CURRENT STUDIES IN HERPETOLOGY

With the help of artificial inter-population crosses of adult Rana temporaria from four spatially remote populations of the European part of the species' range, the magnitude and direction of changes in metamorphic traits were estimated. The maximum values of the size of metamorphs at the end of metamorphosis and the rate of larval growth were found in the descendants of the parents of Belarusian populations (Turov and Minsk) and, as a rule, in hybrid offspring with the participation of the parents of these populations, when crossing with individuals from the population of the Moscow region (ZBS). Outbreeding depression of the time of larval development before the end of metamorphosis and growth rate was revealed when crossing ZBS females with Turov males. In a population from a region with a relatively low climatic temperature (Kirov), the minimum size of metamorphs was revealed, but not the time of larval development. In most crosses, a relatively greater contribution of nonadditive genetic variability, as well as the maternal effect associated with the difference in egg sizes, to the formation of inter-population differences was revealed. The inter-population variability of studied traits related to fitness is often directed along the gradient of environmental conditions, and not counter-gradient (as should be expected based on the conception of counter-gradient selection), which is explained by the choice of different growth and development strategies in tadpoles formed in southern and northern populations.

Predictive maps of the distribution of the marsh frog (Pelophylax ridibundus) in Russia under the conditions of global climate change up to 2100 are presented. It is shown that under the influence of global climate change, the range will expand and the centroid will shift to the north-east. The patterns of the formation of the invasive part of the species range are summarized and maps are created for different models and scenarios of climate change, which include suitable territories for the further dispersal of the species in the European part of Russia, the Urals, Siberia and the Far East. It is shown that with warming in the case of low-sensitivity models, the area of territories suitable for the species will increase by 193(±76)%, and the shift of the center of the range in latitude will be 427(±82) km.

Skink lizards have an unusual complex osteoderm, which consists of several bone elements – osteodermitis. We have carried out the first histological and computer microtomographic study of the structure of the original and regenerating complex osteoderms of skink lizards using Eurylepis taeniolata as an object. The topography of osteoderms in the integument of the original region of the tail and its regenerated part was studied. The fundamental similarity of the morphology and microstructure of the original and regenerated osteoderms was showed. A description of the development of the microstructure of a complex osteoderm in the process of regeneration is given. The presence of osteodermin on the surface of osteoderms in the studied species was revealed.

A critical analysis of literature data on the records of Elaphe sauromates in the Atyrau region of the Republic of Kazakhstan in 1857–2006 is presented. Doubtful finds of the species in the Volga-Ural interfluve and in the vicinity of the city of Atyrau require confirmation. New finds in the region in 2018 and 2021, like all reliable previous ones, were made only on the territory of the Zhylyoysky district.

The paper presents the results of studying the age structure and growth of the eastern tree frog (Hyla orientalis) in the Samur Forest. In the Primorskiy village (Magaramkent district, Republic of Dagestan, Russian Federation) in the first decade of May 2022, 7 females and 13 males were captured. The age of animals was determined by the cross sections of phalanx by standard method of skeletochronology. Age of females was 2–5 years (3.4 on average), males 1–6 years (3.4 on average). Life expectancy (ESP) in females is 4.33 years (S = 0.74), and in males 4.08 years (S = 0.72). The calculated maximum body length in females was 44.25 mm, males 41.54 mm. The growth rate of females is higher (k = 1.33) than that of males (k = 0.89). 

The distribution of smooth snake in the Caspian lowland of Russia and Kazakhstan is analyzed according to the collections of the Zoological Museum of Moscow State University and published works. The map with smooth snake finds includes 36 localities of the species (Volgograd Region, Stavropol Territory, Kalmykia, Chechen Republic, Dagestan, and Kazakhstan).

The sandy massif Sarykum, whose age is about 100 thousand years, is an island habitat for psammophilic species of terrestrial vertebrates. The paper presents new morphometric data on the populations of two species of psammophilous lizards living in this area. These are the nominative subspecies of the Secret Toadheaded Agama (Phrynocephalus mystaceus mystaceus Pallas, 1776) and the Caucasian Central Asian Racerunner (Eremias velox caucasica Lantz, 1928). Body length of sexually mature males of the Secret Toadheaded Agama averages 76.5±3.7 mm (n = 30), and adult females – 68.9±4.2 mm (n = 29). Comparison of the obtained materials with similar parameters of the Kazakhstan population of the subspecies shows that mature individuals of the Sarykum population are significantly smaller: for males td = 1.33 ≥ tst with a confidence level α = 0.80, and for females td = 2.07 ≥ tst with α = 0.95. It is known from the literature that all the pre-Caucasian populations of this species are isolated. Perhaps the small size of mature individuals in them also serve as an example of the manifestation of Foster's rule. The data of the presented study indicate a similar feature of the Sarykum population of the Caucasian Central Asian Racerunner. The body length of mature males at Sarykum is 63.6±2.9 mm (n = 9), and that of females is 58.4±3.0 mm (n = 17). The calculation of the reliability of differences by the Student coefficient shows that the length of the trunk of males (td = 2) and females (td = 0.61) of the Sarykum population does not statistically differ from the averaged materials for the region. At the same time, mature individuals of the Sarykum population are significantly smaller than the nominative subspecies from Kazakhstan: for males td = 1.40 ≥ tst with a confidence probability α = 0.80, and for females td = 2.20 ≥ tst with α = 0.95. It is obvious that Foster's rule does not manifest itself in the subspecies population living on the Sarykum sandy massif, and the conspicuous small size of mature individuals is determined by comparison with the size of the nominative subspecies. An interesting fact is that immature foot-and-mouth of both species do not differ in size from individuals of the same age of other populations. Probably, at this stage of ontogenesis, the overall physiologically optimal size for the species is preserved.

The paper presents data on temperatures of the body and the selected substrate for the steppe-runner and the spotted toadhead agama. Thermal preferences and modal classes for both species were determined, and interspecies differences were analyzed. Significantly higher average temperatures were found in the steppe-runner, while the maximum voluntary temperatures are higher in the spotted toadhead agama. These features are associated with the biotopic confinement of species. Representatives of both species, even in the spring, have a lower body temperature compared to the environment, which is achieved due to behavioral thermoregulation.

This paper is dedicated to the history of the life path and scientific biography of Vladimir Georgievich Ishchenko, the founder of the national amphibian population ecology. He was born in 1938 and formed as a biologist in Leningrad, where he took his first steps in science under the guidance of Pavel Viktorovich Terentyev. In 1961, after graduating from the university, he moved to work in Sverdlovsk, at the Institute of Biology of the Ural Branch of the USSR Academy of Sciences, where he rose from a laboratory assistant to a leading researcher, Doctor of Biological Sciences and worked until his retirement on November 30, 2018. It was in Sverdlovsk (Yekaterinburg from 1723 to 1924 and after 1991) Vladimir Georgievich for a long period (39 years of regular continuous monitoring), conducted research to study the dynamics of the number and age structure of the amphibian population (pointed frog) in the Urals. The area of scientific interests of Vladimir Georgievich covered population ecology, genetic diversity, phylogeny and taxonomy of animals, the state of populations and the protection of the animal world. His work has made a significant contribution to understanding the ecological mechanisms of ontogeny regulation in animals.