Biological features of Low Amur grayling Thymallus tugarinae (Salmoniformes: Thymallidae): 2. Growth

We present the results of analysis of the group growth of the Low Amur grayling Thymallus tugarinae from 18 rivers of the Low Amur basin, tributaries of the Bureya and Ussuri rivers. We made use of the published data on the fishes of Sakhalin Island. The dwarf and fast-growing forms are not revealed among the investigated groups of this species. The parameters of growth of the Low Amur grayling in the investigated rivers are different, which is determined by the different conditions of feeding migration connected with the geographical location of the streams, their hydrological features, density of populations, etc. The anthropogenic factor influence is essential. Growth rate of T. tugarinae is lower compared with the other Amur species of graylings.     

Seismosensory system of the Lower Amur rayling <Emphasis Type="Italic">Thymallus tugarinae</Emphasis> (Thymallidae) from the Anyui River

Data on specific features of the seismosensory system of the Lower Amur grayling Thymallus tugarinae from the Anyui River (basin of the Lower Amur) are provided. According to the number of openings in canals of the seismosensory system, individuals from the middle course significantly differ from graylings from the lower course in greater values of interpopulation diversity and fluctuating asymmetry. According to the number of pores of canals of the seismosensory system, the Lower Amur grayling differs from the East Siberian T. arcticus pallasi, Kamchatka T. a. mertensii, and Alaska T. a. signifer graylings.     

On the diversity and taxonomic status of graylings (Thymallus Thymallidae) from the Lena River

Two forms of graylings were distinguished in the Lena River, which differ in body coloration, the shape and pattern of the dorsal fin, and biological characteristics. With respect to these traits, the forms are divided between the upper and lower Lena. The first inhabits most of the basin, from the upper courses to the lower reaches, whereas the second inhabits the Lena delta and the adjacent arctic rivers and their tributaries. Comparative analysis of meristic traits revealed their low appropriateness for diagnosing Lena lineages as well as grayling populations inhabiting other northern rivers of Siberia. The body and fin coloration in the upper Lena form significantly differ from that found in forms and subspecies of graylings from the basins of the other rivers in the ranges of Eastern Siberian, Kamchatka, and Alaska. The lower Lena form should be classified with the Eastern Siberian subspecies T. arcticus pallasii and is closer to the populations of graylings from the rivers Anabar and Yana, and the rivers of the Chukot Peninsula and Alaska, and the upper courses of the Missouri. These results are supported by analysis of the mitochondrial DNA of graylings throughout the Paleoarctic. Further studies of these lineages and phylogenetic relationships between Arctic lineages are necessary for the final determination of the taxonomic status of the upper Lena form.     

A comparative analysis of two Amur grayling species from the <Emphasis Type="Italic">Thymallus</Emphasis> Genus (Salmoniformes; Thymallidae) according to a number of osteological and morphological features in their zone of sympatry

The results of the comparison of the Lower Amur grayling Thymallus tugarinae and the yellowspotted grayling T. flavomaculatus that were collected in the zone of their sympatry in the middle reaches of the Anuy River (the Lower Amur basin) for a number of osteological and morphological features are provided. The work was based on the analysis of X-ray images and a number of plastic features. Considerable differences were detected between the two species in the numbers of the bone elements of the axial skeleton. The differences in the number and topography of certain bone elements correlate with the morphological features of these species. The comparison results for certain features do not correspond with the literature data.     

Graylings of Baikal Lake basin (Thymallus, Thymallidae): Diversity of forms and their taxonomic status

The morphological characters, molecular-genetic features, and patterns of the dorsal fin in different subspecies and forms of Arctic grayling Thymallus arcticus populating Lake Baikal and its tributaries, Irkutsk Reservoir, and Lake Khubsugul have been studied. Three groups are discernable. The first includes the white and black Baikal graylings T. a. baicalensis, as well as the western Siberian T. a. arcticus; the second group is represented by the Kosogol grayling T. a. nigrescens, and the third is composed of T. arcticus ssp. from the Yakchii lakes (the Verkhnyaya Angara basin) with a phenotype close to graylings populating the upper reaches of the Lena River. All of them are distinguished by some morphological characters, elements of the dorsal fin pattern, and by body coloration. The populations of black Baikal graylings are genetically uniform, and their distinctions from white Baikal graylings are insignificant, which agrees with the absence of a considerable divergence of these forms by a complex of meristic characters. It is assumed that in the black and white Baikal graylings the exchange by genetic information has either ceased quite recently, or persists, although, insignificantly. Some genetic remoteness of the west Siberian grayling from Irkutsk Reservoir and Nizhnyaya Tunguska, closely related to the Baikal grayling, is recorded. The formation of the Khubsugul subspecies is possibly a result of the contact of grayling populations during the rearrangements of the river system in the last glaciation period in the upper reaches of Yenisei and Selenga in Mongolia. The habitation in the Baikal system of the Upper Lena graylings indicates a connection between the Lena and Baikal basins in the past. The results of a multivariate analysis of meristic characters and the sequences of mitochondrial DNA confirm the conclusion made by Svetovidov (1931, 1936), concerning the absence of grounds to assign a species status to the Baikal forms.     

Biological and morphological characteristic of the Arctic grayling Thymallus arcticus (Thymallidae) from Alpine Lakes of the basin of the upper reaches of the Angara River

Specific morphological and biological features of the populations of the Arctic grayling Thymallus arcticus from lakes Urunge Nur, Mongosha, Sadaiskoe, and Gusinoe situated in the Upper Sayan Mountains in the sources of the Oka and Kitoi rivers (the basin of the upper reaches of Angara) that have been not studied previously are considered. The results of the multivariate analysis indicated the uniformity of all samples by 12 meristic characters. Graylings of the studied lakes are similar to graylings from the Angara and Nizhnyaya Tunguska rivers and the Irkutsk Reservoir, as well as to the Baikal grayling T. a. baicalensis in body coloration and pattern of the dorsal fin. The samples studied and T. a. baicalensis considerably differ in the above characters from populations inhabiting the basin of the upper reaches of the Ob that belong to the nominative subspecies T. a. arcticus. The differences established between the Angara-Yenisei and the Upper Ob graylings give grounds to doubt the justification of including them into one taxon, T. a. arcticus. The same is evidenced by the results of molecular-genetic studies of graylings from the Palearctic (Froufe et al., 2005). The data obtained indicate the necessity of ascertaining the boundaries of the ranges of different forms of graylings in the Angara-Yenisei and Ob basins and of the revision of their taxonomic status. Populations inhabiting the Angara and Yenisei rivers, except their sources and the section of the lower reaches, should be assigned to the Baikal subspecies, T. a. baicalensis. Graylings from different lakes in the upper reaches of Oka and Kitoi differ in their linear-weight indices. The indices of growth are highest where they occupy a dominant position. Their food in the summer consists mainly of the larval and imaginal stages of amphibiotic and aerial-terrestrial insects. Only in Lake Urunge Nur do graylings of elder age groups use fish of other species for food. The extreme conditions of habitation of the grayling in Lake Gol’tsovoe are the cause of food deficiency, which determines its dwarfism.     

Biological specific features of the Lower Amur grayling Thymallus tugarinae (Salmoniformes: Thymallidae): 1. Age composition

We consider age composition of samples of the Lower Amur grayling Thymallus tugarinae inhabiting water bodies of the lower and middle course of the Amur and several rivers of the northwestern part of Sakhalin Island and the southern coast of the Sea of Okhotsk. Age composition of the Lower Amur grayling from the studied samples is not similar because of several reasons. In rivers of the Amur basin, the species has a maximal age of 6+.     

Grayling (Thymallinae) phylogeny within salmonids: complete mitochondrial DNA sequences of Thymallus arcticus and Thymallus thymallus

The phylogenetic relationships among the three subfamilies (Salmoninae, Coregoninae and Thymallinae) in the Salmonidae have not been addressed extensively at the molecular level. In this study, the whole mitochondrial genomes of two Thymallinae species, Thymallus arcticus and Thymallus thymallus were sequenced, and the published mitochondrial genome sequences of other salmonids were used for Bayesian and maximum‐likelihood phylogenetic analyses. These results support an ancestral Coregoninae, branching within the Salmonidae, with Thymallinae as the sister group to Salmoninae.     

A new subspecies of the amur grayling Thymallus grubii flavomaculatus ssp. nova (Thymallidae)

A new subspecies of the Amur grayling is described, the yellow-spotted grayling Thymallus grubii flavomaculatus ssp. n. populating the upper reaches of large tributaries of the Lower Amur basin and some rivers flowing to the Tatar Strait, the Sea of Okhotsk, and the Sea of Japan. From nominative subspecies T. g. grubii populating the basin in the upper reaches of the Amur and from other representatives of the genus Thymallus, this subspecies differs in the dorsal fin pattern whose principal trait is a yellow spot on the last two-five interray membranes, in the body coloration, and in some morphological characters. The yellow-spotted grayling in the upper reaches of tributaries sympatrically coexists with the Lower Amur grayling Thymallus sp. No specimens with intermediate characters are found. The sympatric forms spawn at different times, thus being isolated reproductively. Isolation of the yellow-spotted grayling as a subspecies of the Amur grayling T. grubii is confirmed by the results of molecular-genetic investigations.     

New species of grayling <Emphasis Type="Italic">Thymallus tugarinae</Emphasis> sp. nova (Thymallidae) from the Amur River Basin

Data on a new species, low Amur grayling Thymallus tugarinae sp. nova, inhabiting tributaries of the lower and middle current of the Amur River, are presented. This species has been earlier equated with the Amur grayling T. grubii, described by Dybowski (1869) from the rivers Onon and Ingoda (the Upper Amur Basin). The new species differs from other representatives of the genus in the body coloration, the pattern on the upper fin, and certain morphological characters. On most of the Amur Basin, the grayling from the Lower Amur is sympatric with T. grubii and in its tributary Bureya River, also with the Bureya grayling T. burejensis. Individuals with intermediate traits are unknown, pointing to reproductive isolation. These data are supported by the results of molecular-genetic analysis (Froufe et al., 2003, 2005; Knizhin et al., 2004).     

Finding a new form of the grayling Thymallus arcticus (thymallidae) in the basin of lake baikal

A dwarf form of the Arctic grayling Thymallus arcticus, inhabiting a group of small lakes at the origin of the Yakchii stream, which flows into the Verkhnyaya Angara River (basin of Lake Baikal), has been found in the northeastern watershed of the Baikal and Lena basins. The form is similar to upper Lena populations in body coloration and the pattern of dorsal fin. Our comparison by meristic characters indicated that the grayling of the Yakchii Lakes is more similar to the fish from Kutima River (basin of the upper courses of the Lena River) than to the black Baikal grayling T. arcticus baicalensis. The presence in Lake Baikal of a population similar to upper Lena graylings may have three causes: (1) possible drainage from Baikal to the pra-Lena via ancient valleys of the Barguzin and the Upper Angara; (2) appearance of transit zones as a result of glacial or tectonic events during the periods of watershed development between the Baikal and Lena basins; (3) the upper Lena grayling could be an endemic of the Baikal basin which was replaced by graylings penetrating from the Yenisei basin and remained in the form of relic populations in the upper courses of certain tributaries of the northern and northeastern parts of Lake Baikal.     

Molecular phylogenetic status of the Bulgarian marbled polecat (Vormela peregusna,Mustelidae, Carnivora), revealed by Y chromosomal genes and mitochondrial DNA sequences

In this study, we investigated molecular phylogenetic status of the marbled polecat (Vormela peregusna) from Bulgaria, using sequences of two Y-chromosomal genes (SRY and ZFY). The phylogenetic tree inferred using combined sequences of both genes indicated that the marbled polecat was split from genera Lutra, Neovison and Mustela after genus Martes was diverged in family Mustelidae. In addition, we analyzed molecular phylogeography of the Bulgarian population of the marbled polecat, using cytochrome b and control region sequences of mitochondrial DNA (mtDNA). The phylogenetic tree of cytochrome b indicated that the haplotypes of the Bulgarian population comprised two haplogroups, which were the most ancestral clades. Additionally, the control region phylogeny showed that the haplotypes of Bulgaria formed two haplogroups: one was the most ancestral clade, and the other was the derivative clade. One individual with the most ancestral cytochrome b clade had a control region haplotype of the derivative clade. Thus, this study revealed that the most ancestral lineages of the marbled polecat are included in the population of Bulgaria. The Bulgarian population could be a remnant lineage from a basal for the species, which in Pleistocene occupied a relatively large area related to the Balkan-Caucasian.     

Multiple species of grayling (Thymallus sp.) found in sympatry in a remote tributary of the Amur River

Large-scale phenotypic and genetic studies of the salmonid genus Thymallus (grayling) in the Palaearctic suggest that most major phylogeographic lineages represent good biological species. Evaluating such a premise in areas involved in palaeo-hydrological dynamics where multiple species are found in sympatry should serve to assess the level of reproductive isolation, the traditional sine qua non of species recognition. Molecular sequence (mtDNA) and microsatellite (nDNA, seven loci) analysis of grayling in the upper Bureya River watershed support the occurrence of three distinctive species of grayling living in sympatry in this large oligotrophic tributary of the Amur River. One of these lineages is primarily found throughout the Lena River basin and is recognized as Baikal-Lena grayling Thymallus baicalolenensis; the second, the upper Amur grayling Thymallus grubii is found over large areas of the Amur catchment including the entire headwater region; and the third, the Bureya grayling Thymallus burejensis is endemic to the study area. A limited number of hybrids were identified, primarily between Baikal-Lena grayling T. baicalolenensis and Bureya grayling T. burejensis with little to no signs of introgression among non-hybrid individuals. Morphological distinctiveness among populations of these species living in sympatry was greater than between populations living in allopatry, suggesting character displacement. Divergence estimates among taxa range up to 6.2 MY, and allopatric origins for all three species’ is suggested. To our knowledge, this is the first data-based confirmation of three species of grayling living in sympatry.     

Molecular identification of Korean catfish (Siluriformes) based on two genetic markers

Eleven species of catfish (Siluriformes) found in Korean freshwater are economically important resources and include five endemic species. However, there are no studies on phylogenetic analysis of all catfish species in Korea at a molecular level. The species-level analysis of catfish species is usually carried out through morphological characters and controversial due to phenotypic variation. In this study, the partial sequences of 16S rRNA and cytochrome b mitochondrial genes were analyzed for species identification and phylogenetic relationships among 11 species of catfish from 10 different rivers in Korea. The nucleotide sequences of 16S rRNA and cytochrome b consisted of 587 and 441 nucleotide base pairs, respectively. Sequence analysis of both genes revealed that the 11 species fell into three distinct groups, which were genetically distinct from each other and exhibited identical phylogenetic resolution. Sequence divergences between congeneric species averaged 1.78% and 7.39% for 16S rRNA and cytochrome b, respectively. The phylogenetic relationships forming well-differentiated clades in the NJ, ML and BI trees were identical for both fragments. This research demonstrates that partial sequences of both the genes can efficiently identify the 11 species of catfish in Korea, indicating the usefulness of mtDNA-based approach in species identification.     

Molecular diversity and phylogeography of Andricus curtisii (Hymenoptera,Cynipidae) in Turkey

A 433-bp fragment of the mitochondrial cytochrome b gene and the entire nuclear ITS2 region were sequenced in an oak gall wasp species, Andricus curtisii, which represents 21 populations across its range in Turkey. Forty cytochrome b haplotypes and 63 ITS2 alleles were discovered among the 161 individuals studied. Remarkable genetic variation was detected in the species, with an average haplotype diversity (h) of 0.72 and 0.76 and an average nucleotide diversity (π) of 0.06 and 0.01 for the cyt b gene and the ITS region, respectively. Most populations were genetically distinct, possessing unique cytochrome b haplotypes. Maximum likelihood and Bayesian phylogenetic analyses and application of the haplotype network to both datasets revealed that the most basally located haplotypes/alleles were from the eastern part of Turkey. The detection of older sequences in the phylogenetic trees of the easterly located populations implied an eastern origin of the species. The application of a conventional insect mitochondrial DNA clock to the dataset suggested a splitting of ingroup haplotypes from the outgroup lineages predating the Pleistocene epoch and the formation of two major haplogroups that coincided with the oscillation of the early Pleistocene glaciations.     

Genetic divergence and phylogenetic independence of Far Eastern species in subfamily Leuciscinae (Pisces: Cyprinidae) inferred from mitochondrial DNA analyses

Classification of freshwater fish in the subfamily Leuciscinae, Cyprinidae is hampered by complexity or lack of morphological diversity. In this study, analyses based on mtDNA sequences were undertaken to clarify phylogenetic relationships among Far Eastern, North American and European species in the Leuciscinae. Evolutionary rate in cytochrome b gene (Cyt-b) and D-loop sequences appear to be almost constant in Leuciscinae. The topology of phylogenetic trees generated by neighbor-joining (NJ) and maximum likelihood (ML) methods based on Cyt-b gene and D-loop sequences was similar. Five major clades, designated clades 1-5, and a minor clade were discriminated. Most of the Far Eastern, North American and European species were included in the major clades. Clade 1, comprised almost entirely of Far Eastern phoxinins, is monophyletic and greatly diverged from the other species of Leuciscinae. From the present phylogenetic relationships and the previous studies, we present the following hypotheses with respect to the evolutionary history of the Far Eastern phoxinins. The Far Eastern species should be classified into Far Eastern-specific genera, although ichthyologists have still insisted that the species should be included in the European genera. The Far Eastern clade 1 consists of two subclades, including genera Pseudaspius-Tribolodon and Far Eastern Phoxinus species. According to our phylogenetic analyses, Pseudaspius leptocephalus and Tribolodon species should be reclassified into the same genus. On the basis of evolutionary rate in Cyt-b gene in Cyprinidae, it is estimated that the Far Eastern lineage diverged approximately 10-14 million years ago (mya) from the common ancestor of Leuciscinae. It is deduced that speciation of the Far Eastern species occurred until approximately 4 mya, in relation to the formation of the Sea of Japan and the Japanese Islands.     

Molecular phylogeny and intraspecific structure of loaches (genera <Emphasis Type="Italic">Cobitis</Emphasis> and <Emphasis Type="Italic">Misgurnus</Emphasis>) from the Far East region of Russia and some conclusions on their systematics

Russian Far East loaches of the genera Cobitis and Misgurnus are among members of the family Cobitidae with poorly understood systematics. In this study we present phylogenetic hypotheses based on mitochondrial (cytochrome b) and nuclear (RAG-1) sequences. All analyses recovered comparable topological phylogenies, and all data sets supported the non-monophyly of the genera Cobitis and Misgurnus. Both genera are represented by multiple lineages that in some cases do not correspond to the species described. We found some phylogenetic incongruities for the genus Misgurnus (M. mohoity and M. anguillicaudatus) that are explained by ancient hybridization, as was suggested previously for M. anguillicaudatus. The revealed phylogenetic relationships suggest that Paramisgurnus should be treated as a synonym of Misgurnus and M. bipartitus as a synonym of M. mohoity. All analyses recovered C. choii as a member of the genus Cobitis, confirming previous taxonomic conclusions. Most of the molecular lineages found follow currently recognized taxa with some exceptions, such as M. anguillicaudatus and C. lutheri. Phylogenetic relationships recover several unrelated lineages of M. anguillicaudatus and suggest additional studies to solve current taxonomic uncertainty. We found that C. lutheri is a non-natural group that contains two unrelated lineages: specimens of C. lutheri from the Far East of Russia collected close to the type locality and a second lineage with specimens of C. lutheri from Korea, the identification of which must be revised. The study provides evidence of the presence of the Far East species M. nikolskyi in Sakhalin Island, but simultaneously shows conspicuous genetic distinctiveness between the island and the mainland populations.     

Host specificity of avian haemosporidian parasites is unrelated among sister lineages but shows phylogenetic signal across larger clades

Parasites can vary in the number of host species they infect, a trait known as “host specificity”. Here we quantify phylogenetic signal—the tendency for closely related species to resemble each other more than distantly related species—in host specificity of avian haemosporidian parasites (genera Plasmodium, Haemoproteus and Leucocytozoon) using data from MalAvi, the global avian haemosporidian database. We used the genetic data (479 base pairs of cytochrome b) that define parasite lineages to produce genus level phylogenies. Combining host specificity data with those phylogenies revealed significant levels of phylogenetic signal while controlling for sampling effects; phylogenetic signal was higher when the phylogenetic diversity of hosts was taken into account. We then tested for correlations in the host specificity of pairs of sister lineages. Correlations were generally close to zero for all three parasite genera. These results suggest that while the host specificity of parasite sister lineages differ, larger clades may be relatively specialised or generalised.     

Mitochondrial cytochrome b gene variation in brown bear (Ursus arctos Linnaeus, 1758) from southern part of Russian Far East

The genetic variability of brown bear Ursus arctos from the southern part of the Russian Far East was first examined based on the variations in the mitochondrial DNA cytochrome b sequence. The presence of two phylogenetic groups of haplotypes described previously for other parts of the species range was demonstrated. Part of the samples belonged to the haplotype group distributed across the whole range, while another part belonged to the rare group previously only reported for Japan and Alaska. These findings partially clarify the pattern of brown-bear colonization on the territory of the Russian Far East and Japan.     

Comparative analysis of oocyte growth in two forms of Baikal grayling <Emphasis Type="Italic">Thymallus baicalensis</Emphasis> (Thymallidae)

Size characteristics of oocytes of the elder generation of the end of previtollogenesis, as well as of the beginning and middle of the phase of cytoplasm vacuolization in two forms of Baikal grayling Thymallus baicalensis were studied. In each form, the dependence of oocyte parameter on the age and size of females is traced. During the studied phases of development—at the termination of the period of previtellogenesis and at the proper beginning of the period of vitellogenesis—oocytes of the white and black graylings have similar sizes; cytoplasm vacuolization in white grayling proceeds less actively. It was established that differences in the diameter of mature ovicells in the black and white Baikal graylings result from dissimilar rate of accumulation of trophic substances in the oocytes of the given forms of this species and are determined by differences in the rate of growth of oocytes during the formation in them of yolk inclusions.