Аннотация:The calanoid copepod genus Eurytemora to date contains 24-25 taxa at species level, and represents a challenging group of forms for constructing an accurate description of their phylogeny, explaining their Holarctic distribution, interpreting their possible Tethyan origin, and disclosing their ecology, with such a perfect adaptation to variable salinity values.During the last decades Eurytemora, in particular the former group of cryptic species provisionally denoted as E. affinis sensu lato, became a popular model group for molecular genetic investigations, especially in studies on the human mediated distribution of invasive aquatic organisms.An international conference was held in St. Petersburg, Russia, 13-17 May 2019, of which this volume includes some of the papers.A wide spectrum of studies on Eurytemora and several other related calanoids was presented by scientists from 16 countries, mainly from Europe, but also from Canada, Kazakhstan, Taiwan, China, Bangladesh, Puerto Rico and the U.S.A.In this issue, most of the papers deal with Eurytemora studies and were organized in the conference programme in four sessions: Phylogeny (chairs: Carol Eunmi Lee and Victor R. Alekseev); Biogeography (chairs: Jiang-Shiou Hwang and Elena Kochanova); Taxonomy (chairs: Natalia Sukhikh and Łukasz Sługocki); and Ecol-
