A New Species of Ichthyouris Inglis, 1968 (Nematoda: Pharyngodonidae) Parasitizing Two Characiform Fishes from Tocantins River, Maranhão State, Brazil

Abstract

A new oxyuroid nematode, Ichthyouris nunani n. sp., is described from the intestine of the freshwater benthopelagic characiform fishes Laemolyta taeniata and Curimata acutirostris, both of which were caught in the Tocantins River, State of Maranhão, Brazil. The new species is easily distinguished from all other species of the genus mainly because of the distribution of the male caudal papillae, the morphology of the spicule, and the fact that the eggs have an operculum and many long, thread-like filaments at each pole. This is the first helminth species described in both hosts, and this report contributes to the knowledge of the helminthological fauna of fish in the Neotropical region.

Two new species of Curvianchoratus (Monogenoidea, Dactylogyridae) parasitizing Psectrogaster amazonica (Characiformes, Curimatidae) and a new record for Curvianchoratus singularis in the Tocantins River, Maranhão, Brazil

“…Studies on the parasite diversity of freshwater fish from the Tocantins-Araguaia Basin have gradually increased in recent years [see Fehlauer and Boeger (2005) ; Boeger et al (2006) ; Kritsky et al (2007) ; Domingues and Marques (2011) ; Kritsky et al (2013) ; Aguiar et al (2017) ; Cárdenas et al (2019 , 2021 , 2022 ); Cohen et al (2020) ; Freitas et al (2021) ].…”