Boris A. Levin

Phylogenetic relationships of the algae scraping cyprinid genus Capoeta (Teleostei: Cyprinidae).

We reconstructed the matrilineal phylogeny of Asian algae-eating fishes of the genus Capoeta based on complete mitochondrial gene for cytochrome b sequences obtained from 20 species sampled from the majority of the range and 44 species of closely related barbs of the genera Barbus s. str. and Luciobarbus. The results of this study show that Capoeta forms a strongly supported monophyletic subclade nested within the Luciobarbus clade, suggesting that specialized scraping morphology appeared once in the evolutionary history of the genus. We detected three main groups of Capoeta: the Mesopotamian group, which includes three species from the Tigris-Euphrates system and adjacent water bodies, the Anatolian-Iranian group, which has the most diversified structure and encompasses many species distributed throughout Anatolian and Iranian inland waters, and the Aralo-Caspian group, which consists of species distributed in basins of the Caspian and Aral Seas, including many dead-end rivers in Central Asia and Northern Iran. The most probable origination pathway of the genus Capoeta is hypothesized to occur as a result of allopolyploidization. The origin of Capoeta was found around the Langhian-Serravallian boundary according to our molecular clock. The diversification within the genus occurred along Middle Miocene-Late Pliocene periods.

Molecular phylogeny of the cyprinid tribe Labeonini (Teleostei: Cypriniformes)

The cyprinid tribe Labeonini (sensuRainboth, 1991) is a large group of freshwater fishes containing around 40 genera and 400 species. They are characterized by an amazing diversity of modifications to their lips and associated structures. In this study, a total of 34 genera and 142 species of putative members of this tribe, which represent most of the generic diversity and more than one third of the species diversity of the group, were sampled and sequenced for four nuclear genes and five mitochondrial genes (totaling 9465bp). Phylogenetic relationships and subdivision of this tribe were investigated and the placement and status of most genera are discussed. Partitioned maximum likelihood analyses were performed based on the nuclear dataset, mitochondrial dataset, combined dataset, and the dataset for each nuclear gene. Inclusion of the genera Paracrossochilus, Barbichthys, Thynnichthys, and Linichthys in the Labeonini was either confirmed or proposed for the first time. None of the genera Labeo, Garra, Bangana, Cirrhinus, and Crossocheilus are monophyletic. Taxonomic revisions of some genera were made: the generic names Gymnostomus Heckel, 1843, Ageneiogarra Garman, 1912 and Gonorhynchus McClelland, 1839 were revalidated; Akrokolioplax Zhang and Kottelat, 2006 becomes a junior synonym of Gonorhynchus; the species Osteochilus nashii was found to be a member of the barbin genus Osteochilichthys. Five historical hypotheses on the classification of the Labeonini were tested and rejected. We proposed to subdivide the tribe, which is strongly supported as monophyletic, into four subtribes: Labeoina, Garraina, Osteochilina, and Semilabeoina. The taxa included in each subtribe were listed and those taxa that need taxonomic revision were discussed.

New Evidence of Homoplasy Within the African Genus Varicorhinus (Cyprinidae): An Independent Origin of Specialized Scraping Forms in the Adjacent Drainage Systems of Ethiopia Inferred from mtDNA Analysis

Interrelationships of the two specialized scraping periphyton-feeders, Varicorhinus beso and V. jubae, and some large African barbs, Labeobarbus spp., inhabiting three main regions of Ethiopia (theWestern and Eastern Plateaus, and the Rift Valley separating them) were investigated using the sequence analysis of a fragment (609 base pairs) of the mtDNA control region. The two scraping forms in question appeared to be phylogenetically distant: V. beso had branched off before the main radiation of the Ethiopian Labeobarbus took place, whereas V. jubae is a sister group of the Labeobarbus gananensis complex sympatrically occurring with it in the south of the Eastern Plateau. For geographical reasons, among the congeneric species, V. jubae could be considered as the most closely related to V. beso, the type species of the genus, but judging from the available data this genus seems to be monotypic, while jubae should be classified as a member of Labeobarbus.

Two complete mitochondrial genomes of extinct form of the Sevan trout Salmo ischchan danilewskii

Abstract The mitochondrial genomes from two individuals of the extinct subspecies of the Sevan trout Salmo ischchan danilewskii are published in this paper. The mitochondrial DNA (mtDNA) is 16,665 base pairs (bp) in length and contained 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. The overall base composition of the genome in descending order was 27.9% of A, 29.4% of C, 16.7% of G, and 26.0% of T without a significant AT bias of 53.9%.

Pleiotropic effect of thyroid hormones on gene expression in fish as exemplified from the blue bream Ballerus ballerus (Cyprinidae): Results of transcriptomic analysis

A pronounced pleiotropic effect of thyroid hormones on the regulation of gene expression in fish in postembryogenesis was demonstrated for the first time using larvae and juveniles of the blue bream Ballerus ballerus as an example. Genome-wide transcriptome sequencing (RNA-seq) identified 1212 differentially expressed genes in the brain and liver of fish kept in triiodothyronine solution (0.25 ng/mL). Our data show that the regulation of gene expression by thyroid hormones is widespread in nature: it involves not only the structural genes but also the regulatory genes. A significant number of genes under the control of thyroid hormones are involved in the determination of morphological traits.

Sequencing of two mitochondrial genomes of endangered form of the Sevan trout Salmo ischchan aestivalis

Abstract The two complete mitochondrial genomes of endangered form of the Sevan trout Salmo ischchan aestivalis are published in this paper. The mitochondrial DNA (mtDNA) is 16,677 base pairs (bp) in length and contained 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. The overall base composition of the genome in descending order was 29.4% – C, 27.9% – A, 26.0% – T, 16.7% – G, without a significant AT bias of 53.9%.

Threatened fishes of the world : Barbus goktschaicus Kessler, 1877 (Cyprinidae)

(Armenian). Conservation status: Highly endangered species, close to extinction (Red Data Book of Armenia 1987). Identification: D III-IV/7–8, A III/5, LL 55–72, vertebrae 42–45 (Bogutskaya 2003). Last unbranched ray of the dorsal fin is ossified but weak with feebly developed serration disappearing in the largest specimens. Mouth inferior with thick lips. The body and the fins dotted with black. Karyotype: 2n = 100, including 24 metaor submetacentrics and 76 acrocentrics, NF = 124 (Krysanov 1999). Distribution: Endemic to lake Sevan and its tributaries (Armenia). Lacustrine form occurs at northern and north-west shore of lake. Riverine–lacustrine form inhabits the lake and the rivers: Vardenis, Makenis, Argitchi, Dzyknaget, Tsakkar (Dadikyan 1986). Riverine form dwells in the rivers: Dzyknaget, Masrik and Argitchi, but it is very rare in the first and the second rivers. The Argitchi population inhabits upper stream of river and being isolated from riverine and riverine–lacustrine populations by waterfall. Abundance: Formerly a common fish species of lake Sevan basin (there were only two other indigenous species: Salmo ischchan and Capoeta capoeta sevangi), but now less abundant than any of introduced species (Coregonus lavaretus and Carassius auratus). Habitat and ecology: The species is represented by different forms (Tchikova 1955): lacustrine (in the lake only, maximum size 30 cm and 500 g), riverine–lacustrine (in the lake, migrating into the rivers for breeding) and riverine (in streams only, maximum size 19 cm and 110 g). The main food items in the lake are species of the genus Gammarus and the Trichopteridae larvae. Reproduction: Spawning both in the lake (lacustrine form) and in some of its tributaries (riverine–lacustrine and riverine forms) from the late May to mid-August. Most females produce two portions of eggs with an interval of 12–15 days. Spawning occurs at 13.2–20.0 C in the lake and at 14.2–17.7 C in tributaries. Eggs are polyplasmatic, their shells are B. A. Levin (&) Severtsov Institute of Ecology and Evolution, IEE RAS, Leninsky prospekt, 33, 119071 Moscow, Russia e-mail: borislyovin@sevin.ru

Heterochronic development of lateral plates in the three-spined stickleback induced by thyroid hormone level alterations

The three-spined stickleback Gasterosteus aculeatus is an important model for studying microevolution and parallel adaptation to freshwater environments. Marine and freshwater forms differ markedly in their phenotype, especially in the number of lateral plates, which are serially repeated elements of the exoskeleton. In fishes, thyroid hormones are involved in adaptation to salinity, as well as the developmental regulation of serially repeated elements. To study how thyroid hormones influence lateral plate development, we manipulated levels of triiodothyronine and thiourea during early ontogeny in a marine and freshwater population with complete and low plate phenotypes, respectively. The development of lateral plates along the body and keel was heterochronic among experimental groups. Fish with a low dosage of exogenous triiodothyronine and those treated with thiourea exhibited retarded development of bony plates compared to both control fish and those treated with higher a triiodothyronine dosage. Several triiodothyronine-treated individuals of the marine form expressed the partial lateral plate phenotype. Some individuals with delayed development of lateral plates manifested 1–2 extra bony plates located above the main row of lateral plates.

DNA barcoding of the fishes of the genus Alburnoides (Actinopterygii, Cyprinidae) from Caucasus

Abstract Spirlins of the genus Alburnoides are widespread fishes, which taxonomy has been rapidly developing in recent years. Mitochondrial cytochrome c oxidase subunit I (COI) was used as DNA barcode marker to create a reference dataset of Caucasian Alburnoides and to test its barcoding efficiency. All four previously known Caucasian species of Alburnoides were confirmed as valid species with high genetic distances to sister species as well confirmed as Caucasian endemics. Alburnoides samiii, previously known from Sefidroud basin (Iran), was discovered in Transcaucasia. The accuracy of species identification of Ponto-Caspian Alburnoides by DNA barcodes was 100%. In addition, one potentially new species within A. gmelini was revealed. Despite the limited ability of COI to infer phylogenetic relationships, study provided evidence that Ponto-Caspian lineage of Alburnoides includes significantly larger number of species from Caspian Sea basin and inland basins of Central Asia.

A century in synonymy: molecular and morphological evidence for the revalidation of Glyptosternon osсhanini (Herzenstein, 1889) (Actinopterygii: Sisoridae)

Exostoma oschanini, presently treated as a junior synonym of Glyptosternon reticulatum, is revalidated within Glyptosternon based on a phylogenetic analysis of the CO1 gene and morphological characters. Glyptosternon oschanini is known to occur in tributaries of the Syr Darya River in Uzbekistan and Kyrgyzstan and may also occur in the Amu Darya River drainage. A morphological diagnosis and description are provided for G. oschanini. Exostoma gracile is a junior synonym of G. oschanini rather than of G. reticulatum.