Basic characteristics of zooperiphyton in large rivers of Western Siberia (Tyumen oblast)

The data on the qualitative and quantitative composition of zooperiphyton from seven large rivers of Western Siberia are presented. The species similarity of zooperiphyton has been documented in most of the rivers. The biomass in unpolluted parts is mainly formed by the larvae of caddis flies. Factors which effect the composition and structure of zooperiphyton have been determined. Changes in the structure and quantitative development of zooperiphyton are shown.     

Distribution and community structure of Ostracoda (Crustacea) in shallow waterbodies of southern Kenya

The current study presents the ostracod communities recovered from 26 shallow waterbodies in southern Kenya, combined with an ecological assessment of habitat characteristics. A total of 37 waterbodies were sampled in 2001 and 2003, ranging from small ephemeral pools to large permanent lakes along broad gradients in altitude (700–2 800 m) and salinity (37–67 200 µS cm^?1). Between 0 and 12 species were recorded per site. Lack of ostracods was associated with either hypersaline waters, or the presence of fish in fresh waters. Three of the 32 recovered ostracod taxa, Physocypria sp., Sarscypridopsis cf. elizabethae and Oncocypris mulleri, combined a wide distribution with frequent local dominance. Canonical correspondence analysis on species–environment relationships indicated that littoral vegetation, altitude, surface water temperature and pH best explain the variation in ostracod communities. Presence of fish and water depth also influence species occurrence, with the larger species being more common in shallow waterbodies lacking fish. Based on Chao’s estimator of total regional species richness, this survey recovered about two-thirds (60–68%) of the regional ostracod species pool. Scanning electron micrographs (SEM) of the valve morphology of 14 ostracod taxa are provided, in order to facilitate their application in biodiversity and water-quality assessments and in palaeoenvironmental reconstruction.     

Taxonomic and trophic structures of dominants in the zooperiphyton of waterbodies and watercourses of the upper Volga basin

All the main trophic groups of invertebrates are presented in the compositions of dominant assemblages of zooperiphyton in the studied waterbodies and watercourses. The strong pollution of water by suspended solids of anthropogenic origin in the water of the upper Volga reservoirs leads to the suppression of typically sessile filter-feeding invertebrates (sponges, bryozoans, and Dreissena) able to form the highest biomass of zooperiphyton using natural food items. The conditions of the disturbed structure of food resources are favorable for the development of detritivores-gatherers. In small rivers receiving industrial wastewaters, excessive amounts of food in the water column and in the form of sediments on the substrates suppresses invertebrates-biofowlers and facilitates the expansion of the benthic larvae of chironomids of g. Chironomus (combining the filtration and gathering of food particles on the substrates) to the vacant spatial niches. At the same time, the role of nematodes and oligochaetes with prevailing detritophages increases. In the acidified lakes of the Darwinsky National Reserve, the decrease in the total species diversity of zooperiphyton is accompanied by decreases in the role of filter-feeding invertebrates. The chironomid larvae and oligochaetes prevailed in the poor zoocenoses. The roles of predatory caddisfly larvae, black gnats, and nematodes increased. The labile structural characteristics of zooperiphyton with the conservation of the historically formed methods of foraging are the main modern way that biofouling communities adapt to changes in the quality and quantity of food resources upon modern anthropogenic pollution of the aquatic environment.     

The fauna of bivalves of the superfamily Pisidioidea in the small waterbodies and watercourses of Northwestern Russia (Vologda oblast)

This study of freshwater bivalves of the superfamily Pisidioidea was carried out in small waterbodies and watercourses of the central part of Vologda oblast in 2000–2005. It revealed 24 species from 13 genera and 3 families. The investigated bodies of water were grouped according to the similarity of the mollusk species composition. An analysis of the distribution of ecological and biogeographical groups of Pisidioidea was also made.     

Ostracods (Ostracoda,Crustacea) from two freshwater lakes near Maarssen,The Netherlands

Summary In Lake Maarsseveen I (with the lowest trophic level) 15 ostracod species were collected, whereas 9 species were found in Lake Maarsseveen II.Physocypria kliei Schäfer, 1934, andCypridopsis obesa Brady and Robertson, 1869, are new to the Dutch fauna.     

New Cnidaria species in Saratov oblast waterbodies (Povolzhye)

Cnidaria species that were earlier unknown in the waterbodies of Saratov oblast have been found in this region in the last decade. Colonies of Cordylophora caspia (Pallas, 1771) were found on stems of Phragmites australis (Cav.) Trin. ex Steud. in the basin cooler of the Balakovo nuclear power plant (Saratov water reservoir), while the freshwater jellyfish Craspedacusta sowerbii Lankaster, 1880 was found in the Saratovka River (Volgograd water reservoir). It is possible that these species penetrate into waterbodies with foreign plants or are introduced by birds. Another possibility is that their discovery is due to a more thorough examination of the waterbodies’ biota.     

Chironomids fauna (Diptera, Chironomidae) in some waterbodies and watercourses of Mongolia

An annotated list of chironomid species from some waterbodies and watercourses of Mongolia identified by an imaginal developmental stage is presented. The list includes 97 species of 39 genera and 5 subfamilies: Tanypodinae (6 species), Diamesinae (1), Prodiamesinae (2), Orthocladiinae (33), and Chironominae (55). Of all found chironomid imagos, 11 species have been earlier identified for the Mongolian fauna, the other 86 species have been registered for the first time. The largest number of species has been recorded in Lake Sangiyn-Dalai—28; in Lake Ugiy and River Ider—19 species. In the rest of the lakes, the number of recorded species varies from 18 to 10 species, and in rivers, from 13 to 2. Most of the species are boreal and widespread. The number of Paleoarctic species amounts to 44 and Holarctic species amounts to 49.     

Spatial structure of zooperiphyton in a small river (West Siberia)

Basic quantitative characteristics of zooperiphyton from the Uk River are presented. Factors effecting the composition and structure of invertebrates have been found. The effect that the current velocity, water level, and different types of pollution have on zooperiphyton in the small river is shown. The pollution of the river reduces taxonomic diversity. The maximum effect is caused by the discharge of mineralized waters. In clean portions of the river, Trichoptera dominate in biomass; in polluted parts, their role decreases and the larvae of chironomids and leeches prevail in zooperiphyton.     

Belica Leucaspius delineatus (Cyprinidae) in waterbodies of southwest Siberia

We analyze Distribution and habitats of the belica (Leucaspius delineatus), a species accidentally introduced to waterbodies of southwest Siberia. The northern limits of the range of this species in the region are determined. Data are given on the sex ratios, size and age structure, growth, feeding, fecundity, and time and conditions of spawning of the belica in waterbodies of different types. It is shown that males of the earlier age groups are prevalent in belica populations.     

The First Find of Vestalenula danielopoli (Martens,Rossetti et Fuhrmann, 1997) (Crustacea,Ostracoda, Darwinulidae) in Holocene deposits of Western Siberia

Finds of the European fossil species Vestalenula danielopoli in the Holocene peat deposits of Western Siberia are reported. The age of the deposits is 8850 cal yr BP. The species first appeared at the beginning of the Atlantic period (5750 cal yr BP), and disappeared at the beginning of the Subatlantic period (2200 cal yr BP). Vestalenula danielopoli co-occurred with species typical for temporary shallow bodies of water.     

Non-marine Ostracoda (Crustacea) of Banat district in Serbia

In order to enrich the knowledge on ostracods in Serbia, field work was carried out in the central and southern part of the Banat district during 2002 and 2003. Samples from the collection of the Institute of Zoology, Faculty of Biology in Belgrade were also examined. Altogether, 133 samples were investigated. In this research, 23 ostracod species were found. Most of them have a Palaearctic distribution. Ilyocypris decipiens, Bradleycypris obliqua and Tanycypris pellucida are new to the faunas of Serbia and Montenegro, as is the subfamily Cypricercinae. Three species were found again after several decades, including a new and stabile population of Candona natronophila Petkovski, 1969 . The most frequent species were Cypridopsis vidua and Physocypria kraepelini. Statistical analysis of ostracod communities and their relations to measured ecological variables is also given.     

Appendage Homologies and the First Record of Eyes in Platycopid Ostracods, with the Description of a New Species of Keijcyoidea (Crustacea: Ostracoda) from Japan

A median nauplius eye is reported for the first time in a platycopid ostracod, a group hitherto considered to be blind. A new species of the platycopid ostracod genus Keijcyoidea is described from coastal rocky marine habitats on the Pacific coast of Japan. Observations of living specimens in the laboratory show that it is capable of burrowing to a depth of several millimeters in sandy sediment, using the first two head appendages (antennulae and antennae) and the furca. Females brooded a maximum of five eggs in the posterior brood space of the carapace. The homologies and phylogenetic implications of the trunk segmentation and limbs are discussed, paying particular attention to the sexually dimorphic fifth and sixth limbs; the copulatory appendages of both sexes are interpreted as being attached to trunk segments T6–T7 (counting from the posterior; T1 = posteriormost segment).     

Global diversity of ostracods (Ostracoda,Crustacea) in freshwater

There are close to 2,000 subjective species and about 200 genera of Recent non-marine Ostracoda. Together, Cyprididae (1,000 spp.) and Candonidae (c. 550 spp.) represent more than 75% of the extant specific diversity; the remaining 11 families comprise the other 25% of the species. The Palaearctic region has the highest absolute non-marine ostracod diversity, followed by the Afrotropical. The Australian region has the highest relative endemicity. About 90% of the species and 60% of the genera occur in one zoogeographical region only. This means that all the biological mechanisms which lead up to efficient dispersal and which are present in at least part of the non-marine Ostracoda (e.g. brooding, drought-resistant eggs, parthenogenesis) have not induced common cosmopolitan distributions in ostracods. Several habitats are hotspots for ostracod diversity and endemicity. For example, it appears that the ancient lakes hold up to 25% of the total ostracod diversity. Other speciation-prone habitats are groundwater, temporary pools and Australian salt lakes; in the latter two instances, cladogenesis has often been paralleled by gigantism. The present ostracod diversity results from 9 to 12 separate invasions of the non-marine habitat, starting about 400 Myr ago. Genetic diversity can be very different in different species, mostly, but not always, related to reproductive mode. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Ultrastructure of the carapace margin in the Ostracoda (Arthropoda: Crustacea)

In podocopid ostracods, the “hingement”, with teeth/sockets or crenulations, is developed along the attached dorsal margin of the carapace. Dual calcified lamellae, called “duplicatures” are also developed along the free margin. However, the terminology of these marginal areas is often confused by many ostracodologists because of their differing interpretations and viewpoints. In this study, the marginal areas of the carapace were observed in detail, using the transmission (TEM) and scanning (SEM) electron microscopes. Consequently, the terminology of the marginal areas has been revised. The homology between attached and free margins and the structural differences of duplicatures, for some taxa are also discussed.     

Salinity tolerance of Mytilocypris henricae (Chapman) (Crustacea,Ostracoda)

Salinity tolerance, and the effects of temperature upon it, of the Australian ostracod Mytilocypris henricae (Chapman) was determined in direct transfer experiments using adults. Animals were subjected to a combination of 11 salinities (ranging between 0.0 g · 1^–1 and 45.0 g · 1^–1) and 4 temperatures (10, 15, 20 and 25 °C). Survival was analysed using two statistical techniques: the logit linear model and the proportional hazards model. Results show that both salinity and temperature have a significant effect on survival, but there is no significant interaction between temperature and salinity.     

The species composition of zooplankton in waterbodies and watercourses of the great lakes depression

The species composition of zooplankton in lakes, reservoirs, and watercourses of the Great Lakes Depression (Mongolia) is examined. Its changes depending on the type of water objects and water mineralization are shown. Under changes in the climate and the economic situation in Mongolia, the species diversity in fresh waterbodies is seen to increase, which is also due to species that are indicators of eutrophication. The minimum changes in the species composition take place in highly mineralized lakes where zooplankton is characterized by the lowest species diversity. The formation of the zooplankton faunistic composition corresponds to changes that were observed earlier in reservoirs of the Volga cascade. The species composition of zooplankton in watercourses varies significantly and depends on the character of the source of a river and its length.