Search Results (2)

The genus Eurytemora is a diverse group of copepods found in coastal, estuarine, brackish, and freshwater environments. The main research has focused on Eurytemora affinis (Poppe, 1880) and revealed it to be a species complex. Eurytemora velox (Liljeborg, 1853) has only recently been characterized in the Scheldt estuary but never within a global phylogenetic context. This study integrated nearly all European Eurytemora species sequences available, along with original ones from the Scheldt. A total of 351 sequences were analyzed using one mitochondrial gene (CO1) and one nuclear gene (nITS), with sequencing performed specifically on the CO1 gene. Phylogenetic reconstructions were performed using the Maximum Likelihood method, along with haplowebs and genetic diversity indices. A significant subdivision between six European species was observed. The monophyletic clade status of the E. affinis complex was confirmed alongside the existence of three geographically isolated lineages of the E. affinis species, the East Atlantic, the North Sea/English Channel, and the Baltic lineages, each exhibiting pronounced genetic differentiation. The population of E. velox from the Urals differs significantly from the European ones. These results provide both an overview of the genetic structure of the genus in geographic Europe as well as new insights on E. velox. Full article

The recent distribution of the Ponto-Caspian calanoid copepod, Eurytemora velox, in Western and Eastern Europe has been well-documented; however, there are no studies on the genetic diversity of the recently discovered Western Siberian species population. To contribute towards filling this gap, genetic diversity and distribution were investigated for E. velox collected in the Urals and Western Siberia of the Russian Federation to compare with the European populations. In this study, 44 specimens were dissected for the morphological studies, and 22 specimens of E. velox from different geographical points were analyzed for mitochondrial cytochrome oxidase I (CO1), nuclear ITS1-ITS2 (nITS) and nuclear ribosomal RNA (18SrRNA) gene fragments. Analysis of the CO1 gene region showed that the studied populations from the Urals and Western Siberia differ significantly from European ones and represent a separate genetic line. However, the nuclear nITS and 18SrRNA genes, as well as the results of morphological analysis, did not show such isolation of the Trans-Ural populations from those in Europe. As in many studies on E. velox, we found atypical structural features of the fifth prosomal leg among females in the Ob Bay. Their share was 36% of the number of studied individuals. The CO1 shows that the divergence of genetic lines occurred approximately in the Middle Pleistocene, and the species itself is Paleogene–Neogene by origin. Based on these data, a different scenario of E. velox distribution or possible refuge survival is discussed. Full article