volume 34

volume 34 part 2

Amur River; bivalve; Amuranodonta kijaensis; glochidia;
pp. 35 -

Information on distribution of protected freshwater bivalve Amuranodonta kijaensis (Bivalvia, Unionidae, Anodontinae) is being clarified. For the Amur Region, three new locations of the species are indicated: Yatsenkovo and Peresheechnoye lakes on the territory of the Khingan Nature Reserve and Zeya Reservoir at the Beregovoy settlement. First record of A. kijaensis near Chnyrrakh village (Nikolaevsky District, Khabarovsk Territory) confirms the presence of the species in the Lower Amur basin. Data on morphometric analysis of collected shells of adult mollusks is presented. Using scanning electron microscopy, morphology of glochidial shells with special focus on microsculpture of the outer valves structure is investigated.

Новые данные об охраняемом пресноводном двустворчатом моллюске Amuranodonta kijaensis Moskvicheva, 1973 (Unionidae, Anodontinae)
Саенко Е.М.; Балан И.В.; Гафицкая И.В.; Широкая А.А.;
North Pacific; Arctic; biogeography; phylogeny; integrative systematics; speciation;
pp. 49 -

We provide a morphological examination and a barcoding study to investigate the species identity and variation limits within the Cadlina laevis species complex. Our molecular analysis based on the COI marker revealed seven new clades in the North-West Pacific Cadlina diversity. The distances between these clades are low in some cases (2.08-7.51% overall), and the species delimitation tests gave controversial results (1, 2, 13, 14 groups, depending on the analysis method). This does not allow to conclusively classify this diversity as interspecific or intraspecific. Morphological analysis showed a significant similarity of all examined groups, with minor differences found in the morphology of the central tooth of the radula and the reproductive system. However, these variations fit into the morphological variability of the North Atlantic species Cadlina laevis s.str. and cannot serve as evidence of the isolation of these identified groups. The discovered diversity may represent both a complex of at least 11 very close and cryptic species with not well-established species boundaries, or be a part of a single amphiboreal species Cadlina laevis s.l. This indicates an extremely complex evolutionary history of Cadlina laevis species complex, making this group is an interesting model object for studying speciation in boreal and Arctic communities.

Пятьдесят оттенков белого: морфологическое и молекулярное разнообразие комплекса видов Cadlina laevis (Gastropoda: Nudibranchia) в северо-западной Пацифике
Екимова И.А.; Гришина Д.Ю.; Вальдес А.; Антохина Т.И.; Чичвархина О.В.; Щепетов Д.М.;
North-West Pacific; integrative systematics; biodiversity; phylogeny; biogeography; Mollusca; Gastropoda;
pp. 69 -

In this paper we investigate a collection of nudibranch molluscs from Sakhalin Is. by means of integrative taxonomy, including morphological analyses, and molecular data from the cytochrome c oxidase subunit I, 16S rRNA, Histone H3 and 28S rRNA markers. Material used in this study was collected during two independent research programs: the expedition of the R/V “Akademic Oparin” (Russia) to the Sea of Okhotsk, July 2019 at depths of 38–282 m, and the survey of Cape Crillon biodiversity in August 2023, at depths of 0.5–20 m. Our integrative results revealed clear cases of the unknown diversity within some groups of the nudibranch molluscs. Among the dorid nudibranchs, the new species Adalaria boussoleana sp. nov. is described and differs in morphological and molecular characters from other species of the genus. Also, among specimens of the genus Cadlina we have detected two genetically distinct groups, one is close to C. umiushi and another group likely represents a new species for science. Their morphology is similar to the diagnosis of C. umiushi and may represent a case of true cryptic diversity. Among the cladobranch molluscs our results revealed a new species of the genus Cuthonella described herein under the name Cuthonella anastasia sp. nov. Four species are recorded for Sakhalin Is. waters for the first time: Cadlina umiushi, Onchimira cavifera, Eubranchus rupium and E. alexeii. After this paper, the total nudibranch fauna of Sakhalin Is. includes 21 species. Although we have limited numbers of nudibranch species in Sakhalin waters due to low sampling effort, a comparison of the biogeographic affinities of species from different regions is consistent with the presence of a biogeographic boundary between northeastern and southwestern Sakhalin.

Голожаберные моллюски острова Сахалин, северо-западная часть Тихого океана: новые находки и описание двух новых видов
Екимова И.А.; Гришина Д.Ю.; Никитенко Е.Д.;
Irtysh River basin; range expansion; morphology; ecology; abundance; biomass;
pp. 93 -

Juvenile and subadult individuals of the Painter’s mussel Unio pictorum (Linnaeus, 1788) were recorded in dredge samples from the Om’ River in the Omsk City (southwestern part of Western Siberia). Information on the size-weight characteristics of U. pictorum from the site, its abundance and biomass are given. Possible consequences of the introduction of this neobiotic species into aquatic ecosystems of the Irtysh River basin are discussed.

Находка моллюска Unio pictorum (Linnaeus, 1758) (Bivalvia: Unionidae) в реке Омь (Западная Сибирь)
Андреева С.И.;