A new species of Cacatuocotyle (Monogenea, Dactylogyridae) parasitizing two species of Astyanax (Ostariophysi, Characidae) in southern Brazil

Abstract

A new species of Cacatuocotyle is described from the external surface of Astyanax aff. fasciatus and Astyanax jacuhiensis from Lake Guaíba, State of Rio Grande do Sul, Brazil. It differs from the other three species of the genus, recorded from Mexico and the State of Paraná, Brazil, by possessing an accessory piece with a long proximal portion, a U-shaped bar with irregular posterior margin in its midportion, and a haptor containing two circular thickenings with muscular anterior margins. Only one monogenean species, Urocleidoides astyanacis (= Characithecium costaricensis) was recorded for the host Astyanax aff. fasciatus, whereas none were known for A. jacuhiensis. This paper records a new host (A. jacuhiensis) for monogeneans in southern Brazil and extends southward with the geographical distribution of the genus Cacatuocotyle to the State of Rio Grande do Sul, Brazil.