among Rhinoxenus species parasitizing ‘piranhas ’.
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