Absorbing hybridization of cobitis taenia and sabanejewia aurata (Cypriniformes, Cobitidae) in water reservoirs of northern Ukraine connected with diploid-polyploid complex formation

Absorbing Hybridization of Cobitis taenia and Sabanejewia aurata (Cypriniformes, Cobitidae) in Water Reservoirs of Northern Ukraine Connected with Diploid-Polyploid Complex Formation. Mezhzherin, S. V., Pukhtayevych, P. P., Tsyba, А. А. — In the rivers of the Northern Ukraine by meams of karyological and allozyme analysys obtained extensive natural hybridization between Cobitis taenia and Sabanejewia aurata, initially leading to the formation of diploid hybrids. Besides that certain water bodies are predominantly populated by triploids of the C. taenia — C. tanaitica — S. aurata biotypes. Since the share of this kind of hybrid biotypes signifi cantly exceeds the number of individuals of S. aurata, it is concluded that the hybridization of a common and eurybiontic C. taenia with rarer stenobiontic S. aurata, is of absorbing character

Is Evolution of Blind Mole Rats Determined by Climate Oscillations?

The concept of climate variability facilitating adaptive radiation supported by the ‘‘Court Jester’’ hypothesis is disputed by the ‘‘Red Queen’’ one, but the prevalence of one or the other might be scale-dependent. We report on a detailed, comprehensive phylo-geographic study on the ,4 kb mtDNA sequence in underground blind mole rats of the family Spalacidae (or subfamily Spalacinae) from the East Mediterranean steppes. Our study aimed at testing the presence of periodicities in branching patterns on a constructed phylogenetic tree and at searching for congruence between branching events, tectonic history and paleoclimates. In contrast to the strong support for the majority of the branching events on the tree, the absence of support in a few instances indicates that network-like evolution could exist in spalacids. In our tree, robust support was given, in concordance with paleontological data, for the separation of spalacids from muroid rodents during the first half of the Miocene when open, grass-dominated habitats were established. Marine barriers formed between Anatolia and the Balkans could have facilitated the separation of the lineage ‘‘Spalax’’ from the lineage ‘‘Nannospalax’’ and of the clade ‘‘leucodon’’ from the clade ‘‘xanthodon’’. The separation of the clade ‘‘ehrenbergi’’ occurred during the late stages of the tectonically induced uplift of the Anatolian high plateaus and mountains, whereas the separation of the clade ‘‘vasvarii’’ took place when the rapidly uplifting Taurus mountain range prevented the Mediterranean rainfalls from reaching the Central Anatolian Plateau. The separation of Spalax antiquus and S. graecus occurred when the southeastern Carpathians were uplifted. Despite the role played by tectonic events, branching events that show periodicity corresponding to 400-kyr and 100-kyr eccentricity bands illuminate the important role of orbital fluctuations on adaptive radiation in spalacids. At the given scale, our results supports the ‘‘Court Jester’’ hypothesis over the ‘‘Red Queen’’ one

KARYOTYPES AND MORPHOLOGICAL VARIABILITY OF CRAYFISH PONTASTACUS LEPTODACTYLUS AND P. ANGULOSUS (MALACOSTRACA, DECAPODA)

Karyotypes and Morphological Variability of Crayfis

Evidences of Multicomponent Structure of the Migratory Stock and Morphological Distinctions of Shads from the Genus Alosa (Clupeaformes, Alosiinae) of the Sea of Azov

Migratory stocks of shads passing through the Kerch strait during their seasonal migrations consist of three groups of specimens, that can be identified based on the number of gill rakers on the first arch. These are so called Kerch shad A. maeotica (50.2 %), Pontic shad A. immaculata (48.7 %) and Caspian shad A. caspia (1.1 %). This ratio of species in the region remains stable for the last 60 years. Populations of Kerch and Pontic shads have similar age structure and sex ratio with a shift toward females 52–54 %. Specimens of A. maeotica have greater linear size and weight than those of A. immacuta, that indicates higher growth rate of the former. Analysis of 26 body measurements shows definite differences between these shads in their absolute features, there are also some differences in the proportions of the head. Nevertheless, degree and reproducibility of interspecific differences during various periods of time, do not allow for the reliable discrimination of specimens of these species assumed by some researchers.Миграционные стада пузанковых сельдей, проходящие в период сезонных миграций через Керченский пролив, состоят из особей трёх групп, которые можно идентифицировать по числу жаберных тычинок на 1-й дуге. Это так называемая керченская сельдь, A.?maeotica (50,2 %), черноморско-азовская сельдь, A. immaculata (48,7 %), и пузанок, A. сaspia (1,1 %). Такое соотношение между этими видами в регионе остаётся стабильным на протяжении последних 60 лет. Популяции керченской и черноморско-азовской сельдей имеют одинаковую возрастную структуру и соотношение полов, при котором самки составляют 52–54 %. Особи A. maeotica отличаются от A. immaculata большими линейными размерами и массой, что свидетельствует о более высоком темпе их роста. Использование 26 промеров тела показывает определённые различия между этими сельдями по абсолютным признакам, также отмечаются некоторые различия и в пропорциях головы. Тем не менее масштаб и низкая воспроизводимость межвидовых различий в разные периоды не позволяют надежно дискриминировать особей этих предполагаемых некоторыми исследователями видов