Oswaldocruzia filiformis sensu lato (Nematoda: Molineidae) from amphibians and reptiles in European Russia: morphological and molecular data

Abstract

Nematodes of the genus Oswaldocruzia parasitise the small intestine of amphibians and reptiles. Their biodiversity remains unknown. We studied Oswaldocruzia nematodes from nine species of amphibians and reptiles (Pelophylax ridibundus, Rana arvalis, Rana temporaria, Bufo bufo, Lacerta agilis, Zootoca vivipara, Anguis fragilis, Natrix natrix, Vipera berus) at six localities in European Russia in 2018-2019. To identify their nematode species, we analysed the morphological characters traditionally used in the taxonomy of nematodes of this genus together with new molecular phylogenetic data. The results of partial sequencing and molecular phylogenetic analysis of CoxI mtDNA gene showed that all Oswaldocruzia specimens in this study belonged to the same species. We observed a broad morphological variability of nematodes both from different host species and from the same host individual. Morphological variation in nematodes from various host species could be host-induced, while that in nematodes from the same host individuals could be due to phenotypic plasticity of the species. Molecular data indicate that only one species of the genus Oswaldocruzia, O. filiformis s.l., which has a broad morphological variability, parasitises amphibians and reptiles in European Russia. The results of our study highlight the necessity of studying the diversity of morphologically similar Oswaldocruzia spp. from the Western Palearctic by molecular genetic methods.

Helminth communities in amphibians from Latvia, with an emphasis on their connection to host ecology

“…Waterbody size did affect helminth abundances but not their species richness in our study. The nematode O. filiformis is also common in sand lizards (Lacerta agilis) from dry terrestrial habitats (Kirillova et al, 2020). It infects hosts through ingestion of its larvae with terrestrial food (Chikhlyaev et al, 2019b) and its higher infection rates in frogs from smaller waterbodies could be caused by higher proportions of terrestrial prey items in such habitats (relevant studies on waterbody-size-specificity of their diets are absent).…”

An Overview of the Helminths of Moor Frog Rana arvalis Nilsson, 1842 (Amphibia: Anura) in the Volga Basin

“…Distribution: Palaearctic. The results of partial sequencing and molecular phylogenetic analysis of CoxI mtDNA gene showed that all Oswaldocruzia species in this study belonged to the same species [119].…”

Oswaldocruzia franciscoensis n. sp. (Nematoda: Molineidae) in Leptodactylus macrosternum Miranda-Ribeiro, 1926 (Anura: Leptodactylidae) from Caatinga morphoclimatic domain, Brazil: morphological and molecular characterisation

“…Furthermore, phylogenetic approaches to representatives of Molineidae are limited since they include few species or are focused only on certain genera (De Bellocq et al 2001;Chilton et al 2006;Kirillova et al 2023). In relation to Oswaldocruzia, the situation may be considered more critical because only five out of 90 species have been genetically characterised, namely, O. belenensis Santos, Giese, Maldonado & Lanfredi, 2008, O. chabaudi Ben Slimane & Durette-Desset, 1996, O. chambrieri Ben Slimane & Durette-Desset, 1993, and O. filiformis and O. ukrainae Ivanitzky, 1940, in addition to several sequences labelled as Oswaldocruzia sp., in which makers for cox1 are by far the most common (see Willkens et al 2016;Kirillova et al 2020Kirillova et al , 2023. Therefore, the currently limited genetic evidence does not allow further conclusions about the phylogeny of Oswaldocruzia.…”

“…2016; Kirillova et al . 2020, 2023). Therefore, the currently limited genetic evidence does not allow further conclusions about the phylogeny of Oswaldocruzia.…”