Vol 102, No 7 (2023)

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.

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).

Symbiotic invertebrates play crucial roles in coral reef ecosystems due to their extremely high abundance and biomass, and by maintaining coral fitness and protecting them from predation. Among these invertebrates, symbiotic crabs of the family Trapeziidae are especially important for branching corals of the family Pocilloporidae. In this research, we studied the spatial arrangement and parameters of the populations of the symbiotic crab, Trapezia septata at the early stage of Pocillopora verrucosa colony formation. The study was conducted based on symbionts sampled from small coral colonies exposed for three months at a coral nursery in the Nha Trang Bay, Vietnam. As much as 59.5% of the study colonies are shown to be inhabited by the T. septata crab. The percentage of inhabited colonies grows proportionately to their volume. The male to female ratio is 1.4, being skewed to males. The number of males and females is increased with the volume of inhabited colonies, as is the average size of individuals. Individual colonies are commonly inhabited by a single crab or heterosexual pairs. Sexual dimorphism was found, females being larger than males. A positive relationship between the sizes of males and females in pairs was revealed, as in 73% pairs females were larger than males. The size of the clutch correlated positively to the size of the female. We hypothesize that the predominance of males in the population, as well as the individuals located among the hosts one by one, is the result of intersexual competition

The assemblage of hymenopteran parasitoids associated with the invasive lime leaf miner, Phyllonorycter issikii (Lepidoptera, Gracillariidae) developing on the lime (Tilia cordata) was studied in the Kurgan Province (Madvezh’ye Lake), and in the cities of Tobolsk, Omsk, and Novosibirsk during 2018−2019. Twenty-one species of parasitoids of Ph. issikii were recognized: Pteromalus sp. (Pteromalidae), Cirrospilus diallus, Elachertus sp., Hyssopus geniculatus, H. nigritulus, Pnigalio mediterraneus, Pnigalio sp., Sympiesis dolichogaster, S. gordius, S. sericeicornis, Chrysocharis laomedon, Ch. pentheus, Ch. pubicornis, Ch. viridis, Chrysocharis sp., Neochrysocharis formosus, Minotetrastichus frontalis (Eulophidae), Colastes braconius, Apanteles sp., Pholetesor circumscriptus and Cotesia sp., (Braconidae). Chrysocharis viridis has been reported as a parasitoid of lime leaf miner for the first time. The role of the complex of parasitoids in the mortality of the miner is negligible, the mortality rate ranging from 1.9 ± 0.4 (Novosibirsk) to 23.7 ± 3.3% (Omsk).

The Polar bear’s seropositivity from the Barents Sea subpopulation to a number of pathogens was analyzed: Canine distemper virus, Herpes simplex virus, Parvovirus, Toxoplasma, Trichinella (Trichinella sp.), Mycoplasma (Mycoplasma sp.), Candida (Candida sp.) and Chlamydia (Chlamydia sp.). Seropositive animals have been identified for Canine distemper virus and Trichinella (Trichinella sp.). The proportion of seropositive animals to Trichinella was the maximal. Over the last 10 years, an increased share of animals seropositive to Trichinella and Canine distemper virus has been noted in the study area.

The East European vole is a facultative synanthropic species that actively spreads in the eastern part of northern Eurasia. The distribution area of the species in the Irkutsk Oblast’ has been known as a disjunct part of the range since the 1980s. Our dataset includes 98 individuals caught in 2016–2017 and 2021–2023 in the eastern segment of the species’ dispersal area, where the East European vole was first discovered in the early 2010s. Animals were caught in anthropogenically transformed areas spanning from the outskirts of the city of Irkutsk to kilometer 23 of the Goloustnensky Tract; trapping in natural biotopes revealed no M. rossiaemeridionalis. Species identification was based on molecular genetic markers. Morphological and fine structural characteristics of molar teeth were studied using both light and scanning electron microscopy. The complexity of the occlusal surface, the alternation patterns of the enamel cutting edges (occlusal regularity), and the presence or absence of atypical extra elements such as prismatic folds and prisms in places of the early cricetid dental features were assessed. The estimates of complexity and regularity patterns fell within the range of dental variability known for the continuous distribution area of the species. The atypical extra elements on molars were described for the first time in M. rossiaemeridionalis based on material coming from two trapping sites. The extra elements were confined to the posterior lobes of the lower molars, where an additional reentrant angle separated an extra prism in place of a hypoconid. Enamel walls of the extra prism showed an inversion of the enamel types (a thin layer of radial enamel on the anterior wall and a thick layer of lamellar plus radial enamel on the posterior wall) that was contrary to the evolutionary patterns and functional requirements known for Microtus. The local micropopulation studied is concluded to show phenotypic consequences of a reduced number of founders. Apparently, the species could have faced sequential establishment events in the study area. Our results indicate that dental features are useful for monitoring the arvicoline species, the distribution limits of which are subject to significant spatial changes in the relatively short time intervals available for observation.