Persistence of phylogeographic footprints helps to understand cryptic diversity detected in two marine amphipods widespread in the Mediterranean basin

Amphipods of the genus Gammarus are a vital component of macrozoobenthic communities in European inland and coastal, marine and brackish waters of the Mediterranean and the Black Sea. Exceptional levels of cryptic diversity have been revealed for several widespread freshwater Gammarus species in Europe. No comprehensive assessment has yet been made for brackishwater counterparts, such as Gammarus aequicauda and G. insensibilis, which are among the most widely dispersed members of the so-called “G. locusta group” in the Mediterranean and in the Black Sea. Here we probe the diversity of these morphospecies examining the partitioning of mtDNA and nDNA across multiple populations along their distribution range and discuss it within the regional paleogeographic framework. We gathered molecular data from a collection of 166 individuals of G. aequicauda and G. insensibilis from 47 locations along their distribution range in the Mediterranean including the Black Sea. They were amplified for both mitochondrial COI and 16S rRNA as well as the nuclear 28S rRNA. All five MOTU delimitation methods (ABGD, BIN, bPTP, GMYC single and multiple threshold models) applied revealed deep divergence between Black Sea and Mediterranean populations in both G. aequicauda and G. insensibilis. There were eight distinct MOTUs delimited for G. aequicauda (6–18% K2P) and 4 MOTUs for G. insensibilis (4–14% K2P). No sympatric MOTUs were detected throughout their distribution range. Multimarker time-calibrated phylogeny indicated that divergence of both G. aequicauda and G. insensibilis species complexes started already in the late Oligocene/early Miocene with the split between clades inhabiting eastern and western part of the Mediterranean occurring in both species at the similar time. Our results indicate a high cryptic diversity within Mediterranean brackishwater Gammarus, similar to that observed for freshwater counterparts. Moreover, the phylogenetic history combined with the current geographic distribution indicate that the evolution of botThis work was supported by Polish National Science Center (projects no. 2014/15/B/NZ8/00266 and 2015/17/N/NZ8/01628) and partially by the statutory funds of the Department of Invertebrate Zoology and Hydrobiology of University of Lodz. F. Costa and the University of Minho contribution was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02