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  • Author: O. M. Kovalchuk x
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Abstract

A new species of pikeperch from the Upper Miocene strata of Ukraine (Egorovka 2 locality, MN 12) is described in the paper. Extinct species Sander svetovidovi sp. n. differs from the Miocene and recent taxa of the genus Sander by the configuration of the quadrate bone, form and sizes of the lateral condyle and also presence of additional double crista on the anterior inferior edge of quadratum.

Abstract

A new fossil species Perca neopleistocenica Kovalchuk, sp. n. from Southern Ukraine is described. It differs from other species of the genus by width and configuration of praeoperculum, and also by quantity of cogs on the posterior edge of os praeoperculare

Abstract

The present paper deals with results of the study of porgy fish (Sparidae) remains from the upper Miocene, lower and upper Pliocene, and the lower Pleistocene of Ukraine. Isolated molariform teeth were assigned to Pagrus cinctus, Pagrus sp., as well as to Sparidae? gen. et sp. indet. These findings expand our knowledge of the species composition of the Late Cenozoic fish assemblages of Southeastern Europe and force partially reconsider conclusions formulated earlier about their environment.

Abstract

This paper presents analytical results of the study of adaptatiogenesis within the family Arvicolidae (Mammalia, Rodentia) based of morphological changes of the most functional characters of their masticatory apparatus — dental system — through time. The main directions of the morphological differentiation in parallel evolution of the arvicolid tooth type within the Cricetidae and Arvicolidae during late Miocene and Pliocene were identified and substantiated. It is shown that such unique morphological structure as the arvicolid tooth type has provided a relatively high rate of evolution of voles and a wide range of their adaptive radiation, as well as has determined their taxonomic and ecological diversity. The optimality of the current state of this group and evaluation of evolutionary prospects of Arvicolidae were presented and substantiated here as a phenomenon in their evolution.

Abstract

The skull fragment of muskox Ovibos moschatus (Artiodactyla, Bovidae) obtained from Chasha River bed alluvium near the Buryn (Sumy Region, North-Eastern Ukraine) is described here in detail. It belongs to a young male, and presumably dates back to Late Pleistocene. This new find slightly extends the known Ukrainian range of the species to the east. Taxonomic attribution of extinct muskox and dispersal of Ovibos moschatus within the territory of Ukraine during the Late Pleistocene are also discussed in the paper.

Abstract

For the first time, an analysis of structural damage of the peripheral blood erythrocyte nucleus in Rutilus rutilus (Linnaeus, 1758) was carried out for the rivers of the north-western region of Ukraine. The effect of the hydrochemical regime on the formation of cytogenetic disturbances of the representatives of this species was also clarified. It was observed that during 2013–2017, the content of phosphates, suspended solids, fluorides, iron, copper, zinc, manganese, nitrite nitrogen and nitrate nitrogen in the surface waters of rivers most significantly exceeded the current quality standards. The average frequency of nuclear disorders of peripheral blood erythrocytes R. rutilus from the studied hydrosystems is 5.25 ± 0.29 ‰ (p < 0.01), with a noticeable excess of the level of spontaneous mutations in the older age groups of fish. In all analyzed samples of R. rutilus, among the total number of identified structural disorders of the nucleus, the largest share is made up of red blood cells from the micronucleus (from 40.0 to 62.0 %), which is evidence of cytogenetic disturbances in the body of fish. At the same time, disturbances of erythrocyte blood of roach from small rivers are on average 1.3 times (or 21.9 %) higher compared with individuals from medium-sized rivers. The formation of cytogenetic disturbances in R. rutilus under the conditions of the hydrochemical regime of rivers is described by a close (r = 0.99 at p < 0.003) multifactorial regression dependence. More important regressive coefficients of the dependency are acquired by such biogenes (NH4+, NO3−, PO4−) and toxicants (Cu2+, Zu2+, Mn2+, F2) in the background of oxygen regime peculiarities (COD, BOD5, O2).

Abstract

The use of the biological method is promising for treating underground waters from iron compounds. Iron bacteria used in the process are widely spread in weak acidic and neutral underground waters containing iron ions (II), dissolved carbon dioxide and minimum concentrations of oxygen. The relevant direction of present-day biotechnology is the use of iron bacteria for treating underground waters. The goal of this research is to compare the efficiency of using the biological method for treating underground iron containing weak acidic and neutral waters under different conditions. As the test-objects, Gallionella and Lepthotrix iron bacteria were used. The sedimentation of bio-minerals was obtained from the washout waters of the biological deironing station. Calcium soda was used as an additional source of inorganic carbon for bacteria. As a result of the studies it is established that the use of the non-reagent method gives the possibility to achieve only 80% efficiency in removing iron compounds while the use of sodium carbonate results in increasing efficiency up to 93%. To determine the contribution of biological purification of ground water from iron compounds, the bacteria were inhibited with the preparation of polyhexamethylene guanidine (PHMG) chloride. It was found that inhibition of Gallionella and Lepthotrix led to the reduction of 50% of the iron removal effect. The mechanism was developed of inhibiting the process of iron bacteria metabolism by PHMG (polyhexamethylene guanidine). The new technology of arranging a block-module station for treating underground waters is proposed.