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This study presents new data on the population-genetic polymorphism, phylogeny, and phylogeography of two vicariant species belonging to the Daphnia longispina s.lat. complex (Crustacea: Cladocera) in northern Eurasia, D. longispina s.str. and D. dentifera. Based on the variability of the fragments of noncoding 12S rRNA and the protein coding ND2 genes of mitochondrial DNA, the demographic processes that took place in populations of this vast region have been reconstructed. The previously suggested hypothesis about the different demographic history of the Siberian and European D. longispina s.str. clades has not been confirmed, since we first revealed a deep mitochondrial divergence within the Siberian clade. Moreover, a new divergent D. longispina s.str. lineage in Siberia has been identified. Nevertheless, the phylogeographic patterns of D. longispina s.str. and D. dentifera in northern Eurasia confirm the earlier conclusion that repeated, combined effects on their populations of dispersion and vicariate events occurred in different phases of the Pleistocene. [ABSTRACT FROM AUTHOR]

The first data on the population genetic structure of the Daphnia cristata Sars, 1862 and D. longiremis Sars, 1862 species (Anomopoda: Daphniidae) from the water bodies of Northern Eurasia are presented. The variability of the fragment of the 12S gene of the mtDNA for these taxa belonging to subgenus Daphnia (Daphnia) O.F. Müller, 1776 (Crustacea: Cladocera) in this region is studied, and a phylogenetic analysis performed. The genealogical relationships between haplotypes of the Daphnia cristata and D. longiremis species and their geographical distribution are shown. Our new data allow us to suggest a recent rapid spatial expansion for D. cristata during the Late Pleistocene and Early–Middle Holocene periods. According to the results of the study, the distribution of D. cristata and D. longiremis species are separated in the latitudinal direction with the zone of their contact in Central Yakutia. Our results provide convincing evidence for the influence of the Ice Ages and interglacials on the formation of modern genetic diversity and the phylogeographic structure of D. cristata and D. longiremis. [ABSTRACT FROM AUTHOR]

The results of morphological and genetic analysis of populations/forms/species of the pidschian-like whitefishes from the middle and lower streams of the Lena River and adjacent rivers are presented. There are good grounds to believe that despite considerable heterogeneity of whitefishes in Siberia, a small number of stable forms/species live in the waterbodies of the Siberian Arctic. These are the East Siberian whitefish (C. lavaretus pidschian n. brachymystax), glacial—plain whitefish (C. lavaretus pidschian n. glacialis) and Yukagir whitefish (C. lavaretus pidschian n. jucagiricus), as well as their hybrid populations. The glacial—plain whitefish and its derivatives differ from the East Siberian whitefish in plastic traits but they are identical in meristic ones. Molecular genetic studies showed that, in most cases, glacial—plain whitefish formed vast loosely connected haplotype networks, which corresponded to the long-term population existence in favorable conditions. Haplotypes of the East Siberian whitefish are closely related to the haplotypes of whitefish forms/species from the waterbodies of Southern Siberia, characterized by radial structure of median-joining network. Such network structure indicates a recent decline in the East Siberian whitefish numbers with subsequent expansion, which is directly associated with the Quaternary glaciation events. [ABSTRACT FROM AUTHOR]

The results from morphogenetic analysis of the whitefish populations from the middle stream of the Lena River and sympatric whitefish forms/species from the Baunt lake system are presented. The data showed that the lakes were inhabited by up to eight whitefish forms/species with relatively high degree of differentiation. The Dorong, Baunt, and Bolshye Kapylyushi lakes were found to be inhabited by sympatric whitefishes, similar in the number of gill rakers, but different in the perforated lateral line scale numbers. In addition, in Lake Baunt, endemic cisco-like densely rakered whitefish was found. Analysis of the mtDNA ND1 gene variation in different forms, including the whitefish populations from the middle stream of the Lena River, showed that the whitefish haplotypes from the Baunt lake system were strongly mixed and were based on several well-defined phylogenetic lineages. The cisco-like whitefish is of more ancient origin than other species of the pidschian-like whitefishes of the genus Coregonus. [ABSTRACT FROM AUTHOR]

Data on the species diversity, morphological variability, genetic structure, phylogeny, and phylogeography of the D. longispina s. l. group from water bodies of southern Siberia are summarized. The integrated approach involves traditional morphological studies, an analysis of body shape variability using geometric morphometrics, and study of the genetic variability based on mitochondrial (12S, 16S, ND2) and nuclear (ITS2) markers. This approach allows us to identify several forms/species within the genus Daphnia that are new and endemic to the fauna of Russia, to describe some distinctive features of their morphology, to reconstruct phylogenetic relationships within the D. longispina s. l. group, and to elucidate the distribution ranges of species, both common and rare. The study of the variability of mitochondrial DNA genes provided the opportunity to propose and substantiate the hypothesis that various forms/species of this cladoceran group could have passed through different evolutionary scenarios across the territory of northern Eurasia. [ABSTRACT FROM AUTHOR]

The results of morphogenetic analysis of sympatric forms/species of the Coregonus lavaretus pidschian (Coregonus pidschian) complex from the Olenek River basin are presented. It was demonstrated that the Olenek River basin was inhabited by three distant forms of whitefishes. Two of these forms, C. lavaretus pidschian n. brachymystax and C. lavaretus pidschian n. glacialis, were confined to the estuary, while the third form was found in the middle course of the river. It was demonstrated that all forms/species had similar numbers of gill rakers and perforated scales in the lateral line, while they were different in size and appearance. Analysis of the mtDNA ND1 gene sequence variation showed that these whitefishes belonged to phylogroups previously identified in the water bodies of the Taimyr Peninsula. The new whitefish form from the middle course of the Olenek River has the same mtDNA as glacial-plain whitefish, and according to allozyme analysis, it belongs to the group of East Siberian whitefishes, which indicates the hybrid nature of this form. [ABSTRACT FROM AUTHOR]

This work presents the results of morphological and genetic analyses of the sympatric forms/species of whitefishes of the Coregonus lavaretus pidschian (Coregonus pidschian) complex from Lake Kutaramakan of the Khantaisk drainage system (Taymyr Peninsula). It is found that the studied whitefish forms/species do not differ in the number of gill rakers on the first branchial arch, but are well distinguished by the number of perforated lateral line scales, most morphometric characters, and biological features. Analysis of variability of the mitochondrial ND1 gene shows that whitefishes from Lake Kutaramakan belong to two different phylogenetic lineages which were earlier found in water bodies of the Taymyr Peninsula, the Ob, Yenisei, and Anabar rivers. It is shown that some whitefish haplotypes belong to pidschian-like whitefish from the Ob River basin and other haplotypes belong to glacial-plain whitefish C. lavaretus pidschian natio glacialis (C. lavaretus pidschianglacialis). Unlike whitefishes from the Anabar River, where such forms are strongly differentiated, there is considerable hybridization between the forms in Lake Kutaramakan. [ABSTRACT FROM AUTHOR]

Cladocerans of the genus Daphnia O.F. Müller (Crustacea: Cladocera) are typical members of different types of water bodies and are used as model organisms in various biological disciplines. Within the genus, a considerable number of closely related and cryptic species are noted, the identification of which by morphological traits often causes difficulties. In the present study, species identification in the Daphnia longispina complex, namely, D. longispina O.F. Müller, D. hyalina Leydig, D. umbra Taylor, Hebert et Colbourne, and D. cf. longispina, was performed using data on the predicted secondary structure of the second internal transcribed spacer (ITS2) of the nuclear rDNA. Phylogenetic analysis carried out using the Profile Neighbor-Joining algorithm and the analysis of compensatory base changes supported the species status of D. hyalina and D. cf. longispina. It was demonstrated that the data on the ITS2 secondary structure can be used to resolve complex taxonomic problems in the study of cladocerans in general and the species complexes in particular. [ABSTRACT FROM AUTHOR]

Data on the morphology, biology, and genetics of two ecological forms of pidschian-like whitefishes of the genus Coregonus, corresponding to the descriptions of East Siberian whitefish, C. lavaretus pidschian natio brachymystax, and glacial-plain whitefish, C. lavaretus pidschian natio glacialis, from the Anabar River of western Sakha (Yakutia) Republic (Russia), are presented. According to meristic characters, no differences are found between these ecological forms, while on the basis of plastic traits and occupied ecological niches these whitefishes differ substantially. We demonstrate that, on the basis of the sequences of the ND1 gene of the mtDNA, the East Siberian whitefishes are only slightly different from the whitefishes from the lower Ob River and Lake Teletskoye (Upper the Ob River basin), and probably have a common origin with them. Glacial-plain whitefishes from the Anabar River have a common origin with whitefishes from the water bodies of the Taimyr Peninsula and represent a complex of forms/species. [ABSTRACT FROM AUTHOR]

The purpose of this work is to study the interaction of morphologically similar forms of pidschianlike whitefishes of the Coregonus lavaretus complex inhabiting a limited area in the riverine-lacustrine system of the Bolshoy Abakan River basin. Sequences of the 16S-ND1 fragment of the mitochondrial DNA and the first intermediate transcribed spacer ITS1 of the nuclear DNA are determined. It is shown that whitefish populations differ based on the gill raker numbers and the complex of plastic traits. Analysis of the 16S-ND1 fragment of the mtDNA revealed several divergent lineages, which is confirmed by the study of the ITS1 of the nDNA. As a result, it is shown that the riverine-lacustrine system is inhabited by two genetically divergent whitefish populations. The results of the study support the hypothesis of multiple hybridization between slightly differentiated forms/populations of whitefishes during the postglacial period. As a result of the studies carried out, the hypothesis about the origin and possible ways of migration of some phylogenetic lineages of whitefishes in the water bodies of the Yenisei River basin is proposed. [ABSTRACT FROM AUTHOR]

Comparative study on morphological variability of the polymorphic species Daphnia galeata Sars from the lakes of the Todzha Depression was carried out. The purpose of this study was to estimate the population variability and adaptive opportunities of this species. It was revealed, that almost all samples from the populations were reliably differed from each other based on body size. We did not find any significant differences based on the number of paired spines on postabdomen and fecundity between most of the populations. All individuals were characterized by pointed helmet, and helmet length varied markedly among the populations across the lakes. Moreover, it was found a high morphological variability of helmet length and shape and some traits of head for D. galeata. In spite of the fact that helmet length of D. galeata was extremely variable, the samples from the different lakes organized an overlapping cloud in the space of the second and third principal component axes. We assume that the morphological variation of D. galeata from the lakes of the Todzha Depression belongs to populational and depends on the environmental conditions. [ABSTRACT FROM AUTHOR]