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The edible frog, Pelophylax esculentus, is a hybrid form that reproduces via clonal propagation of only one of the parental genomes through generations of hybrids while the genome of other parental species is eliminated during gametogenesis. Such reproductive ability requires hybrids to coexist with one of the parental species or rarely both parental species causing the formation of so-called population systems. Population systems and reproductive biology of water frogs from the east of the range remained partially unexplored. In this study, we investigated the distributions, population systems, genetic structure, types of gametes, and morphological variability of water frogs of the genus Pelophylax from the northeastern parts of their ranges (Mari El Republic and adjacent territories, Russia). We examined 1,337 individuals from 68 localities using morphological traits combined with DNA flow cytometry and a multilocus approach (fragments of a nuclear and two mitochondrial genes). We revealed five types of population systems: “pure” populations of the parental P. ridibundus (R) and P. lessonae (L), mixed populations of parental species (R-L) along and with their hybrids (R-E-L), as well as mixed populations of P. lessonae and P. esculentus (L-E). However, the “pure” hybrid (E) and the mixed P. ridibundus and P. esculentus (R-E) population systems were not found. All hybrids studied by DNA flow cytometry were diploid. Analysis of gametogenesis showed that the majority of hybrid males, as well as hybrid females from the L-E system, produced gametes with the P. ridibundus genome. However, in the R-E-L system, hybrid females were usually sterile. The reproduction of hybrids in such systems is primarily based on crosses of P. esculentus males with P. lessonae females. Molecular analysis showed the presence of mitochondrial and nuclear DNA

Knowledge about the distribution of living organisms on Earth is very important for many areas of biological science and understanding of the surrounding world. However, much of the existing distributional data are scattered throughout a multitude of sources, such as taxonomic publications, checklists and natural history collections and often, bringing them together is difficult. A very successful attempt to solve this problem is the GBIF project, which allows a huge number of researchers to publish data in one place in a single standard. Our dataset represents a significant addition to the occurrences of amphibians in the Volga, Don riverine basins and adjacent territories. The dataset contains up-to-date information on amphibian occurrences in the Volga river basin and adjacent territories, located for the most part on the Russian plain of European Russia. The dataset is based on our own studies that were conducted in the years 1996-2020. The dataset consists of 5,030 incident records, all linked to geographical coordinates. A total of 13 amphibian species belonging to nine genera and six families have been registered within the studied territory, although the distribution of amphibian species in this region of Russia has not yet been fully studied. This is especially relevant with the spread of cryptic species that can only be identified using molecular genetic research methods. The main purpose of publishing a database is to make our data available in the global biodiversity system to a wide range of users. The data can be used by researchers, as well as helping the authorities to manage their territory more efficiently. All occurrences are published in GBIF for the first time. Most of the data are stored in field diaries and we would like to make it available to everyone by adding it in the global biodiversity database (GBIF).

The analysis of ways for development of anecological framework of the Kazan city agglomeration is given in the paper. Currently, about1.7 million people live in this territory. The Kazan urban agglomeration has amonocentric structure and includes the city of Kazan, its satellite towns, as well as 6 municipal districts. Sustainable development of this territory requires mandatory consideration of the environmental component. The most important role in the ecological component belongs to the ecological frame work of agglomeration. Currently, the basis for the formation of the ecological frame work of the Kazan urban agglomeration is existing natural ecosystems: water objects, and forested areas. The work defines nuclei that are considered fundamental points of the natural ecological framework. It is the Volga-Kamsky state natural biosphere reserve in Laishev sky and Zelenodol sky districts, the State nature reserve of regional significance" Sviyazhsky" in Verkhneuslonsky district; the monument of nature of regional importance "Semiozer sky forest" in Vysokogor sky district; the State Nature Reserve of Regional Importance of the Landscape Profile " The Old Mill " in the Pestrechinsky District, and the Lenino-Kokushkin sky State Nature Reserve of Regional Importance and the Integrated Profile. Keywords: urbanization, ecological framework, Kazan urban agglomeration

O papel dos animais no ecossistema é determinado por uma ampla gama de fatores. Este é, antes de tudo, o número, a biomassa e a natureza da alimentação. Devido ao fato de que a taxa metabólica em diferentes grupos de animais não é a mesma, o indicador mais importante de sua importância no funcionamento do ecossistema é o fluxo de energia que passa pela comunidade (energia transformável). O artigo apresenta dados sobre o uso de energia transformável para avaliar os recursos de espécies terrestres de vertebrados nas condições da fazenda de caça "Sviyazhskoe. A abordagem implementada pode ser aplicada a diferentes territórios. Uma limitação fundamental pode ser apenas a ausência de dados sistemáticos sobre os registros de todos os grupos.

The article presents the first results of a study of age and growth of the Hyrcanian frog, Rana pseudodalmatina in the Talysh Mountains. The animals were caught in the first Decade of March 2011 in Sym village in Astara District of Azerbaijan. The age was determined by a skeletochronological analysis of clipped phalanges of the third toe of hind limb. Preparations were made and examined with well-visible thick sections of 56 males and 7 females. Males in the sample were 1 – 5 years old and females were 2 – 4 years old. The average age of males was 3.2 years and 3.7 years of females. Most of studied frogs were specimens in the age of three and four years. The most intensive growth of the Hyrcanian frog occurs before reaching sexual maturity. A male at the age of one year had a body length equal to 309.8% of the average length of the metamorphs from the same reservoir, two-year-old males were 328.8 – 341.3%, three-year-olds were 271.7 – 385.9%, four-year-olds were 347.8 – 388.6%, five-year — 369.6 – 421.2%. The relative length of a two-year-old female was 342.4%, three-year-old females — 391.3 – 432.1, four-year-olds — 383.2 – 397.8%.