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Molecular and morphological screening of Podocotyle spp. (Trematoda: Opecoelidae) sheds light on their diversity in Northwest Pacific and eastern European Arctic

Published online by Cambridge University Press:  19 October 2023

S. Sokolov
A.N. Severtsov Institute of Ecology and Evolution, RAS, 119071, Moscow, Russia
S. Shchenkov
Department of Invertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
E. Frolov
Sakhalin Branch of Russian Federal Research Institute of Fisheries and Oceanography, 693023 Yuzhno-Sakhalinsk, Russia
S. Denisova
Department of Invertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
I. Gordeev*
Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia Department of Invertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
Corresponding author: Ilya Gordeev; Email:


Podocotyle is a genus of marine opecoelid digeneans that parasitize a wide variety of fish as adults. We present the first phylogenetic analysis of several Podocotyle isolates using nuclear 28S rDNA and mitochondrial cox1 DNA regions. New sequences were obtained for Podocotyle specimens from fish caught in the Sea of Okhotsk and the White Sea. Based on morphological and molecular data, eight Podocotyle lineages of species rank were revealed. However, this diversity is poorly formalized within the current taxonomic model of the genus. As a result, we identified Podocotyle cf. angulata, Podocotyle cf. atomon, Podocotyle cf. reflexa, Podocotyle atomon of Sokolov et al., 2019, Podocotyle sp. of Denisova et al., 2023, Podocotyle sp. 1, Podocotyle sp. 2 and Podocotyle sp. 3. We also highlight the unresolved question of the life cycles of representatives of Podocotyle whose intramolluscan stages parasitize the intertidal snails Littorina spp.

Research Paper
© The Author(s), 2023. Published by Cambridge University Press

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