Three new species of Urocleidoides (Monogenoidea: Dactylogyridae) parasitizing characiforms (Actinopterygii: Characiformes) in Tocantins River, states of Tocantins and Maranhão, and new record for U. triangulus in Guandu River, state of Rio de Janeiro, Brazil

Abstract

Three new species of Urocleidoides Mizelle & Price, 1964 are described from the gills of characiform fishes in the Tocantins River and its tributaries. Urocleidoides boulengerellae sp. nov. is described from Boulengerella cuvieri (Spix & Agassiz, 1829) and differs from all its congeners by the dorsal bar with a long posteromedial projection; male copulatory organ with 2–3 counterclockwise rings and a base with a flange; an accessory piece comprising a robust Y-shaped unit and a sheath-like unit; and a highly sclerotized vaginal canal. Urocleidoides paratriangulus sp. nov., described from Psectrogaster amazonica Eigenmann & Eigenmann, 1889, Cyphocharax gouldingi Vari, 1992, Caenotropus labyrinthicus (Kner, 1858) and Mylesinus paucisquamatus Jégu & Santos, 1988, is most similar to Urocleidoides triangulus (Suriano, 1981) Rossin & Timi, 2016 based on the shape of the anchors and bars but differs from U. triangulus in the morphology of the projection of the dorsal bar, the number of rings of male copulatory organ, and by the smaller size of members of hook pairs 1 and 5 compared with those of the remaining pairs. Urocleidoides tocantinensis sp. nov. is easily distinguished from all other species of the genus by the morphology of the vagina, which present a vaginal vestibule with a membranous cap. Urocleidoides triangulus is reported from its type host in the Guandu River, state of Rio de Janeiro. The present study increases the number of Urocleidoides species to 37 recognized species that fit all the generic characters.

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) ].…”

“…The finding of three species of the genus in P. amazonica confirms the high specificity of the genus to neotropical curimatid hosts. On the other side, Psectrogaster amazonica harbors five monogenoidean species, two from a generalist monogenoidean genus, Urocleidoides (parasites from three different fish orders) ( Freitas et al 2021 ) and three from the specialist genus Curvianchoratus .…”

“…Several studies have demonstrated parasitism by monogenoids in Curimatidae fish in the Neotropics (Table 1 ). However, research involving the helminth fauna of P. amazonica is still incipient, with only two monogenoids described for this host so far ( Freitas et al 2021 ). Other studies regarding this fish species refer to larval development, the distribution of larvae in a natural breeding area, hematological parameters, and branchial histopathological alterations ( Nascimento and Araújo-Lima 1993 ; Carvalho et al 2009 ; Ponte et al 2017 ; Bezerra et al 2020 ; Pereira et al 2020 ).…”

A new species of Urocleidoides Mizelle & Price, 1964 from the gills of Schizodon nasutus Kner, 1858 (Characiformes, Anostomidae) in southeastern Brazil

“…Urocleidoides Mizelle & Price, 1964 is one of the most species-rich among the Neotropical dactylogyrid genera, comprising 52 valid species (Kritsky et al 1986;Zago et al 2020;Santos-Neto and Domingues 2023), and currently includes species parasitising the gills and nasal cavities of fishes of the orders Characiformes, Gymnotiformes, Cyprinodontiformes, and Siluriformes (although this last one still requires revision) (Ferreira et al 2018;Oliveira et al 2020;Zago et al 2020;Freitas et al 2021;Oliveira et al 2021;Santos Neto and Domingues 2023). The genus was proposed by Mizelle and Price (1964) to accommodate Urocleidoides reticulatus Mizelle & Price, 1964 (type-species) from Poecilia reticulata (=Lebistes reticulatus) Peters, 1859 (Cyprinodontiformes, Poeciliidae) from an aquarium in Sacramento California, USA (probably collected from the Amazon river basin), which was characterised by the presence of a sinistral vagina and copulatory complex comprising an accessory piece and a non-articulated male copulatory organ.…”

Integrative taxonomy ofUrocleidoidesspp. (Monogenoidea: Dactylogyridae) parasites of characiform and gymnotiform fishes from the coastal drainages of the Eastern Amazon, Brazil

“…Among the Neotropical dactylogyrids, members of Urocleidoides Mizelle & Price, 1964 stand out for their wide distribution in host groups, with species parasitizing the gills and nasal cavities of fishes of the orders Characiformes, Gymnotiformes, Cyprinodontiformes, and Siluriformes (Oliveira et al 2020; Zago et al 2020; Freitas et al 2021; Oliveira et al 2021). The genus Urocleidoides was proposed by Mizelle & Price (1964) to accommodate U. reticulatus Mizelle & Price, 1964, collected from the gills of Poecilia reticulata Peters (Cyprinodontiformes, Poeciliidae) of the Capital Aquarium, Sacramento, California, USA.…”