Vol 103, No 5 (2024)

When studying the zooperiphyton of reservoirs and watercourses in the Subarctic of Western Siberia, freshwater sponges were identified. The research was carried out in areas of the southern tundra and forested tundra belts, which in turn were conditionally divided into three zones: western, central and eastern. In total, the research covered 40 reservoirs and watercourses. Three species of sponges have been found: Spongilla lacustris, Ephydatia muelleri and Ephydatia fluviatilis. The most common species is S. lacustris, E. muelleri being less common, vs E. fluviatilis which occurs only occasionally. The maximum numbers of species and their occurrence were noted in forested tundra water bodies. Linear measurements and a dimensional analysis both of gemmules and elements of the skeleton of the sponges were carried out. A tendency was revealed to a decrease in size of the skeletal structures of the studied biological material in comparison with literature data.

Two new species of the gelechiid moth genus Photodotis Meyrick are described from Sumatra, Indonesia: P. ketambensis sp. n. and P. kedahensis sp. n. In addition, the species P. crockeri M. Omelko et N. Omelko and P. imperfecta M. Omelko et N. Omelko, both described earlier from Borneo Island, Eastern Malaysia, are recorded from Sumatra for the first time.

Studies on local forms of the Sandy sculpin, Leocottus kesslerii, in the lakes Baikal, Arakhlei and Gusinoye show that the differences between lake forms in terms of external morphology lie in the head length to width ratio. In the Baikal form, the head is wider than long, vs the opposite in both Apakhlei and Gusinoe forms. In the Baikal and Gusinoe forms, there is a gap between the dorsal fins, a gap being absent from the Arakhlei form and the dorsal fins are in touch with each other. In the Arakhlei form, the anal fin is long (37.4–43%, on average 39.3% SL). In the Baikal form, the length of the A base reaches 32.9% SL (29.0–34.5%). In the Baikal and Arakhlei forms, small and sparse bone prickles are present on the body, these being large and dense in the Gusinoe form. The differences identified show a low level of morphological isolation of the forms. More significant differences are established in ecological features: growth rate, food spectrum, reproductive characteristics, and fecundity values. The differences in ecological features are due to the adaptation of the Sandy sculpin forms to specific conditions of the lakes they inhabit. Studies on genetic differentiation were carried out using the control region (CR) of mtDNA. The study forms of the Sandy sculpin revealed weak genetic isolation. The p-distances between the L. kesslerii forms averaged from 0.33 ± 0.12 to 0.51 ± 0.24%. Such low values of genetic distances clearly lie within the limits of intraspecific variability. The data obtained on the morphological, ecological and genetic differentiation of lake forms of the Sandy sculpin show that fish from the lakes Baikal, Arakhlei and Gusinoe belong to the same nominative subspecies, Leocottus kesslerii kesslerii.

Throughout the 20th century and the first decades of the current century, the Mute Swan, Cygnus olor, has been growing in numbers and expanding its range both northward and northeastward. The history of the species’ settlement to the Northwest of Russia and the main stages of its expansion, as well as the peculiarities of its spatial distribution in the region are discussed. The Mute Swan started breeding in northwestern Russia in the mid-1980s. The species settled in two landscapes: on shallow eutrophic lakes and on sea moraine and selga islands. To date, the species’ range covers the eastern part of the Gulf of Finland, the west and southwest of the Leningrad Region, the whole Pskov Region, and the westernmost parts of the Novgorod and Tver regions. It is noteworthy noting that at the initial stages of expansion the first breeding pairs appeared throughout most of the above-mentioned territories at once. Subsequently, new nests were recorded mainly within the “occupied zone” delineated by the first newcomers. During more than 30 years of expansion, the range of the species moved eastwards by no more than 88–94 km at different localities, while during the previous 20 years (1960–1980) the Mute Swan’s range in Scandinavia moved up to 998 km. Decreasing rates of range expansion amid a continued development of a warm phase of the climate suggest the presence of some kind of climatic barriers for the species in the region.

For the first time, using light and scanning electron microscopy, the fine structure of the skin and its derivatives (glands, hairs, whiskers) was studied in adult male and female Tibetan hamsters (Urocricetus kamensis Satunin 1903), a unique species of the subfamily Cricetinae that lives only in the highlands of the Tibetan Plateau. A comparative morphological analysis of the skin, along with features of its similarity with the skin of other hamsters, revealed a number of characteristic features in the Tibetan hamster that contribute to the adaptation of this species to the harsh mountain climate conditions with sharp seasonal and daily temperature fluctuations: abundant subcutaneous fatty tissue, a special hair structure that provides effective heat protection due to a significant change in the volume of inert air in the fur: significant hair density, wavy arrangement of rows of hairs and the profile of the lower sections of the guard hairs. The presence of relatively long and thick guide hairs in the fur serves to protect the coat in rocky habitats. The array of specific skin glands is little compared to other Cricetinae; no mid-ventral and flank glands were found, this being unique for representatives of the subfamily, but this requires confirmation based on more abundant material.

An analysis of disparity of the anterior portion of m1 shape in the gray voles in an artificial sample consisting of 5 groups with different frequency distributions of 5 morphotypes was carried out. Two main approaches were applied: (a) traditional analysis of frequency distribution of discrete morphotypes and (b) geometric morphometrics (GM) based on a strictly quantitative description of the shape of anterior portion of m1. The groups were compared quantitatively: Cavalli-Sforz–Edwards’ coefficient was applied in the first case, while the thin plate spline and Procrustes analyses in the second; their results were analyzed using a number of standard statistical methods (dispersion analysis, discriminant analysis, multidimensional scaling). Disparity within the groups was assessed using Shannon entropy index and averaged Procrustes distance. Traditional and GM approaches were shown to provide very similar results, with GM having a number of important advantages by being strictly quantitative. The second approach is recommended as the basic to replace the traditional one for explorations in disparity of tooth crown shape in the voles.