No abstract

Our study revealed that all tested populations tolerate wide ranges of salinity, however, different patterns arose among species from different regions. Ponto-Caspian taxa showed lower mortality in fresh water, while Northern European taxa showed lower mortality in fully marine conditions. Genetic analyses showed evolutionary divergence among species from different regions. Due to the geological history of the two regions, as well as high tolerance of Ponto-Caspian species to fresh water, whereas Northern European species are more tolerant of fully marine conditions, we suggest that species originating from the Ponto-Caspian and Northern European regions may be adapted to freshwater and marine environments, respectively. Consequently, the perception that Ponto-Caspian species are more successful colonizers might be biased by the fact that areas with highest introduction frequency of NIS (i.e., shipping ports) are environmentally variable habitats which often include freshwater conditions that cannot be tolerated by euryhaline taxa of marine origin. K E Y W O R D Sfreshwater origin, Gammaroidea, marine origin, nonindigenous species, Ponto-Caspian species, salinity tolerance --

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequences.

We investigated the relationships of the muricid subfamilies Haustrinae, Pagodulinae and the genus Poirieria using a molecular phylogenetic approach on a dataset of three mitochondrial genes (12S, 16S and COI). These taxa form a well-supported clade within Muricidae. The phylogenetic analysis suggests that Poirieria is the sister group of Pagodulinae and that Axymene, Comptella, Pagodula, Paratrophon, Trophonella, Trophonopsis, Xymene, Xymenella, Xymenopsis and Zeatrophon are all worthy of genus-level rank within this subfamily. We propose the use of Enixotrophon for a group of species currently classified in Pagodula. The results also support a new taxonomic arrangement in Haustrinae. radula, accessory salivary gland, oesophagus, paraspermatozoa (in males) and bursa copulatrix (in females). Tan (2003) assigned species of Lepsiella Iredale, 1912, Lepsithais Finlay, 1928 and Haustrum Perry, 1811 to Haustrinae and treated Bedeva Iredale, 1924 as a subgenus of Lepsiella, a classification accepted by Barco et al. (2010). Lepsiella and Lepsithais are now considered to be synonyms of Haustrum (Beu , 2004) and the subfamily currently includes two genera and up to 10 species (depending on the author), geographically restricted to New Zealand and southern Australia, with the sole exception of Bedeva paivae (Crosse, 1864), which has been introduced by human agency to South Africa (Kilburn & Rippey, 1982), the Canary Islands and Madeira (Houart & Abreu, 1994). Barco et al. (2012) analysed the phylogenetic relationships of Southern Ocean muricids traditionally assigned to Trophoninae and investigated differences in radular and penial morphology of 12 genera. Evidence was found for a new subfamily, Pagodulinae, comprising seven genera, four of which were based on molecular data: