Morphology and molecular phylogeny ofBychowsky & Nagibina, 1969 (Monogenoidea) parasitizing marine catfish (Ariidae) from the Atlantic coast of South America: a new species, supplementary taxonomic information and new insights.

Abstract

In this study, a new dactylogyrid species is described from the gills of two ariid fish species of the Brazilian coast,and, by combining morphological characters with partialsequences. The new species can be distinguished from its congeners by the following morphological characteristics: a male copulatory organ (MCO), a coiled tubular shaft of around one counterclockwise ring, base with a sclerotized cap; MCO with tapered distal region; a T-shaped accessory piece; a vagina, a cup-shaped vaginal vestibule, slightly sclerotized; and a pharynx comprising a muscular, glandular bulb. Supplementary taxonomic data forfrom(type-host) are also presented and newsequences ofspp. from other ariid fish from South America are provided. Phylogenetic analyses based on partialgene sequences placedn. sp. andas two early divergent lineages withinfrom South America. Finally, a way to test the monophyly ofandis also discussed, which may be useful for future studies.