Diversity of the Piscicola Species (Hirudinea, Piscicolidae) in the Eastern Palaearctic with a Description of Three New Species and Notes on Their Biogeography

Biodiversity is considered one of the most significant parameters for characterizing aquatic environments. The value species diversity taken into account when assessing ecological state and quality ecosystem. However, erroneous taxonomic identification distorts biodiversity signification and, consequently, prevents a clear understanding signals traits. In this study, we presented first data on Piscicola leech in vast area Eastern Palaearctic. To avoid misidentifications, an integrated approach was applied, combining modern DNA-based classical morphological methods. Previously, only genus, geometra, recorded whole Siberia. We discovered three new species: sibirica sp. nov., khubsugulensis nov. (Eastern Siberia) nordica (European Northeast). pojmanskae reduced to synonymy with whose description updated. Taxonomic adjustments allowed us ascertain eastern edge geometra distribution understand biogeography group as whole. range limited Western Siberia, while widespread purely Khovsgolian inhabit