The First Record of Eurytemora velox (Lilljeborg, 1853) (Crustacea, Calanoida) outside of Europe, Genetic Identification with Surprise

Abstract

The euryhaline species Eurytemora velox (Lilljeborg, 1853) is an active invader like some other Eurytemora species. Having Ponto Caspian origin, it has been actively spread in fresh and brackish waters throughout Europe during recent decades. At present, the species is found even in Western Siberia. No one record of this species outside of Europe and Western Siberia was done. This paper presents finding of mitochondrial haplotype E. velox in North American waters by molecular-genetic methods with morphological identification. This specimen has nITS genes of north Atlantic American E. cf. affinis and mixed E. velox–E. cf. affinis 18S rRNA gene. We suppose it is result of interspecies hybridization between European E. velox and North American E. cf. affinis. Possibly E. velox was invaded North America with the ballast water of ships from Western Siberia. What is surprising, hybrid of the same two species was observed in the Ural, whereas E. cf. affinis was never found outside of the North American Atlantic coast.