Composition and Content of Fatty Acids in Muscle Tissue of the Potanin Altai Osman Oreoleuciscus potanini (Cypriniformes, Actinopterigii) from Mongolian Reservoirs.

The composition of fatty acids in the muscle tissue of the unique Central Asian carp-like fish, Potanin Altai osman Oreoleuciscus potanini, was studied for the first time. The populations of these fish in the reservoirs of the semiarid zone (Durgun and Taishir) during the period of their formation are considered. It was shown that the content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in O. potanini corresponds to the median of this value in the order Cypriniformes. It was established that the basis of the food web of the herbivorous form of this species consists of microalgae (diatoms, Euglena and, possibly, chrysophytes), as well as bacteria. At the same time, the levels of bacterial biomarkers, 15-17BCFA and 17:0 were significantly higher in fish in the Durgun reservoir, whereas the level of EPA (diatom biomarker) in O. potanini was higher in the Taishir reservoir. The established higher values of the heavy nitrogen isotope content in the muscles of O. potanini from the Taishir reservoir are most likely associated with the yet unformed benthic communities and with the incomplete diversification of the riverine form of the Potanin Altai osman into lacustrine forms.

The Role of the Grass Snake Natrix natrix (Reptilia, Colubridae) in the Transfer of Polyunsaturated Fatty Acids from Aquatic to Terrestrial Ecosystems to Land.

As a result of analyses of fatty acid (FA) composition in the grass snake Natrix natrix and its food objects, tadpoles and metamorphs of two amphibian species: the moor frog Rana arvalis and the Pallas spadefoot toad Pelobates vespertinus, it was shown for the first time that the high total content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in the biomass of the snakes indicates its important role in the transfer of these essential substances from aquatic ecosystems to land. It was found that, since food sources of DHA in terrestrial ecosystems are absent, its high level in R. arvalis metamorps and grass snakes may be provided only by synthesis from biochemical precursors contained in food of aquatic origin.

Rapid Morphological Diversification of the Cyprinid Fish Oreoleuciscus potanini (Cyprinidae) in the Course of Formation of a Reservoir in a River of the Semiarid Zone.

The analysis of phenetic diversity in Potanin Altai osman Oreoleuciscuspotanini from the Taishir Reservoir built in 2007 on the Zavkhan River (Great Lakes Hollow, Mongolia), revealed four morphologically discernible forms. Earlier, there were described two forms of O. potanini from the riverine part of the Zavkhan River and three forms in the lakes of the Great Lakes Hollow. The data of the study demonstrate similarity with cyclic morphogenesis in the closely related species Oreoleuciscushumilis in the Lakes Valley also belonging to the Central Asian closed basin.

The first case of morphological differentiation of Altai Osman Oreoleuciscus potanini (Cyprinidae, Actinopterigii) in a river.

The variability of osteological characters has been investigated in cyprinid fish of the genus Oreoleuciscus (Potanin Altai osman) from the river Zavkhan; this fish species is endemic for water bodies of Central Asia. Multivariate analysis of 13 quantitative parameters of the size of the cerebral and visceral skull and the pectoral girdle and the construction of ontogenetic channels allowed the detection of morphologically distinct forms in the fluvial habitats. The result obtained provides additional proof of the possibility of sympatric diversification of fish in river ecosystems. One of the two fluvial forms discovered has been shown to be identical (with regard to the osteological characters) to a previously described herbivorous form of O. potanini from the standing water bodies of the Great Lakes Hollow (Western Mongolia).

Analysis of fatty acid composition revealed differences in the diets of tadpoles of two amphibian species.

The study of the composition of fatty acid markers of tadpoles of cohabiting amphibian species for the first time revealed differences in their diets: the moor frog Rana arvalis prefers bacteria not associated with plant detritus, whereas the diet of the common spadefoot Pelobates fuscus is based on cyanobacteria, green algae, diatoms, and possibly higher plants. Major differences in the fatty acid composition are determined by the difference in the percentage of eicosapentaenoic and myristic acids.