Severtsov Institute of Ecology and Evolution

A new species, Mallomonas decipiens sp. nov., is described from Vietnam based on silica-scale morphology observed using scanning and transmission electron microscopy. Mallomonas decipiens belongs to section Papillosae and is most similar to M. korshikovii, M. delanciana and M. verrucosa. Scales of M. decipiens have a shallow elongated dome, which is recessed from the distal margin, papillae on the dome and anterior flanges, and the open reticulation on the shield. Bristles of the newly described species are short, with a bifurcated apex and a flattened foot. The new species has been found in eight localities in six provinces from the northern to the southern parts of Vietnam.

A checklist of oribatid mites (Oribatida) registered in Ethiopia is presented, based on published literature from 1916 to 2025. It includes the names of species, their general known distribution, distribution by regions and habitat in Ethiopia, and references. A total of 375 species/subspecies, belonging to 165 genera, 72 families, 32 superfamilies, and five infraorders, is given. The proportion of Brachypylina is 311 species/subspecies (83%). Most of the species/subspecies (337) were recorded for the first time in the Ethiopian fauna in 2010–2025. Among oribatid species, 121 species are known only from Ethiopia, 150 species are Afrotropical, and 104 species have a wider distribution. Many species were found in litter-soil in various forest associations. Considering that there is no significant knowledge for some Ethiopian regions and habitats, a large number of new species and distribution/habitat records could be discovered in the future.

Cementum and dentin increment analysis and dental microwear analysis were used for the first time to study the dental remains of a giant brown bear (Ursus arctos) from the Late Pleistocene of Yakutia, Russia. Dental increment analysis showed that this bear died during the warm season (May–Sep) in the prime of its life—at the age of 15+ years. Dental microwear analysis inferred that this bear had a varied diet consisting of a wide range of plant items, varying from soft-mast during warm season to hard-mast during hyperphagia period, but with regular intake of animal protein throughout the year. Diet in the last few weeks before death was inferred as mainly herbivorous and mainly comprising soft-mast abrasive grasses. Data on vegetation and climate in the territory of Yakutia during the Late Pleistocene, and comparisons with the dietary habits of extant U. arctos from Yakutia, allowed us to narrow the period of death of the animal within the warm season. The exceptionally large size of the bear combined with its omnivorous diet may indicate favorable living conditions for brown bears in the Mammoth steppe of Yakutia.

DNA identification results for certain alien fish species in the Volga-Kama basin are presented. We have revealed different genetic structures among these alien species, which reflect the varying histories of their appearance in the Volga and Kama basins. The observed genetic differentiation of some species is likely related to isolation during transgression and degradation of the Pontic Lake-Sea in the post-Miocene period. The current stage of faunal mixing is associated with the dispersal of hydrobionts beyond their historical ranges through corridors newly formed as a result of human activities. The use of DNA barcoding helped to elucidate the genetic structure of po pulations of several fish species alien to the Volga and Kama. In general, our results did not confirm the advisability of excessively splitting species into the “Azov-Black Sea” and “Caspian” taxa.

The deep evolutionary relationship between humans and intestinal parasites offers opportunities for the reconstruction of diet and living conditions in archaeological populations. Here, the authors identify eggs preserved in sediment adhering to the surface of the sacrum in Muslim burials from the Southern Necropolis at Deraheib (upper reaches of Wadi al-Allaqi, Sudan, ninth–eleventh centuries AD). Species-level identification is suggested based on egg morphology and religious taboos, revealing a high prevalence of infection by Taenia saginata , the beef tapeworm, and contributing to our understanding of diet, subsistence, climate and health in the medieval Nubian Desert.

Under the current global biodiversity crisis, there is a need for automated and noninvasive monitoring techniques that can gather large amounts of data cost-effectively at various ecological scales, from local to large spatial scales. These data can then be analyzed to inform stakeholders and decision-makers. One such technique is passive acoustic monitoring, which is commonly coupled with automatic identification of animal species based on their sound. Automated sound analyses usually require the training of sound detection and identification algorithms. These algorithms are based on annotated acoustic datasets which mark the occurrence of sounds of species inside sound recordings. However, compiling large annotated acoustic datasets is time-consuming and requires experts, and therefore, they normally cover reduced spatial, temporal, and taxonomic scales. This data paper presents WABAD, the World Annotated Bird Acoustic Dataset for passive acoustic monitoring. WABAD is designed to provide the public, the research community, and conservation managers with a novel and globally representative annotated acoustic dataset. This database includes 5047 min of audio files annotated to species-level by local experts with the start and end time and the upper and lower frequencies of each identified bird vocalization in the recordings. The database has a wide taxonomic and spatial coverage, including information on 91,931 vocalizations from 1192 bird species recorded at 72 recording sites in 29 recording locations (mainly countries) and distributed across 13 biomes. WABAD can be used, for example, for developing and/or validating automatic species detection algorithms, answering ecological questions, such as assessing geographical variations on bird vocalizations, or comparing acoustic diversity indices with species-based diversity indices. The dataset is published under a Creative Commons Attribution 4.0 International license that permits redistribution and reuse on the condition that the original work is properly credited.

The species composition and distribution of juvenile fish in the pelagic zone of the Kara Sea in the ice formation period are described for the first time. In October 2023, fry and late larvae of nine fish species from six families were found in the catches of DSN (double-square micronectonic) and Bongo nets. The Arctic cod Boreogadus saida was the most abundant: its fry were concentrated at densities of 1–3 ind./m2 in the northeastern Kara Sea, above the Central Kara Plateau. The second most abundant species was capelin Mallotus villosus, its late larvae were recorded above the St. Anna Trough and in the southwestern Kara Sea on the border with the Barents Sea. For the first time, fry of Atlantic cod Gadus morhua were found in the pelagic zone of the Kara Sea. Only Arctic–boreal species were found in the southwestern part of the sea, while both Arctic–boreal and Arctic species were found in the northeastern part. This is explained rather by seasonal succession and features of hydrological processes than by the borealization process.

Common bottlenose dolphins ( Tursiops truncatus ) are among non-human mammals that possess the ability for vocal production learning, which strongly depends on learning from conspecifics. The hearing sensitivity and acoustic signals of a 4-year-old captive-born bottlenose dolphin suspected of severe hearing loss were investigated. True deafness was confirmed using a non-invasive auditory evoked potential (AEP) recording method in response to rhythmic click stimuli. The deaf dolphin showed no response compared to normal-hearing animals. The vocal repertoire of the deaf dolphin was analyzed and compared to that of two normal-hearing conspecifics. Acoustic activity recordings of the dolphins were conducted individually in a partially isolated pool. The deaf dolphin produced whistles, clicks and burst pulses typical of bottlenose dolphins. However, his whistles were primarily combined with clicks, and we could not identify his individually distinctive signature whistle. Besides, the three dolphins shared a unique combined signal. The fundamental frequency of its flat whistle component matched the frequency of the trainer’s bridge signal. Our results indicate that the dolphin’s deafness likely occurred after birth, prior to signature whistle development. This research provides valuable insights into the impact of hearing loss on acoustic signalization in bottlenose dolphins.

Essential oils (EOs) of Mentha spicata var. crispa (Benth.) Danert and M. × piperita var. citrata (Ehrh.) Briq. and EO components are widely used in medicine, pharmaceuticals, cosmetics, hygiene products, the food industry, and other fields, and have a high commercial value. The variety Mentha spicata var. crispa is also used as an ornamental plant due to its distinctive curled leaves. Studying the influence of growing conditions and harvest timing on EO yield and the major compound concentrations is one of the key research directions for Mentha species, aimed at the ascertainment of the ways of increasing EO production and quality. Gas chromatography analysis of the component composition of EOs from leaves of Mentha spicata var. crispa “Kurchavaya” (MscK) showed that it remained stable both in July and September, with carvone predominating (81% and 85%, respectively). In contrast, the EO composition from M. × piperita var. citrata “Apelsinovaya” (MpcA) leaves changed in the course of the vegetation period. In July, menthofuran dominated (30%), while in September, linalool and its acetate were predominant (34% and 47%, respectively), which was typical for this chemotype. At the same time, the content of EOs and the density of glandular trichomes (GTs) (the OE storage sites) in MscK were higher in July and decreased by September, whereas in MpcA, both EO content and the number of GTs increased from July to September. These changes may have been caused by temperature fluctuations. Thus, MscK proved to be more resistant to environmental factors than MpcA.