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1

Fishes of inland waters of the Phu Quoc Island, Gulf of Thailand, Vietnam: ichthyofauna structure and some remarks on the major evolutionary trends in its genesis

100%
Vasil'eva E. D., Vasil'ev V. P.
Acta Ichthyologica et Piscatoria
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2012
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tom 42
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nr 3
Background. The ichthyofauna of the Phu Quoc Island (Vietnam), situated in the Gulf of Thailand in the proximity of the coastline of Cambodia, has not been sufficiently studied. The isolation of the island combined with the knowledge on its geological history could yield conclusions on the evolutionary trends and speculations on how individual faunistic groups were formed. The aims of this study were to investigate the recent ichthyofauna of the Phu Quoc Island and to analyze the major evolutionary trends in its history by a comparison with recent faunas of the neighbouring mainland. Materials and Methods. A total of about 4000 fishes representing 97 different teleostean species were collected at 46 sampled sites in the Phu Quoc Island from 6 December 2011 to 12 January 2012 by using different kinds of sampling equipment and collection methods as well as through exploring different habitats. Verification of field species identification and further morphological studies were based on 1290 specimens. Results. The list of fishes collected in inland waters of the Phu Quoc Island includes 97 species representing 13 orders and 39 families of teleostean species. The majority of these species correspond to the main diagnostic characters of known valid taxa. Two species (Kryptopterus bicirrhis and Brachygobius doriae) demonstrate some differences from their previously recorded diagnostic features, and two cypriniform species significantly differ from their valid congeners and should be described as new taxa. Conclusion. The major trends in the history of the ichthyofauna of Phu Quoc Island were the elimination of true freshwater stenobiontic species and the progressive development of euryhaline and eurytropic species which replaced former species in seasonally variable biotopes of relatively small tropic island. These eurytropic species are characterized by rather wide morphometric variability and do not demonstrate significant differences in their diagnostic characters comparing the island- and the mainland populations. Two species evolved into separate new taxa during the about 10 000 year time interval of the fauna’ isolation are characterized by the only common feature—belonging to small short-lived species. As such they were more prone to faster evolutionary changes and the pace of the speciation process. The evolutionary process in fish of the Phu Quoc Island was characterized by weak founder effect and weakly pronounced disruptive selection—producing a low number of evolved species.
2

Karyological study in backcross hybrids between the sterlet, Acipenser ruthenus, and Kaluga, A. dauricus (Actinopterygii: Acipenseriformes: Acipenseridae): A. ruthenus x (A. ruthenus x A. dauricus) and A. dauricus x (A. ruthenus x A. dauricus)

81%
Vasil'ev V. P., Rachek E. I., Lebedeva E. B., Vasil'eva E. D.
Acta Ichthyologica et Piscatoria
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2014
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tom 44
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nr 4
Background. Acipenserid fishes may be divided into three groups in terms of their ploidy levels: 1) 120-chromosomes, 2) 250–270-chromosomes, and 3) about 370-chromosomes. The experimental crosses show that sturgeon species with the same ploidy often produce fertile hybrids, whereas the hybrids between species with different ploidy cannot reproduce because of female sterility or full sterility. To date, the only case of backcross hybrids obtained by hybridization of sturgeons with different ploidy is known: in these crosses, the sterlet, Acipenser ruthenus Linnaeus, 1758, with about 120 chromosomes and kaluga, Acipenser dauricus Georgi, 1775, with about 270 chromosomes were used as parental species; numerous progenies were obtained for females of both species and fertile hybrid males. The aims of this study were to determine the chromosome numbers in hybrid spermatozoa, involved in the production of viable backcross progenies, and to ascertain the chromosome numbers in backcrosses. Materials and Methods. The experiments for obtaining backcrosses were conducted in the Luchegorsk experimental station of the TINRO Centre in 2010. 16 one-year-old backcross hybrids sterlet × (sterlet × kaluga) and 14 one-year-old backcrosses kaluga × (sterlet × kaluga) were karyologically studied by using previously described method. From one to 23 metaphase plates were analyzed from every studied fish. Results. Average chromosome numbers in 14 backcross hybrids sterlet × (sterlet × kaluga) varied from 139 to 157. It means that hybrid males (sterlet × kaluga), participated in their origin, produced spermatozoa with 79–87 chromosomes. Two other backcrosses sterlet × (sterlet × kaluga) had about 178 and 184 chromosomes. Thus, they got 118–124 chromosomes from their fathers. Among backcrosses kaluga × (sterlet × kaluga), 11 specimens had 201–214 chromosomes, and three specimens: 219–223. It means that hybrid males, participating in their origin, should produce spermatozoa with 66–84 and 84–93 chromosomes, respectively. Conclusion. This study suggests non-random generation of chromosome sets in spermatozoa of fertile sterlet × kaluga hybrids. However, the mechanisms of meiosis, providing a non-random production of spermatozoa with similar numbers of chromosomes, are still unknown.
3

Further studies of mitochondrial genome variability in Ponto-Caspian Proterorhinus species (Actinopterygii: Perciformes: Gobiidae) and their taxonomic implications

81%
Sorokin P. A., Medvedev D. A., Vasil'ev V. P., Vasil'eva E. D.
Acta Ichthyologica et Piscatoria
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2011
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tom 41
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nr 2
Background. A new taxonomy of tubenose gobies of the genus Proterorhinus has been proposed recently. However, some of taxonomic hypotheses have not been confirmed by recent genetic studies or seem not to correspond with ecological features and genetic differentiation of these fishes. The aim of this paper was to test the new taxonomy through a phylogeographic analysis of the fish from 15 sites in Southern Ukraine and Russia, through analyzing the genotypes deposited in the GenBank and to define the range of those species. Materials and methods. Fin clips were sampled from 52 specimens of tubenose gobies collected from 2003 up to 2009 in 15 localities of the Ponto-Caspian basin. Genomic DNA for amplification of mitochondrial cyt b gene fragment (about 408 bp) was extracted using the Diatom®DNA Prep 100. The haplotype MedianJoining Network was constructed using the Network 4.5.1.0. software. Results. Tubenose gobies from the Black Sea basin are represented by two euryhaline species historically distributed in different areas: P. semilunaris in the north-western part of the Black Sea basin (and possibly eastern Aegean basin) and P. marmoratus in the north-eastern part. The hypothesis about freshwater and marine Black Sea Proterorhinus species seems to be not probable. The validity of endemic Crimean P. tataricus is not confirmed, several independent findings presume it to be conspecific with P. marmoratus. Some Crimean rivers and reservoirs are populated by P. semilunaris which could spread from the Dnieper River basin through the Severo-Krymskyi channel or may be accidentally introduced. The populations from the Caspian Sea and Sea of Azov basins represent the distinct evolutionary lineage of tubenose goby. But their taxonomic state should be analyzed by further molecular genetic studies of a wide scope of Caspian samples. Conclusion. The present data on the variability of the mitochondrial cyt b gene fragment in different tubenose goby populations result in revision of some previous taxonomic hypotheses in this fish group. At the same time further molecular genetic researches of Caspian populations seem to be the main tool for future development of taxonomic conclusions.
4

Ponticola iranicus sp. nov. (Actinopterygii: Perciformes: Gobiidae) from the Caspian Sea basin

81%
Vasil'eva E. D., Mousavi-Sabet H., Vasil'ev V.
Acta Ichthyologica et Piscatoria
|
2015
|
tom 45
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nr 2
Background. Five species of Ponticola have hitherto been recognized among freshwater gobies in the Ponto–Caspian basin. In 2014 a number of specimens representing this genus were collected in northern Iran. The detailed morphological and karyological study of those gobies collected revealed significant differences between them and their known congeners. The aim of this study was to describe these fish as a new species from the Caspian Sea basin. Materials and Methods. The fish specimens were collected in August 2014 at two localities of the Sefid-Rud River drainage, and in the Gisum River, Guilan Province, northern Iran. In total, 18 specimens were used for karyological study following a previously described method. Both karyotyped and intact specimens were then morphologically investigated using characters developed for study on gobiids, and particular for freshwater Caucasian gobies. The comparative materials were specimens from museum collections, as well as published descriptions, illustrations, and measurements of other species. Results. Ponticola iranicus sp. nov. differs from its congeners in a set of the following features: D1 VI, D2 I/(14½) 15½ – 17½, A I/10½ – 13½; nape scaled completely, scales cycloid; cycloid scales covering upper part of opercle; lateral line system with posterior sub-orbital row d2 continuous; predorsal area uniform, dark grey; first dorsal fin with oblique black stripe between first two or three rays; short dark grey strip on upper part of pectoral fin base; karyotype consisting of 46 acrocentric chromosomes. Conclusion. All known Ponto–Caspian gobies demonstrate mosaic pattern of morphological and karyological features that presumes their polyphyletic origins. Further phylogenetic studies by molecular genetic methods are necessary for identification of their marine ancestors and clarifying of common trends in the evolution of the Ponto–Caspian goby group.
5

Reproductive capacities in the polyploid males of spined loaches from the unisexual-bisexual complex, occurred in the Moscow River

71%
Vasil'ev V.P., Akimova N. V., Emel'yanova N.G., Pavlov D. A., Vasil'eva E.D.
Folia Biologica
|
2003
|
tom 51
|
nr Suppl.
6

The karyotype of the Amu Darya sturgeon, Pseudoscaphirhynchus kaufmanni (Actinopterygii: Acipenseriformes: Acipenseridae)

61%
Kovalev K. V., Balashov D. A., Cherniak A. L., Lebedeva E. B., Vasileva E. D., Vasilev V. P.
Acta Ichthyologica et Piscatoria
|
2014
|
tom 44
|
nr 2
Background. Karyological studies of acipenserid fishes are of great importance because they present the only direct method to evaluate their ploidy levels for further research on polyploid evolution in these fishes. They are also important for prediction of the results of interspecific hybridizations in sturgeon aquaculture. None of the species of the genus Pseudoscaphirhynchus has hitherto been studied karyologically. The aim of this paper was to present the first data on the karyotype of the dwarf form of Pseudoscaphirhynchus kaufmanni (Kessler, 1877). Materials and Methods. Three females of the dwarf form of Pseudoscaphirhynchus kaufmanni of the total body length 19–23 cm were caught in the Vakhsh River (Amu Darya River drainage), Tadzhikistan, in 2012. The chromosome slides were prepared by using previously published karyological method of Vasil’ev and Sokolov. Totally, 14 metaphase plates were analyzed. Results. The karyotype of Pseudoscaphirhynchus kaufmanni consists of 118–120 chromosomes and includes about 18–20 large bi-armed chromosomes, about 32–34 small bi-armed chromosomes, from one to two pairs of large acrocentrics, and about 64 small acrocentrics or microchromosomes. Conclusion. The karyological study revealed that Pseudoscaphirhynchus kaufmanni belongs to low-chromosome acipenserid group with about 120 chromosomes. Its karyotype demonstrates noticeable differences from the karyotype of the shovelnose sturgeon, Scaphirhynchus platorhynchus (Rafinesque, 1820), in the number of large acrocentrics, thereby, karyological data confirms polyphyletic origin of the subfamily Scaphirhynchinae (or tribe Scaphirhynchini).
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