Samples issued from intensive sampling in the Netherlands (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) and from extensive sampling carried out in the context of international campaigns (1998, 2000 and 2001) were revisited. Additional samples from artificial substrates (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) and other techniques (various periods) were analysed. The combined data provide a global and dynamic view on the Peracarida community of the River Meuse, with the focus on the Amphipoda. Among the recent exotic species found, Crangonyx pseudogracilis is regressing, Dikerogammarus haemobaphes is restricted to the Condroz course of the river, Gammarus tigrinus is restricted to the lowlands and seems to regress, Jaera istri is restricted to the 'tidal' Meuse, Chelicorophium curvispinum is still migrating upstream into the Lorraine course without any strong impact on the other amphipod species. After a rapid expansion Dikerogammarus villosus has continued its upstream invasion between 1998 and 2002 at a rate of 30-40 km per year, but no further progression was noticed in 2003. Locally and temporarily the native species (Gammarus fossarum and G. pulex) and naturalized species (G. roeseli and Echinogammarus berilloni) may have been excluded by the most recent invaders (mainly D. villosus), but none of the native and naturalized species has disappeared completely. Therefore, the number of amphipod species found in the River Meuse has increased. Moreover, the native and naturalized species keep on dominating the tributaries from which the recent invaders seem to be excluded. A changing Peracarida community structure is observed along the course of the River Meuse: four native or naturalized species inhabit the upstream (Lorraine) course, three invasive species dominate in the middle reach (Ardenne-Condroz zone), one exotic species is housed in the Border Meuse and three or four invasive species dominate the assemblages in the lowlands.

The systematics and phylogeny of the genus Fulvius Stål remains unclear. We present herein the first analysis of the phylogenetic relationships within the genus Fulvius based on DNA sequences. The phylogenetic interrelationships in the genus Fulvius are investigated using partial DNA sequence data from two mitochondrial genes, the 16S ribosomal large subunit and the cytochrome oxidase I (COI). DNA sequences for Fulvius species representing three different subgroups distinguished previously on the base of morphological characters alone are compared to sequences from the closely related genera Rhinocylapidius and Cylapus. The data are analyzed using parsimony and Bayesian inference. The results confirm that on the basis of molecular data we can distinguish the same congruent groups of Fulvius species as using morphological characters, however with inclusion of the specimens of the genus Rhinocylapidius in the bifenestratus-group. Additional studies are needed to clarify the phylogenetic relationships within the tribe Fulviini, as well as within the genus Fulvius and its relation to Rhinocylapidius. However, the results of this study suggest that 16S and COI sequences will be very useful as molecular markers for such studies among these species-groups.

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Three new genera, Pinalitopsis, Nepiolygus, and Apolygopsis, are proposed to accommodate the following new species of Japanese mirine plant bugs: P. rhodopotnia from the Kii Peninsula and Shikoku, and N. arare and A. furvocarinatus from the Ryukyu Islands. A new species of the genus Pachylygus Yasunaga, 1994, P. anthrax, is also described from Shikoku.

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