Abstract The morphological and morphometric variability of the nematode Oswaldocruzia filiformis from ten amphibian species ( Pelophylax ridibundus, lessonae, esculentus, Rana arvalis, temporaria, Bufo bufo, Bufotes viridis, Pelobates vespertinus, Bombina bombina Lissotriton vulgaris ) was studied. sampling performed during period 2018–2020 in fifteen localities European Russia. We examined fol...