bluuebunny/crossref_metadata_2025 huggingface dataset:
MODERN RENDS IN THE POPULATIONS OF THE SIBERIAN CRANE (GRUS LEUCOGERANUS) AND THE SANDHILL CRANE (GRUS CANADENSIS) (GRUIDAE, GRUIFORMES) IN THE TUNDRA OF YAKUTIA AND CHUKOTKA, BASED ON AERIAL SURVEYS
Authors: Rozenfeld S. B. , Bysykatova-Harmey I. P. , Barykina D. A. , Kirtaev G. K. , Solovyeva D. V.
Published: April 2024

The Sandhill crane has become a common to abundant breeding species in the tundra of northeastern Yakutia, with the ranges of both Sandhill and Siberian cranes presently overlapping widely. Further range expansion of the Sandhill crane to the west and a population increase can assist competition to the stenotopic Siberian crane which is classified as a Critically Endangered species by the IUCN. To assess the dynamics of the Siberian and Sandhill crane populations, we repeated the historical aerial surveys of 1993–1995 along the Arctic coast of Yakutia and Chukotka in 2020 to 2021. Novel methods of our survey included the use of a photo-camera in addition to a voice recorder and a GPS navigator. The survey data were processed using QantumGIS 3.16.5 software. The overlapping area of both crane species expanded significantly in 2020 to 2021 as compared to 1993–1995. The local densities correlate negatively: in those areas where the density of the Sandhill crane increased, the density of the Siberian crane decreased or the latter one disappeared. The Siberian crane disappeared from the western part of the Kolyma Lowland and the Kolyma Delta, where a peak population density of the Sandhill crane has recently been reported. Our data show some concentration of the Siberian crane range in the Yana-Indigirka Lowland. Areas of the maximum density of the two species do not coincide, the distance between their centers amounting to 400 km. The center of the maximum density of the Sandhill crane has shifted to the west by 400 km from the Chaun Lowland to the Kolyma Delta over 28 years, while the numbers remain almost stable. They increased 1.22 times between the aerial surveys and can be estimated at 41,930 individuals in the areas under survey. The density of the Siberian crane increased 5.3 times over the same years, the population numbering 2.086 individuals in the surveyed areas.
A NEW SPECIES OF THE GENUS THINODROMUS KRAATZ 1857 (COLEOPTERA, STAPHYLINIDAE, OXYTELINAE) FROM MALAYSIA
Authors: Gildenkov M. Yu.
Published: April 2024

Thinodromus (s. str.) excisius sp. n. is described from Pahang state, Malay Peninsula, Malaysia. The new species belongs to the Thinodromus lunatus group which is widespread in Southeast Asia. Based on the structure of the unpaired anterior scutum of the aedeagus sac, within the lunatus group it seems to be especially similar to the following species: Thinodromus (s. str.) cattiensis Gildenkov 2017; Thinodromus (s. str.) spotus Gildenkov 2017; Thinodromus (s. str.) batuensis Gildenkov 2021, and Thinodromus (s. str.) bruneiensis Gildenkov 2021. However, it differs well from them and other species of the lunatus group by the structure of the parameres which show a characteristic notch.
SEASONAL DYNAMICS OF THE DIET OF IMPERIAL EAGLES (AQUILA HELIACA, ACCIPITRIDAE, ACCIPITRIFORMES) IN THE LEFT-BANK MIDDLE VOLGA REGION
Authors: Korepov M. V. , Arbuzova L. A.
Published: April 2024

The seasonal and between-year dynamics in the diet of a pair of Imperial eagles (Aquila heliaca) were observed at a nesting site on the left bank of Volga River in the Ulyanovsk Region, European Russia. The research covered three seasons (2019–2021) using an autonomous video surveillance system. During the research period, 555 prey objects brought by eagles to the nest were identified, these representing 30 taxa of wild vertebrates and four species of domestic animals, all from four vertebrate classes. The predominant prey objects were the Russet ground squirrel (Spermophilus major) (35%), the Rock pigeon (Columba livia) (22%), and the Common hamster (Cricetus cricetus) (14%). Rodents prevailed in nutrition during nest construction (April), hatching (May), and at the initial stages of feeding the chick(s) (June–July). The proportion of pigeons and corvines increased significantly in nutrition during the feeding period of grown-up chicks and fledglings (August–September). Raising two chicks compared to one chick led to an average of 1.5 times increase in food intake, mainly due to rodents.
MORPHOLOGY OF THE DECAPODITE STAGES OF ARGIS LAR (OWEN 1839) (CARIDEA, CRANGONIDAE) FROM THE KRONOTSKY BAY, EASTERN KAMCHATKA
Authors: Sedova N. A.
Published: April 2024

Two decapodite stages of the shrimp, Argis lar, family Crangonidae, from the plankton off the Kronotsky Bay, northwestern Pacific, eastern Kamchatka, are described. Сomparison of The available larvae were morphologically compared with decapodites of other species of this family with a shortened development. The first and second decapodite stages were similar in size and structural features of the pleon, carapace, antennae, mandibles, maxillae, pereiopods, and pleopods. Significant differences were found in the morphology of the telson, maxilliped, and antennules in the first and second decapodite stages of A. lar. In the second decapodite stage, the posterior median spine shifted to the middle of the carapace, the number of antennular and maxilliped endopod segments were increased, the epipodite appeared in the third maxilliped, the shape of the telson changed, the terminal spines in the telson disappeared, and the relative length of the angular setae were decreased. Kuro shrimps are thought to have three to five larval stages.
THE MAIN DIRECTIONS OF MAMMALIAN EVOLUTION
Authors: Agadzhanyan A. K.
Published: April 2024

Modern views on the origin and early evolution of mammals are presented. The work uses the material accumulated by the author on the morphology of modern and fossil monotremes, marsupials and placentals. Data on Mesozoic mammals, including those obtained in recent years, are summarized. A model of the mechanism of morphogenetic transformations during the evolutionary development of Mammalia is proposed. An overview of the main directions of the formation of mammals from the Late Triassic to the Cenozoic is given.
DESTRUCTION OF GUILLEMOT COLONIES IN THE SOUTHERN BARENTS SEA AND THE FACTORS THAT DETERMINE IT
Authors: Krasnov Yu. V. , Ezhov A. V.
Published: April 2024

Features of Common guillemot (Uria aalge) and Brünnich’s guillemot (U. lomvia) numbers dynamics have been analyzed based on long-term monitoring data obtained from colonies from the southern Barents Sea coast. Since the 2000s, the numbers of guillemots in colonies have been shown to gradually decrease. In 2019–2021, most of the guillemot colonies of the southern Barents Sea coast disappeared. Two factors have been found to affect the guillemot colonies’ dynamics in the last decades: fishing industry and change in oceanographic conditions. These two factors indirectly influence the guillemot populations in the winter-spring area, changing the availability of the birds’ food resources. The former affects only the birds from southwestern Barents Sea colonies, but the second is relevant within the whole winter-spring area from the Barents Sea to the western areas of the North Atlantic. They affect the guillemots’ living conditions in the most critical periods of their life. In future this may cause significant changes in the location of guillemot colonies in the southern Barents Sea.
HELMINTH FAUNA OF BLACK-LEGGED KITTIWAKES (RISSA TRIDACTYLA, LARIDAE, CHARADRIIFORMES) IN THE NORTHERN PART OF KARA SEA
Authors: Kuklin V. V. , Kuklina M. M. , Ezhov A. V.
Published: April 2024

The results of original studies on the helminth fauna of the Black-legged kittiwake (Rissa tridactyla L.) (10 ad. and 10 juv.) in the northern part of Kara Sea (Severnaya Zemlya Archipelago and Wiese Island) carried out in 2019–2020 are presented. Eight species of helminthes (1 trematode, 4 cestodes and 3 nematodes) have been registered. For the first time in seabirds in the high latitudes of the Arctic, the trematode, Diplostomum sp. and the nematode, Paracuaria adunca have been recorded. Adult birds have been established to be infected mainly with cestodes of the family Dilepididae while nestlings mainly with cestodes of the family Tetrabothriidae. The presence of 5 common species in the helminth fauna of kittiwakes in the northern part of Kara Sea and in the northern part of Novaya Zemlya (Severnyi Island) has been noted due to the similarity of the feeding range of the birds in these areas. Possible causes for the features revealed in the infection of kittiwakes (food preferences, distribution of the foci of invasion and the influence of abiotic factors) are analyzed.
REDESCRIPTION OF MORARIA (BAIKALOMORARIA) LONGICAUDA BORUTZKY 1952 (COPEPODA, HARPACTICOIDA, CANTHOCAMPTIDAE) FROM LAKE BAIKAL
Authors: Alekseeva T. M. , Sheveleva N. G. , Timoshkin O. A.
Published: April 2024

An illustrated redescription of the female and male of Moraria (Baikalomoraria) longicauda Borutzky 1952 is presented, a harpacticoid species endemic to the littoral zone of Lake Baikal, Siberia. A neotype is designated, because the type material is lost. The morphology of this species was studied in detail using scanning electron microscopy for the first time. An illustrated description of the mouthparts and antennules is given; that of the swimming legs being expanded. The structure of the genital field is shown and data on morphological variability are presented.
ТАКСОНОМИЧЕСКОЕ ИЗУЧЕНИЕ ПАНЦИРНЫХ КЛЕЩЕЙ РОДА GRAPTOPPIA BALOGH 1983 (ACARI, ORIBATIDA, OPPIIDAE)
Authors: Ermilov S. G.
Published: April 2024

Род панцирных клещей Graptoppia (Oribatida, Oppiidae) зарегистрирован впервые на Кубе. Описан один новый вид подрода Graptoppia (Graptoppia) – G. (G.) trapezoides sp. n.; описание базируется на имаго, собранных в листовом опаде прибрежного смешанного леса. Суммированы родовой и подродовые признаки Graptoppia. Предложен идентификационный ключ для определения известных видов Graptoppia (Graptoppia).
REARING RODENT PUPS IN FOSTER FAMILIES OF TNEIR OWN OR ANOTHER MAMMAL SPECIES: SURVIVAL AND THE CAUSES OF MORTALITY
Authors: Streltsov V. V. , Nekrasova M. V. , Maltsev A. N. , Petrin A. A. , Kotenkova E. V.
Published: April 2024

Conditions of rearing pups at an early age render a significant impact on subsequent development, reproduction and certain features of the behavior of mammals including rodents. Parents, mostly lactating females, are the main component of the social environment of pups at the early period of postnatal ontogenesis in most mammal species. Therefore, rearing pups in foster families of their own (in-fostering) or another, even taxonomically distant species (cross-fostering) is one of the main methods of assessing the impact of early experience and maternal environment on the development of animal behavior. Cross-fostering or in-fostering is also used for the conservation of valuable animal species. Therefore, more effective fostering methods that provide the maximum survival of the young are necessary to be developed. According to this, we investigated the survival and possible causes of the mortality of rodent pups representing several species in foster families of their own or another mammal species. We conducted a series of experiments on the cross-fostering and in-fostering of house (Mus musculus) and mound-building (Mus spicilegus) mice, yellow steppe lemmings (Eolagurus luteus) and brown rats (Rattus norvegicus), and on rearing rat pups in foster families of the European polecat (Mustela putorius). The proportion of successfully cross-fostered pups (0–68.4) was lower compared to the in-fostered (93.3–100) ones. This result is presumably explained by more significant differences in the maternal environment when reared by a heterospecific female. According to the literature data, the age of foster and recipient female pups, species-specific differences of odor, the presence or absence of a male and the level of paternal care, the level of stress of the mother and offspring, the expression of maternal instinct, the previous female experience in rearing its own and foster pups, the duration of lactation and the nutritional value of maternal milk are the factors that seem to affect the survival and mortality of foster pups.
NEW SPECIES OF MICROSCOPIC TURBELLARIANS OF THE FAMILY RHYNCHOKARLINGIIDAE (PLATHELMINTHES, KALYPTORHYNCHIA) FROM SOUTHERN LAKE BAIKAL
Authors: Krivorotkin R. S. , Timoshkin O. A.
Published: April 2024

Four new species of microturbellarians (Kalyptorhynchia, Rhynchokarlingiidae), each one representing the genera Cohenella Timoshkin 2004, Coulterella Timoshkin 2004, Mariareuterella Timoshkin et Grygier 2005 and Riedelella Timoshkin 2004 were found when studying the benthic communities at the western coast of the southern basin of Lake Baikal, Siberia. Their illustrated descriptions, comparisons and distributional characteristics are given. All species were found in the coastal zone of the lake, at 1.5–3.8 m depths, on sandy or rocky bottoms.
BIOLOGICAL CHARACTERISTICS AND FOOD COMPOSITION OF THE SHRIMP, SABINEA SEPTEMCARINATA (SABINE 1824) (CRUSTACEA, CRANGONIDAE) FROM THE SHELF OF THE KARA AND LAPTEV SEAS
Authors: Kobiakov K. A.
Published: April 2024

The size and sex structure, the dependence of the state of the gonads of females on the size of the individual, and the composition of the food of the shrimp, Sabinea septemcarinata (Sabine 1824) (Crustacea, Crangonidae) from the Laptev Sea, the Khatanga Bay and the Kara Sea are described (598 individuals: 230 of them had empty stomachs, 368 contained food in their stomachs, and 34 had them full). The shrimps were collected in August–September 2016. The total body length of the shrimps examined varied from 31 to 103 mm: 32–103 mm in females and 31–74 mm in males. The lifespan seems to last 3–4 years in females, vs 2–3 years in males. Based on the condition of the gonads of the females, the time of material collection coincided with spawning. Among the females there are individuals at all stages of the reproductive cycle: feeding, spawning and preparing for the next spawning. This indicates extended population spawning. Sabinea septemcarinata belongs to the life form of burrowing shrimp. According to the frequency of occurrence in the stomachs, detritus takes the first place (92.2%). The second and third places are taken up by cumin crayfish and sedentary polychaetes, which occur in almost every second and third stomach (frequency of occurrence 37.7 and 23.9%, respectively). Sand shows a frequency of occurrence of 50.3%. In the virtual food lump, a little more than a third of its volume is taken up by detritus (39.7%), followed by cumin crayfish and polychaetes that take second and third places (23.6 and 22.6%, respectively). Consequently, S. septemcarinata feed on infauna. Thus, S. septemcarinata are characterized by elements of an attacking predator and a detritophage.
SPATIAL DISTRIBUTION OF GREATER SPOTTED EAGLES (CLANGA CLANGA, ACCIPITRIDAE, ACCIPITRIFORMES) DURING THE WINTERING PERIOD AND FEATURES OF THEIR HABITATS DETERMINED USING GPS-GSM TELEMETRY
Authors: Mischenko A. L. , Pedenko A. S. , Sharikov A. V. , Karvovsky D. A. , Melnikov V. N. , Sukhanova O. V. , Bekmansurov R. H. , Grinchenko O. S.
Published: April 2024

Using GPS-GSM trackers, data on the spatial distribution and habitat features during the wintering period were obtained for five young greater spotted eagles (Clanga clanga) tagged in the center of European Russia or the Middle Volga region. The wintering areas of the studied birds, with the exception of one individual in the second and third winters, were located in the Middle East (Israel, northern Egypt, Saudi Arabia, Iran), in South Africa (Sudan and South Sudan), and in Azerbaijan. An uneven distribution of greater spotted eagles in winter territories was revealed, within which the birds spent most of their time in preferred areas where they stayed for long periods. The size and configuration of winter territories depended on the availability of forage lands. Ecological features of the territories caused a difference in the square of wintering grounds and the character of daytime movements of different individuals. The bird wintering in the arid landscapes of the Arabian Peninsula with extremely poor forage conditions was forced to make maximal daily movements in search of prey. At the same time, individuals wintering in the deltaic Caspian plains in Iran and in the Prikubanskaya Plain in southern Russia found areas with a rich and affordable food which caused minimal daily movements and a minimum radius of the daytime territory. Based on telemetry and visual observations, a previously unknown area of sustainable wintering of greater spotted eagles in the south of European Russia has been localized. The paddy rice fields in the Prikubanskaya Plain as the most important forage habitat and the probable significance of the numerous and available brown rat (Rattus norvegicus) as the main prey species in winter are discussed. The data obtained form an important basis for the development of a strategy for the protection of this rare vulnerable species across the entire distribution range.
THE AVIAN SONG OVER TIME: VARIABILITY AND STABILITY
Authors: Ivanitskii V. V. , Marova I. M.
Published: April 2024

Information is reviewed on the dynamics of bird singing over time, analyzing the rate of change in individual and population repertoires, and considering the factors affecting the rate of such changes. The available data indicate very significant periods of persistence of vocal patterns (song types) in songbird populations. The rate of change in population and individual repertoires is higher in species with an unlimited period of imprinting a song compared to species with a fixed period. The population repertoire of song types in numerous populations inhabiting vast and continuous habitats is more stable than in small and isolated populations occupying structurally fragmented habitats. The most common vocal patterns are the most conserved from year to year, while rare variants often disappear from the population repertoire over time. Abnormal climatic phenomena that cause significant changes in the age composition of populations contribute to rapid changes of dialects. The cases of rapid synchronous changes in vocal repertoires in individuals in local populations, as well as in populations separated from each other by a great distance, are considered in detail. The causes that give rise to this need further research. The most likely reasons may be an exchange of vocal models at wintering grounds or the simultaneous introduction of a large number of migrants into the study populations, which in species with an open training period may cause changes in the repertoire of local individuals also borrowing new vocal models.
THE FIRST DATA ON MICROTURBELLARIANS (PLATHELMINTHES, RHABDITOPHORA) OF THE BOGUCHANSKY RESERVOIR. 1. KALYPTORHYNCHIA OF BAIKAL ORIGIN, WITH DESCRIPTIONS OF THREE NEW SPECIES
Authors: Krivorotkin R. S. , Zaytseva E. P. , Timoshkin O. A.
Published: April 2024

This series of reports is devoted to taxonomic investigations of the microturbellarian fauna (Plathelminthes, Rhabditophora) of the Boguchansky reservoir, lower flow of the Angara River, eastern Siberia. The first report provides information about ten species of Kalyptorhynchia (Rhynchokarlingiidae) previously described from Lake Baikal. Three of them are new species, all described in the present paper. The new species of Kalyptorhynchia belong to the genera Mariareuterella Timoshkin Grygier 2005, Riedelella Timoshkin 2004 and Rhynchokarlingia Timoshkin et Mamkaev 2004, respectively. A species with five cuticular hooks in the male copulatory apparatus is discovered for the first time. The diagnosis of the genus Rhynchokarlingia is expanded. All species are found in the lower reaches of Angara River. Rhynchokarlingiidae is a family of kalyptorhynchian worms autochthonous in Baikal. It seems logical to assume that all newly described species are also of Baikal origin. Endemic Baikal Kalyptorhynchia are found for the first time in an area so remote (about 1400 km) from Lake Baikal. Our records significantly expand the distribution area of Rhynchokarlingiidae, with the Boguchanskoye reservoir of Angara River to be considered as the northern range limit of their distribution. Illustrated descriptions of nine species (including three new ones), comparisons with previously described taxa, information on distribution and brief ecological data are also given.
METHODS FOR STUDYING SONGBIRD TERRITORIES
Authors: Matantseva M. V.
Published: April 2024

A brief historical review is presented of the development of approaches to the study of the territorial space of songbirds (Oscines), using both older and modern research methods. The study of bird territoriality lasts more than a century, but there are still not only little-known aspects that remain in this direction, but also no consensus on terminology and methods. The description of the territorial space plays leading roles in such works. In turn, the classic objects of such research are songbirds demonstrating their territories by singing and defending them from invasion by other individuals. There have been many definitions of the term “territory” proposed, which reflect different concepts of territoriality. The most common definition of a territory thereby is a defended (conceptually) and demonstrated (operationally) space. As a rule, this space is a certain area, a projection of the real territory to the surface on the ground. In recent decades, however, publications have appeared on the topic of exploring territories as three-dimensional (3D) structures. The most effective method of field registration of territories remains the territory mapping method based on visual observations of tagged individuals, which has also been adapted for 3D-territories. Alternative approaches to the registration of territories, including radio telemetry, have significant limitations. In terms of quantitative data-processing methods, there has been a shift over the past decades from an analysis of territories as polygons to their analysis as kernel isopleths. This approach allows for not only the territory contours to be understood, but also the frequency of the use of different points within its limits to be assessed. A significant achievement in the recent years is the adaptation of the kernel methods to three-dimensional structures. It can be said that there is a need to study the territoriality of birds in a 3D-environment. Such research seems very promising because it can provide fundamentally new information on such things as habitat selection and space use, the formation of the spatial and ethological structure of settlements, the separation of territories under high population densities and limited resources, and both intra- and interspecific competition.
HOLOCENE DISTRIBUTION OF THE ASIATIC WILD ASS (EQUUS HEMIONUS, EQUIDAE, PERISSODACTYLA) IN KAZAKHSTAN
Authors: Plasteeva N. A. , Kosintsev P. A. , Shagirbaev M. S. , Devjashin M. M. , Gasilin V. V.
Published: April 2024

The Asiatic wild ass is one of the last wild, free-roaming equid species left in Northern Eurasia. Once widespread across Asia and Eastern Europe, the wild ass is presently listed as a near-threatened species on the IUCN Red List. The conservation of this species is one of important issues of wildlife ecology, while investigating its prehistoric range may provide some perspective into its current distribution and abundance. However, the data available on its past distribution are limited to the last few centuries. We review the available information using both published and unpublished sources to document the sub-fossil sites in Kazakhstan where bones of the species have been reported. Our analysis reveals 70 such sites of Holocene age ranging from Neolithic to modern years. The past range in the Neolithic-Eneolithic and Bronze Age extended from the steppe zone in the north to the desert zone in the south of Kazakhstan. In the Iron Age, remains of Equus hemionus became absent from the fossil record in the northern and central parts of Kazakhstan, thus suggesting a decreased range or abundance of the equid. This coincided with climate changes that occurred during the Bronze–Iron Age transition and the development of nomadic pastoralism. Since the Iron Age human societies in western and central Kazakhstan were predominantly nomadic herders, and livestock impacts on resources could have limited the wild ass distribution. An increased anthropogenic disturbance in 19–20 centuries could eventually have led to population decline in Asiatic wild ass and its extinction in the wild.
SPATIAL AND TEMPORAL HETEROGENEITY OF THE REPTILE ASSEMBLAGE IN WESTERN SIBERIA
Authors: Ravkin Yu. S. , Efimov V. M. , Kokorina I. P. , Chesnokova S. V. , Lyalina M. I.
Published: April 2024

Results of assessing the abundance and distribution of reptiles, which are poorly studied in this regard, are presented in comparison with those on birds and mammals in general and on hunting and commercial species in particular. As a result, data of the spatial and temporal heterogeneity of the reptile populations are unique and of particular value. The studies were carried out over the West Siberian Plain and in the territory of the Altai-Sayan mountainous country. The numbers of reptiles are calculated and their dynamics given across western Siberia. At the same time, bootstrap analysis was used, making it possible to obtain more reliable conclusions on the dynamics of the animal numbers with an insufficient data background. However, the main objective of the study was to identify the main trends in the variability of the reptile populations as a whole. Information concerning the abundance of these animals serves only as the basis for solving this main problem. In addition, the data amassed allow for the dynamics of the numbers of reptiles for certain time periods to be talked about.
COLONIZATION: INDIVIDUAL TRAITS OF COLONISTS AND POPULATION PROCESSES
Authors: Tchabovsky A. V. , Surkova E. N. , Batova O. N.
Published: April 2024

Human activity generates new global processes, including range expansions caused by landscape transformations, climate change, and biological invasions. The study of the causes and processes that accompany the colonization of new areas, as well as its ecological and evolutionary consequences, has been rapidly developing in the last 20 years at the junction between such areas of biology as spatial ecology, ecology of movement, ecology of invasions, metapopulation theory, behavioural ecology, evolutionary ecology, population genetics, and personality research. In our review, we summarize theoretical ideas and empirical studies to answer two main questions: what makes colonists distinguished from the residents of source populations and what specific demographic and genetic processes drive and accompany the wave of population expansion?This research was supported by the Russian Science Foundation (project number 22-14-00223, https://rscf.ru/project/22-14-00223/).
TISSUE ORGANIZATION OF THE MALE REPRODUCTIVE SYSTEM OF THE ACANTHOCEPHALAN, ACANTHOCEPHALUS TENUIROSTRIS (PALAEACANTHOCEPHALA, ECHINORHYNCHIDA)
Authors: Davydenko T. V. , Nikishin V. P.
Published: April 2024

Histological and electron microscopic studies of the male reproductive system of the acanthocephalan, A-canthocephalus tenuirostris show that its organization and structure are generally similar to those characteristic of representatives of the class Palaeacanthocephala. In its composition, paired testes with sperm ducts, which are combined into a common vas deferens, six cement glands, Sefftigen’s pouch, a copulatory bursa and a penis are identified. The distal part of the vas deferens, Sefftigen’s pouch, the bursa and the base of the penis are surrounded by the genital sheath. The shells of the organs of the reproductive system are shown to be formed by fragments of muscle tissue immersed into fibrous intercellular material, which most likely is a derivative of muscle tissue. The most powerful muscle bundles were found in the genital sheath. It appears impossible to confirm the existing opinion concerning a symplastic organization of the organs of the reproductive system in male acanthocephalans.
ARCHITECTONICS OF THE MESONEFROS OF THE SENEGAL POLYPTER (POLYPTERUS SENEGALUS (CUVIER 1829), POLYPTERIFORMES)
Authors: Evdokimov E. G. , Fleurova E. A.
Published: April 2024

Layer-by-layer serial histological sections were used to reconstruct the mesonephros of P. senegalus. The distribution pattern of the structure of both nephron and hematopoietic tissue was shown to be similar to the general structure observed in ray-finned fishes. Most of the hematopoietic tissue of animal origin was revealed to be located at the cranial-ventral pole of the organ. The largest number of renal corpuscles, all with the smallest surface area and located the most distant from one another, was found in the caudal part of the mesonephros. Such an arrangement of the structural units of the kidney, coupled with the high vascularization level of the organ (the position of extraorganic and multiple branching intraorganic vessels), makes it possible to create a sufficiently increased pressure to determine the destination, thus bringing the P. senegalus kidney closer to the amphibian mesonephros. These features could have been evolutionarily fixed in the basal groups of ray-finned fishes and preserved in the process of evolutionary development, manifesting themselves in evolutionarily young species of this group.
Heteroleptic Metal-Organic Frameworks of Lanthanides (Lа, Ce, and Ho) Based on Ligands of the Anilate Type and Dicarboxylic Acids
Authors: Trofimova O. Yu. , Maleeva A. V. , Arsen’eva K. V. , Klimashevskaya A. V. , Cherkasov A. V. , Piskunov A. V.
Published: April 2024

New heteroleptic metal-organic frameworks of lanthanides, units of which contain anionic organic ligands of two types, are prepared by the solvothermal synthesis in N,N-dimethylformamide (DMF). The cross-linked coordination polymer [Ho2(CA)2(Bdc)·4DMF] (I) and two scaffold derivatives [La2(pQ)2(Bpdc)·4DMF] (II) and [Ce2(CA)(Bdc)2·4DMF]·2DMF (III·2DMF), where CA is chloranilic acid dianion, pQ is 2,5-dihydroxy-3,6-di-tert-butyl-para-benzoquinone dianion, Bdc is terephthalic acid dianion, and Bpdc is 4,4'-biphenyldicarboxylic acid dianion, are synthesized. The structures of compounds I, II, and III·2DMF are studied by X-ray diffraction (XRD) (CIF file CCDC nos. 2212230, 2212231, and 2212232, respectively).
Reactions of Triangular Molybdenum and Tungsten Clusters with Tetrabromocatechol
Authors: Petrov P. A. , Filippova E. A. , Giniyatullin V. R. , Sukhikh T. S. , Sheven’ D. G. , Gushchin A. L. , Sokolov M. N.
Published: April 2024

The reaction of cluster complex (nBu4N)2[Mo3Se7Br6] with tetrabromocatechol (H2Tbc) in the presence of Et3N and Ph4PBr results in the formation of (Ph4P)2[Mo3Se7(Tbc)3]∙2MeOH (Ia∙2MeOH). Under the same conditions, the tungsten analogue (nBu4N)2[W3S7Br6] is completely or partly destroyed to give the complex (Ph4P)(Et3NH)[WO2(Tbc)2] (II). The structures of Ia·2MeOH and II were established by X-ray diffraction analysis (CCDC nos. 2213900 and 2213901, respectively). The redox properties of complex Ia and related (Ph4P)2[Mo3S7(Tbc)3] (Ib) and (Ph4P)2[Mo3S7(Tcc)3] (Ic) (Tcc is tetrachlorocatecholate) were also studied by cyclic voltammetry.
Lutetium Cyclopentadienyl Complex with the 2,6-Di-tert-Butylanthracene Dianion
Authors: Roitershtein D. M. , Lyssenko K. A. , Nifant’ev I. E. , Minyaev M. E.
Published: April 2024

The reaction of 2,6-di(tert-butyl)anthracene with potassium graphite and monocyclopentadienyllutetium dichloride tetrahydrofuranate in THF gave the anthracenide complex [(η5-C5H5)Lu(η2-2,6-tBu2C14H8)(THF)2] (I), which was studied by X-ray diffraction (CCDC no. 2215512). Complex I crystallizes in the orthorhombic space group P212121. The structural rigidity of the Lu(O)2Cp(anthracene) crystallographic node was demonstrated. The retention of the structure of complex I in solution was confirmed by NMR techniques.
Heteroleptic Cobalt Complexes with Abnormally Coordinated N-Heterocyclic Carbene
Authors: Petrov P. A. , Nikolaevskii S. A. , Yambulatov D. S. , Sukhikh T. S. , Starikova A. A. , Kiskin M. A. , Sokolov M. N. , Eremenko I. L.
Published: April 2024

The reaction of cobalt pivalate [Co(Piv)2]n and in situ generated N‑heterocyclic carbene IPrPh (1,3-bis(2,6-diisopropylphenyl)-2-phenylimidazol-4-ylidene) affords heteroligand complexes [Co2(Piv)4-(IPrPh)2] (I), [Co2(Piv)2.8(OtBu)1.2(IPrPh)2] (II), and [Co3(μ3-O)(Piv)4(IPrPh)2] (III). The structures of complexes II·C6H14 and III are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2216724 and 2216725, respectively). Exchange spin-spin interactions between the magnetic Со2+ ions in the synthesized compounds are estimated by quantum chemical calculations.
Structure and Magnetic Properties of the Single Crystal of the Liquid-Crystalline Cu(II) Complex with β-Enaminoketone
Authors: Turanova O. A. , Gubaidullin A. T. , Sukhanov A. A. , Frolova E. N. , Kovganko V. N. , Saifina A. F. , Turanov A. N.
Published: April 2024

The structure and magnetic properties of the single crystal of bis{1-[4-(4-pentyloxybenzoyl-oxy)phenyl]-1-amino-3-pentylprop-1-en-3-onate}copper(II), which shows nematic mesomorphism, were studied by X-ray diffraction and electron spin resonance spectroscopy.
Spin Order Transfer from a Parahydrogen Molecule to a Cyanide Ion in the Iridium Complex under the SABRE Conditions
Authors: Novikov V. V. , Zlobina V. V. , Spiridonov K. A. , Nikovskii I. A. , Peregudov A. S. , Kiryutin A. S. , Yurkovskaya A. V. , Polezhaev A. A.
Published: April 2024

A possibility of generating a high degree of spin polarization of 13C and 15N nuclei in the cyanide ion, which forms the coordination bond with the metal ion, using parahydrogen is demonstrated for the first time for the new iridium carbene complex as an example. The spin–spin interaction constants in the synthesized complex and the structure of the hydride intermediate are determined by an analysis of the 13С NMR spectra detected using broadband and selective heteronuclear decoupling. The cyanide ion is shown to coordinate to the metal ion by the carbon atom in one of two equatorial positions, and two pyridine molecules are arranged in the axial and equatorial positions. The signal amplification factors for 13С and 15N nuclei of the cyanide anion (5665 and –49 555, respectively) are estimated by NMR spectroscopy of the polarized substrate using the SABRE method from an ultralow magnetic field of 0.5 μT. This amplification corresponds to 15.5% polarization of nitrogen nuclei achieved within several seconds at room temperature.
Furancarboxylate Coordination Polymers of Gd3+ and Eu3+: Synthesis,
Structural Variations, and Biological Properties
Authors: Uvarova M. A. , Lutsenko I. A. , Shmelev M. A. , Bekker O. B. , Kiskin M. A. , Eremenko I. L.
Published: April 2024

A series of polymer complexes of Gd(III) and Eu(III) with 3-furancarboxylic (HFur) and 5-nitro-2-furancarboxylic (HNfur) acids differed in the composition and coligands presented by solvent molecules(CH3OH/C2H5OH/H2O) is synthesized: [Gd(Fur)3(CH3OH)(C2H5OH)]n (I), [Gd(Nfur)3(CH3OH)2]n·CH3CN (II), [Eu(Fur)3(C2H5OH)]n (III), and [Eu(Nfur)3(H2O)2]n·3CH3CN (IV). According to the X-raydiffraction (XRD) data, all complexes are 1D coordination polymers in which the lanthanide cation has thecoordination number 8 (LnO8) to form the environment as a doubly augmented triangular prism (I, II) or asquare antiprism (III, IV). The supramolecular levels of the polymers are stabilized due to intra- and intermolecularhydrogen bonds between the coordinated solvent molecules and O atoms of the chelate-boundanions of the acid and via two types of noncovalent C–H…O and N–O…π interactions that significantly contributeto an additional stabilization of the crystal packings. The biological properties of complexes I, II, andIV are studied with respect to the model nonpathogenic strain Mycolicibacterium smegmatis.
Triphenylphosphine Thiolate Gold(I) Complexes with Redox-Active Schiff Bases: Synthesis, Electrochemical Properties, and Biological Activity
Authors: Smolyaninov I. V. , Burmistrova D. A. , Pomortseva N. P. , Polovinkina M. A. , Demidov O. P. , Al’myasheva N. R. , Poddel’skii A. I. , Berberova N. T.
Published: April 2024

New gold(I) phosphine thiolate complexes [(Ph3P)Au(SLn)] I–V with Schiff bases LnSH containingredox-active catechol, phenol, or quinone methide moieties were synthesized and characterized. Themolecular structure of compound I in the crystalline state was established by X-ray diffraction (CCDCno. 2237815). The electrochemical behavior of compounds I–V was studieв by cyclic voltammetry. The proposedelectrooxidation mechanism of the complexes involves the Au–S bond cleavage, the disulfide formation,as well as the oxidation of the redox active group of the ligand. In the cathode region, complexes I–IIItend to form relatively stable monoanionic species. The radical scavenging activity of complexes decreases incomparison to free ligands in the reactions with synthetic radicals and the CUPRAC test. Compounds I, II,IV, and V have no clear-cut effect on the promoted DNA damage; however, they show antioxidant actionin the non-enzymatic lipid peroxidation of rat liver homogenate. Compounds I–V demonstrate a weak antibacterialactivity against Staphylococcus aureus strains. The gold(I) complexes cytotoxicity was studied againstA-549, MCF-7, and HTC-116 cancer cell lines using MTT assay. The test compounds are characterized byhigher selectivity to certain types of cells than the sulfur-containing Schiff bases. The presence of quinonemethide moiety in the ligand in case of V significantly increases the cytotoxicity against all of the cell lines.
SYNTHESIS AND FEATURES OF THE MOLECULAR AND CRYSTAL STRUCTURE OF THE Cp4Ru4(µ3-CO)4 CLUSTER
Authors: Osintseva S. V. , Semeikin O. V. , Dolgushin F. M. , Tselukovskaya E. D. , Ananyev I. V.
Published: April 2024

When preparing the ruthenium dimer [Ru(CO)2Cp]2 in the thermal reaction of cyclopentadiene with Ru3(CO)12, the tetranuclear cluster [Ru(μ3-CO)Cp]4 (I) was obtained as a minor product. Spectral (13C and 1H NMR, IR) and structural studies were carried out for cluster I. By crystallization under different conditions, two types of dark cherry crystals were obtained, cluster I itself (crystal 1) and its tetrahydrate (crystal 2), the structure of which was determined by X-ray diffraction. Structural data for 1 and 2 have been deposited in the Cambridge Structural Data Center (CCDC nos. 2241197 and 2241199, respectively; deposit@ccdc.cam.ac.uk; http://www.ccdc.cam.ac.uk). Based on a comparative analysis of cluster geometry, it is shown that the distortion of the Ru4(CO)4 framework in I from ideal Td symmetry in the structure of a pure compound is determined by the anisotropy of intermolecular contacts in the crystal. Features of chemical bonding in the [Ru(μ3-CO)Cp]4 cluster and its iron-containing analogue were studied using DFT calculations using topological analysis of electron density to compare energy characteristics and effective force constant bonding interactions. The necessity of using criteria for elastic deformations of interatomic interactions (force constants) for the correct description of structural and chemical phenomena, for example, such as the structural non-rigidity of the framework of transition metal clusters, has been demonstrated.
The Search for Domestic Pharmaceutical Substances among Metal Complexes Based on (Hetero)arylamides of 4-Aryl-2-hydroxy-4-oxo-2-butenoic Acids
Authors: Pulina N. A. , Sobin F. V. , Krasnova A. I.
Published: April 2024

The data obtained on the synthesis and search for biological activity among metal complexes based on 4-aryl-2-hydroxy-4-oxo-2-butenoic acid (hetero)arylamides were integrated. The data on the antimicrobial, anti-inflammatory, analgesic, hypoglycemic, antihypoxic, and immunotropic activities of the synthesized compounds were analyzed. The relationship between the chemical structure and biological activity of chelate complexes was discussed and some regular features were identified. Promising compounds for further research and development of new domestic pharmaceutical substances were found.
Heteroligand Zn(II) Metal-Organic Frameworks Based on 4-Substituted 4,2':6',4"-Terpyridine Derivatives and Terephthalates
Authors: Zaguzin A. S. , Mahmoudi G. , Zubkov F. I. , Bondarenko M. A. , Zherebtsov D. A. , Val’chuk K. S. , Abramov P. A. , Fedin V. P. , Adonin S. A.
Published: April 2024

Metal-organic frameworks based on Zn(II) and 4-substiuted 4,2':6',4"-terpyridine, terephthalate (Bdc), and 2-iodoterephthalate (2-I-Bdc) derivatives, {[Zn3(FurTerPy)2(Bdc)6]} (I), {[Zn(FurTerPy)(2-I-Bdc)}] (II), and {[Zn(PyrrTerPy)2(Bdc)} (III), were prepared and characterized by X-ray diffraction.
Dielectric Model of the Upper Organic Layer of Forest Soils for a Frequency of 435 MHz
Authors: Karavayskiy A. Yu. , Lukin Yu. I.
Published: April 2024

A single-frequency refractive dielectric model is proposed for thawed and frozen forest organic soils in the root zone at 435 MHz. The dielectric model was created on the basis of the laboratory dielectric measurements of four soils with organic matter content in the range from 15 to 31%. Dielectric measurements were carried out in the range of the gravimetric moisture from 0 to 0.6 g/g and temperature range from –30 to 25°С. The coefficient of determination (R2) between the predicted and measured values of the real (ε') and imaginary (ε") parts of the complex permittivity was 0.97. The normalized root-mean-square error was 16% and 21% for the real and imaginary parts of the complex permittivity, respectively. The created dielectric model may be applied in algorithms for remote sensing of forest soil moisture in the root zone using radar and radiometric data.
Evaluation of the NDVI Index as a Source of Information on Aboveground Phytomass in Steppes
Authors: Kalmykova O. G. , Dusaeva G. Kh. , Khoroshev A. V.
Published: April 2024

The complexity of phytomass measurements on sample plots hinders the extrapolation of plot-related data to areas comparable to land use or landscape units. Vegetation indices calculated from satellite images are usually considered as indicators of green phytomass and are used for its areal estimates. The study solves the problem of establishing the information content of the normalized difference vegetation index NDVI depending on the fractional structure of living and dead aboveground phytomass, seasonal dynamics of the biological cycle, hydrothermal conditions and landscape position. We used the results of monthly measurements of aboveground phytomass fractions at 13 sites covered by Stipa zalesskii and Stipa lessingiana formations in the Burtinskaya steppe (Orenburgsky nature reserve) from May to September in 2015–2020. For each period, NDVI values were calculated from Landsat satellite images at all sites. Hypotheses about geobotanical, hydrothermal, phenological and landscape factors of NDVI informativity were tested by using the Spearman correlation coefficients, analysis of variance and multiple regression. The discrepancy between the seasonal peaks of NDVI and green phytomass is not consistent with the common opinion of a direct indicator value of NDVI. The total live biomass correlates more clearly with the index in June and July but weaker at the end of the season. NDVI turned out to be sensitive not so much to green phytomass as such, but to the mass and proportion of forbs and the ratio of live and dead phytomass. In late spring and early summer, NDVI is most closely associated with forbs while in July – with grasses. The hypothesis about the possibility of screening green mass with standing dead biomass was confirmed, which leads to a decrease in NDVI despite the absence of a decrease in green phytomass. NDVI may underestimate the real green phytomass if there is a sharp increase in the mass of dead biomass, usually in the second half of summer and early autumn. NDVI more adequately reflects the state of the aboveground phytomass of steppe communities that have not been exposed to fires for a long time, compared to burned communities and fallows.
Soil Moisture Estimation by Radar Data Based on Multiple Regression
Authors: Rodionova N. V.
Published: April 2024

The task of soil moisture assessing by remote (satellite) methods remains relevant up to the present time. Regression models based on the correlation of radar data with ground measurements of soil moisture are constructed to assess soil moisture in the work. Ground-based measurements were taken at two stations in Germany (Falkenberg and Gevenich), which are part of the ISMN (International Soil Moisture Network) worldwide soil moisture data network. Sentinel-1 satellite data is used as radar data. Multiple regressions with a determination coefficient up to 0.91 are constructed. It is proposed to use not only radar, but also meteorological data in regressions, which allows increasing the coefficient of determination and reducing the standard error of regression. For the possible spread of regressions obtained for one territory to another territory, two criteria are selected: the proximity of the values of the Selyaninov hydrothermal coefficient and the similarity of the soil texture. According to these conditions, two stations in the Ryazan region and in Kalmykia were chosen, whose archival information on soil moisture is contained in the ISMN database up to 1998. Each of the selected stations satisfies only one of the criteria.
Second-order optical differentiator based on a composite metal–dielectric–metal structure
Authors: Kashapov A. I. , Bezus E. A. , Bykov D. A. , Doskolovich L. L.
Published: April 2024

Optical properties of a composite structure consisting of two sequentially arranged three-layer metal-dielectric-metal structures (MDM-structures) are considered. It is shown that such a composite MDM-structure can perform second-order spatiotemporal differentiation with high quality at normal incidence. The obtained results can find application in creating systems for analog optical computing and optical information processing.
Two-dimensional graphene superlattice conductivity control by transverse electric fields
Authors: Glazov S. Yu. , Mescheryakova N. E. , Podgornaya I. A.
Published: April 2024

The possibility of controlling the conductivity of a graphene superlattice by transverse constant and alternating electric fields due to the nonadditivity of its energy spectrum is investigated. A technique is proposed for identifying the parameter areas of the applied fields in which conductivity control is most effective.
The effect of entrainment of electrons by a breather in a graphene-based superlattice
Authors: Badikova P. V. , Zav’yalov D. V. , Konchenkov V. I. , Kryuchkov S. V.
Published: April 2024

The breather electric effect in a graphene superlattice has been studied in the collisionless approximation. When calculating the drag current density, an approximate solution in the form of a small-amplitude traveling breather of the nonlinear Klein–Gordon equation describing the propagation of nonlinear waves in a graphene superlattice is used. The breather travel time due to collisional dissipation is estimated.
Investigation of the possibility of the existence of multistability in the regime of intermittent phase synchronization in ensemble of unidirectionally coupled Rössler systems
Authors: Khanadeev V. A. , Plotnikova A. D. , Moskalenko O. I.
Published: April 2024

The question of the possibility of the existence of multistability near the boundary of phase synchronization in unidirectionally coupled chaotic systems is studied. The cases of relatively large and relatively small detuning between them are considered. The multistability is shown to be observed in both cases. A quantitative characteristic of the degree of multistability is introduced and it is shown that its time dependence in the regime of intermittent phase synchronization can be used to determine the lengths of the characteristic phases of the system behavior.