Deep in the systematics of Camallanidae (Nematoda): using integrative taxonomy to better understand the phylogeny and consistency of diagnostic traits

New species of Serpinema (Nematoda: Camallanidae) from the scorpion mud turtle Kinosternon scorpioides (Testudines: Kinosternidae) from eastern Amazon, Brazil

The genus Serpinema Yeh, 1960 allocates parasitic nematodes of freshwater turtles distributed across the Oriental, Neotropical, and Palearctic regions. Five of 10 valid species of the genus Serpinema occur in the Neotropical region, and three have been recorded parasitizing Kinosternon scorpioides Linnaeus, 1766. In the present work, we describe a new species of Serpinema, a gastrointestinal parasite of K. scorpioides from the Brazilian Amazon, using light and scanning electron microscopy. Serpinema pelliculatus n. sp. differs from other species of the genus by the number and distribution of caudal papillae and spicule morphology. The new species is the seventh recorded for the Neotropical region.

Review of the metazoan parasites of the economically and ecologically important African sharptooth catfish Clarias gariepinus in Africa: Current status and novel records

One of the most widely distributed African freshwater fish is the African sharptooth catfish Clarias gariepinus (Burchell) that is naturally distributed in 8 of the 10 ichthyofaunal regions of this continent. Clarias gariepinus is a highly valued and cheap staple to local communities and an ideal aquaculture species. Consequently, interest in the parasitic communities of C. gariepinus has increased as parasites may accidentally be ingested by humans when eating uncooked fish or can be introduced into culture systems through fish stocks supplied from local rivers which affect yield, growth, and marketability. This review provides an overview of the ∼107 metazoan parasite species known to parasitise C. gariepinus in Africa and their general life cycles, morphology, paratenic and post-cyclic infections, and the biogeography and validity of records are discussed. A brief overview is included on the application of some of these parasites in environmental studies and their link to human health.

Cucullanus pinnai pinnai and C. pinnai pterodorasi (Nematoda Cucullanidae): what does the integrative taxonomy tell us about these species and subspecies classification?

Cucullanus pinnai has been divided in two subspecies (C. pinnai pinnai and C. pinnai pterodorasi) based on the morphology of oesophastome. While C. pinnai pinnai apparently shows low host specificity and broad geographic occurrence, with certain morphological variations, C. pinnai pterodorasi was reported once, parasitizing Pterodoras granulosus. We used an integrative taxonomic approach to evaluate whether or not populations of C. pinnai pinnai from Trychomycterus spegazzinii (Escoipe River, Argentina) and Pimelodus fur (Miranda River, Brazil), and of C. pinnai pterodorasi from Pterodoras granulosus (Miranda River, Brazil) are conspecific. Parasites were observed using light microscopy and genetically characterized based on partial sequences of the 18S and 28S rDNA, ITS1-5.8S-ITS2, and COI mtDNA. Phylogenies were reconstructed and the Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (bPTP), and Automatic Barcode Gap Discovery (ABGD) were used for species delimitation purposes. The present samples formed well-supported monophyletic assemblages, corroborating in part the results of morphological analyses; however, they grouped according to geographic origin. Species delimitation suggested conspecificity of C. pinnai pinnai with C. pinnai pterodorasi from Brazil; consequently, the morphology of oesophastome may be an intraspecific variation. Results also indicated that C. pinnai may represent a species complex as samples from Argentina were suggestive of an independent specific entity. However, definitive affirmations are premature, since there is no autapomorphy for separating C. pinnai from Brazil and Argentina and sampling was limited to three host species from two river basins. The phylogenetic reconstructions also confirmed the artificiality of some genera within Cucullanidae.

Review of the parasitic nematodes of marine fishes from off the American continent

The ichthyofauna of the Atlantic and Pacific coasts off the American continent is very rich. Consequently, a high biodiversity of nematodes parasitizing these vertebrates is also expected. Currently, data on nematode parasites of marine fish off the Americas are fragmented. A review of all adult nematode species reported parasitizing marine fish from off the American continent is herein presented, as well as comments on their patterns of diversity, life cycles and advances in the taxonomic and phylogenetic knowledge. A total of 209 valid species, 19 species inquirendae and 6 dubious records have been recorded, the majority from the fish taxa Eupercaria and Perciformes. The families Sciaenidae, Serranidae and Lutjanidae, as well as the tropical and temperate Atlantic waters, exhibited the highest records of parasitic nematodes. The Cucullanidae, Philometridae and Cystidicolidae were the most speciose families of nematodes, which may be related to technological advances and relatively recent efforts of taxonomists, resulting in description of new taxa and the resolution of taxonomic problems. Numerous taxonomic questions still need resolution and, even though genetic data have been important for this process, the database is very scarce. This is the first review on all currently known nematode species parasitizing marine fish off the Americas and may serve as an important basis of reference for future approaches on these organisms.

Checklist of nematodes parasitizing fish in the Brazilian Amazon

This study presents a list of parasitic fish nematodes from the Brazilian Amazon based on the previous Brazilian list including scientific assessments carried out between 2010 and 2021. A total of 16 families, 48 species and 28 undetermined species of nematodes associated with fish are included in the checklist, in addition to 93 host species and 15 geographical records.