Vesicomyid bivalves are a consistent component of communities of sulphide-rich reducing environments distributed worldwide from 77° N to 70°S at depths from 100 to 9050 m. Up-to-now the taxonomy of the family has been uncertain. In this paper, the current state of vesicomyid taxonomy and distribution at the generic rank are considered. This survey is founded on a database including information both from literature sources and also unpublished data of the authors on all recent species of vesicomyids. We suggest that the Vesicomyidae is not a synonym of Kelliellidae, and is therefore a valid family name. We propose to divide the family Vesicomyidae into two subfamilies: Vesicomyinae and Pliocardiinae. The Vesicomyinae includes one genus, Vesicomya, which comprises small-sized bivalves characterized by non-reduced gut and the absence of subfilamental tissue in gills. Symbiosis with chemoautotrophic bacteria has, so far, not been proved for Vesicomya and the genus is not restricted to sulphide-rich reducing habitats. The subfamily Pliocardiinae currently contains about 15 genera with mostly medium or large body size, characterized by the presence of subfilamental tissue in the gills. The Pliocardiinae are highly specialized for sulphide-rich reducing environments, harbouring chemoautrophic bacteria in their gills. This is the first summary of the generic structure of the family Vesicomyidae that allow us to analyze the distribution of vesicomyids at the generic level. We recognize here five different distribution patterns that are related to the specific environmental demands. The general trends in the distribution patterns of the vesicomyids are an occurrence of the majority of genera in broad geographical ranges and the prevalence of near continental type of distribution.

The genus Calyptogena (Bivalvia: Vesicomyidae) comprises highly specialized bivalves living in symbiosis with sulphur-oxidizing bacteria in reducing habitats. In this study, the genus is revised using shell and anatomical features. The work is based on type material, as well as on the extensive collection of vesicomyids obtained during twelve expeditions to the Pacific and Indian Oceans. Nine Recent species are ascribed to the genus Calyptogena, four of which are new: C. pacifica Dall, 1891, C. fausta Okutani, Fujikura & Hashimoto, 1993, C. rectimargo Scarlato, 1981, C. valdiviae (Thiele & Jaeckel, 1931), C. gallardoi Sellanes & Krylova, 2005, C. goffrediae n. sp., C. starobogatovi n. sp., C. makranensis n. sp. and C. costaricana n. sp. The characteristic features of Calyptogena are: shell up to 90 mm in length, elongate-elliptical or elongate; presence of escutcheon; presence of broad posterior ramus (3b) of right subumbonal cardinal tooth as well as right posterior nymphal ridge; absence of pallial sinus as a result of attachment of intersiphonal septal retractor immediately adjacent to ventral surface of posterior adductor; absence of processes on inner vulva of inhalant siphon; presence of inner demibranch only, with descending and ascending lamellae with interlamellar septa not divided into separate tubes. The most closely related taxa to Calyptogena are probably the genus Isorropodon Sturany, 1896, and the group of species represented by ‘Calyptogena’ phaseoliformis Métivier, Okutani & Ohta, 1986. These groups have several characters in common, namely absence of pallial sinus, presence of single inner pair of demibranchs and absence of processes on inner vulva of inhalant siphon. The worldwide distribution of the genus Calyptogena suggests that methane seeps at continental margins are the major dispersal routes and that speciation was promoted by geographical isolation. Recent species diversity and fossil records indicate that the genus originated in the Pacific Ocean. Sufficient data to discuss the distribution at species level exist only for C. pacifica, which has a remarkably narrow bathymetric range. Published studies on the physiology of C. pacifica suggest that adaptation to a specific geochemical environment has led to coexisting vesicomyid genera. The bacteria-containing gill of C. pacifica and other Calyptogena species is one of the most specialized in the family Vesicomyidae and may reflect these ecological adaptations.

Megafauna from the Charlie–Gibbs Fracture Zone (northern Mid-Atlantic Ridge) based on video observations from submersibles was analysed. Species composition was examined, frequency of species occurrence on the fracture wall and its base (depth range from 1740 m to 3100 m) and density of megafauna in the depression at the fracture zone bottom (4200–4500 m depth) were evaluated. At depths between 1700 and 2500 m hexactinellid sponges were most common and diverse. Deeper parts of the wall and its base were dominated by anthozoans (especially gorgonian corals) and echinoderms. A set of dominant species in the lower bathyal in the study area was different from that on the lower continental slope in the north-east Atlantic (Porcupine Seabight). An important contribution to local species richness of ‘rare’ species was demonstrated. The elpidiid holothurian, Kolga nana, occurred at high density in the abyssal depression.

The Piip Volcano is a submarine volcanic edifice occupying the central part of the Volcanologists Massif in the southwestern Bering Sea, with two tops, southern and northern. The minimum depth of the northern top is located at 368 m, and of the southern at 464 m. Active hydrothermal venting occurring at both summits of the volcano supports diverse biological communities, including animals specific for chemosynthetic habitats. In benthic organisms inhabiting the northern and southern tops of the Piip Volcano, for the first time, we examined distribution patterns of the following trace elements: titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, arsenic, selenium, zirconium, molybdenum, silver, cadmium, antimony, barium, tungsten, lead, bismuth, and uranium. The element contents were quantified by the ICP-MS. Total carbon (TC) and total inorganic carbon (TIC) were determined using a Shimadzu TOC-L-CPN and mineral composition of sediment was determined using the XRD. In the water of the biotope from the northern top, concentrations of Mn, Zn, Ag, Cd, Sb, W, Pb were 2–6 times, and Ba was 50 times higher than those from the southern top. This was attributed to the lower temperature of fluids emanating at the southern top. An abundant population of Calyptogena pacifica (Bivalvia: Vesicomyidae: Pliocardiinae) was found only at the southern top. The main target of most trace elements, such as Fe, V, Cr, Co, Ni, Zn, As, Mo, Ag, Cd, W, Pb, Bi, and U were the soft parts of Calyptogena pacifica (with high TOC content, on average 53.1% in gills and 49.6% in the rest of the body). Gills were characterized by particular high contents (>100 µg g⁻¹ dry w.) of Zn, Cd, Fe, Ni, Cu, and Pb, which can form sulphides or be associated with them. Shells of C. pacifica, as well as Brachiopoda, were depleted in these elements, as well as tissues of the carnivores Paguridae (Crustacea) and Actiniaria (Anthozoa). In suspension feeders from both tops, the lower contents of most elements were detected. Estimation of Biological Concentration Factor (BCF) for most elements varied from 10² to 10⁴, reaching n10⁵ for Ni, Zn, Ag, Cd, and Pb. A significant difference in BCF values between Fe and Mn was revealed.

The aim of the study was to determine the clinical and psychopathological characteristics of non-suicidal self-injury (NSSI) in personality disorder (PD) in the comparative age-related aspect during the coronavirus infection (COVID-19) pandemic. Patients and methods: a total of 230 patients (177 males and 53 females) aged 16–25, diagnosed with PD and NSSI behavior manifestations, were studied retrospectively in mental hospital and outpatintly by using clinical-psychopathological method. All patients were divided into two equal groups of 115 people each. Group I was examined in 2017–2019, Group II — in 2020–2021 during the coronavirus infection (COVID-19) pandemic. Results: common features established in both groups were as follows: affective instability, alexithymia, conflict relations with significant others, and current traumatic experience. For a comparative assessment of NSSI in patients of both groups, we used the NSSI typology in adolescent PD, previously developed by the authors. Impulsive, demonstrative, addictive, depersonalizing and self-destructive types of NSSI were recognized as significant for the diagnostic assessment. In the second group of patients, that is, during the period of the COVID-19 pandemic, a change in the selected variants of NSSI was found, that is, in borderline and narcissistic PD the impulsive type was replaced by a demonstrative type, and in schizoid and anxious PD it turned into an addictive one. For a comparative assessment of NSSI in patients of both groups, we used the NSSI typology in PD in adolescence, previously developed by the authors. When assessing suicidality in group II, it was revealed that in most types of PD, with a decrease in the number of suicidal attempts, there was a noticeable increase in the incidence of NSSI with demonstrative suicidality, which correlated with the trajectories of the identified variants of NSSI. Conclusions: the study underlined the role of personality pathology in in adolescence in the development of psychopathological disorders with NSSI and their high association with suicidal activity. The modification of various NSSI variants in the context of a coronavirus infection (COVID-19) pandemic may be due to the unique characteristics of the psychotraumatic factor. With the same strength of impact, the multidirectional influence on various personality types and comorbid psychopathological disorders in adolescence should be taken into account, when creating new models of therapeutic and socio-rehabilitation interventions for the adolescent contingent of patients.