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The poorly known taxon Gammarus orientalis (S. Karaman, 1934), described and known from Derbend in Erdschias-dag Mts (=Erciyas-dagi), on 2100 m about sea level (Asia Minor) is described and figured based on holotype and paratypes. As the known taxonomic characters of this taxon were scarce and incomplete, this taxon was considered the synonym of Gammarus balcanicus Schäferna, 1922. The established morphological characters and geographical distribution of orientalis support distinct status of this taxon.

[The results presented in this paper point to the need for a revision of the known distribution areas of the species Gammarus balcanicus and Gammarus fossarum, as well as of their contact zones, both on the territory of Serbia and on the Balkan peninsula as a whole.The occurrence of G. fossarum in western Serbia contradicts the assertion that G. balcanicus is the best represented species of this genus in western Serbia and indicates a considerably wider range for G. fossarum.The results presented herein undermine the previously held belief that G. fossarum is only sporadically encountered in Serbia (especially in southern and southeastern Serbia) and indicate that it is the most abundant and most frequently found species in the catchment area of the Southern Morava (southeast Serbia). Moreover, mixed populations of these two amphipods are encountered at the majority of the localities in the Southern Morava.It is here established that the zone of contact between G. balcanicus and G. fossarum is considerably wider than was imagined and in reality stretches into southern and southeastern Serbia: it was previously thought that the contact zone lies between the rivers Morava and Drina in western Serbia and on Mt. Kopaonik in central Serbia. Since G. fossarum is dominant in relation to G. balcanicus in the given region, it can be expected that future finds will further extend the zone of contact between these two vicariant forms to the south and southeast of the Balkan Peninsula. Les resultats presentes dans ce travail indiquent la necessite de reviser les aires de repartition connues des especes Gammarus balcanicus et Gammarus fossarum, ainsi que leurs zones de contact, a la fois sur le territoire de Serbie et sur la peninsule des Balkans dans son ensemble.La presence de G. fossarum en Serbie occidentale contredit l'assertion suivant laquelle G. balcanicus est l'espece de ce genre la plus representee en Serbie occidentale et indique une aire considerablement plus vaste pour G. fossarum.Les resultats presentes ici remettent en cause la croyance suivant laquelle G. fossar um se rencontrait seulement sporadiquement en Serbie (en particulier dans le sud et le sud-est de la Serbie) et indiquent que c'est l'espece la plus abondante et la plus frequemment trouvee dans les eaux de Moravie meridionale (Serbie sud-orientale). De plus, des populations mixtes de ces deux amphipodes sont presentes dans la majorite des localites de la Moravie meridionale.Il est etabli ici que la zone de contact entre G. balcanicus et G. fossarum est considerablement plus large qu'on ne l'imaginait et en realite, elle s'etend jusqu'en Serbie du sud et du sud-est: on pensait auparavant que la zone de contact se situait entre les rivieres Morava et Drina en Serbie occidentale et sur le mont Kopaonik en Serbie centrale. Etant donne que G. fossarum est dominant par rapport a G. balcanicus dans cette region, on peut s'attendre a ce que des trouvailles futures etendent la zone de contact entre ces deux formes vicariantes vers le sud et le sud-est de la peninsule des Balkans., The results presented in this paper point to the need for a revision of the known distribution areas of the species Gammarus balcanicus and Gammarus fossarum, as well as of their contact zones, both on the territory of Serbia and on the Balkan peninsula as a whole.The occurrence of G. fossarum in western Serbia contradicts the assertion that G. balcanicus is the best represented species of this genus in western Serbia and indicates a considerably wider range for G. fossarum.The results presented herein undermine the previously held belief that G. fossarum is only sporadically encountered in Serbia (especially in southern and southeastern Serbia) and indicate that it is the most abundant and most frequently found species in the catchment area of the Southern Morava (southeast Serbia). Moreover, mixed populations of these two amphipods are encountered at the majority of the localities in the Southern Morava.It is here established that the zone of contact between G. balcanicus and G. fossarum is considerably wider than was imagined and in reality stretches into southern and southeastern Serbia: it was previously thought that the contact zone lies between the rivers Morava and Drina in western Serbia and on Mt. Kopaonik in central Serbia. Since G. fossarum is dominant in relation to G. balcanicus in the given region, it can be expected that future finds will further extend the zone of contact between these two vicariant forms to the south and southeast of the Balkan Peninsula. Les resultats presentes dans ce travail indiquent la necessite de reviser les aires de repartition connues des especes Gammarus balcanicus et Gammarus fossarum, ainsi que leurs zones de contact, a la fois sur le territoire de Serbie et sur la peninsule des Balkans dans son ensemble.La presence de G. fossarum en Serbie occidentale contredit l'assertion suivant laquelle G. balcanicus est l'espece de ce genre la plus representee en Serbie occidentale et indique une aire considerablement plus vaste pour G. fossarum.Les resultats presentes ici remettent en cause la croyance suivant laquelle G. fossar um se rencontrait seulement sporadiquement en Serbie (en particulier dans le sud et le sud-est de la Serbie) et indiquent que c'est l'espece la plus abondante et la plus frequemment trouvee dans les eaux de Moravie meridionale (Serbie sud-orientale). De plus, des populations mixtes de ces deux amphipodes sont presentes dans la majorite des localites de la Moravie meridionale.Il est etabli ici que la zone de contact entre G. balcanicus et G. fossarum est considerablement plus large qu'on ne l'imaginait et en realite, elle s'etend jusqu'en Serbie du sud et du sud-est: on pensait auparavant que la zone de contact se situait entre les rivieres Morava et Drina en Serbie occidentale et sur le mont Kopaonik en Serbie centrale. Etant donne que G. fossarum est dominant par rapport a G. balcanicus dans cette region, on peut s'attendre a ce que des trouvailles futures etendent la zone de contact entre ces deux formes vicariantes vers le sud et le sud-est de la peninsule des Balkans.]

According to the classical point of view, the genus Gammarus had originated in inland waters and subsequently some of its representatives colonized marine habitats. Very recent studies point out reverse scenario with the Tethys Ocean and Paleocene as a spatiotemporal frame for the origin of the genus, followed by divergence of main Gammarus species groups later in Tertiary. Diversity, and phylogeny, within these lineages has been scarcely studied so far. Yet, already it is known that that the conventionally recognized morphospecies hide substantial cryptic diversity. That is especially true in Southern European glacial refugia were high genetic diversity of many animal species in these areas is commonly attributed to effect of Pleistocene glaciations. Our study aimed to reveal cryptic diversity and phylogeography of G. balcanicus, species widely distributed in Europe. We used one nuclear (28S rRNA) and two mitochondrial (COI, 16S rRNA) markers sequenced for ca. 1000 individuals from 112 sampling sites in South-Eastern Europe, ranging from Alps to Crimean Peninsula and from northern Carpathians to southern Balkan Peninsula. In result, the morphospecies appeared to be complexes of dozens of highly divergent lineages, some dating back to the lower Neogene. Taking into account spatial distribution of these lineages and paleogeography of the area, the view that main Gammarus lineages diverged in freshwaters seems much simplified. Within G. balcanicus, several independent colonizations of inland waters in various areas of its present range can be assumed and related to emergence of once isolated land masses from the regressing Paratethys. Shallower phylogenetic divisions can be attributed to the Alpide orogeny, repetitively reshaping hydrography of the area. This study was supported by the Polish Ministry of Science and Higher Education (projects no. N N303 579439 and 5818/B/P01/2010/39) and partially by the internal funds of the University of Lodz

In a small isolated lake in Slovakia, the fish acanthocephalan Pomphorhynchus laevis using Gammarus balcanicus and the minnow Phoxinus phoxinus, respectively, as its intermediate and final hosts, represented a dominant helminth species. Its prevalence and intensity of infection in fish showed no significant variation during a year fluctuating above the mean values of 89 % and 6.6 worms per fish. The mean prevalence of P. laevis larvae in Gammarus was 41.4 % with a maximum in the late summer and autumn ; individual crustaceans were infected by 1-9 larvae. There was one generation of P. laevis per year. Following up an annual cycle, an occurrence of new infections of Gammarus culminated in October and in the next May for Phoxinus. The sex ratios of both the adults and larvae of acanthocephalans were near unity but favoured slightly males in spring and autumn. The distribution of P. laevis in minnows and crustaceans was highly aggregated and fitted with the negative binomial model. The spatial distribution analysis of parasites along the fish alimentary tract showed a clear preference of P. laevis for its proximal half, with the maximum numbers in the site of the first intestinal loop. Immature worms of both sexes predominated in the proximal region and moved slightly down the alimentary tract during their growth and maturation.

The response to some heavy metals (Cd, Cu, and Zn) was examined in two amphipods, Niphargus montellianus and Gammarus balcanicus, living in karst waters and endowed with different ecological characteristics. Exposure experiments were made, in the controlled conditions of a biospeleology laboratory, to increasing concentrations of metals in the range 0.1-10 μg ml -1 for up to 10 days. Hypogean and epigean amphipods differed in their responses, G. balcanicus being more sensitive to the toxic effects of heavy metals than the hypogean N. montellionus. The degree of tolerance was Cu

Life history pattern of the amphipod Gammarus balcanicus occurring in the Western Bieszczady Mountains is given and compared with literature data concerning the biology of this species.

The amphipods are major food items for many commercial fishes, and they are used as protein food for agricultural animals. In the present paper are presented the results of four-year observations on the feeding of Gammarus balcanicus in nature and in an aquarium. Among the studied aspects were the dependence of daily food ration on sex and physiological state (with and without eggs) and feeding on different kinds of plant food. The study concludes that Gammarus balcanicus willingly feed on soft half-decayed plant residues; into their ration also enters food of animal origin. In contrast to other amphipods, G. balcanicus eats representatives of its own species very rarely, and only dead or immobile ones. Translated from Russian into English