Karyological variation, reproductive isolation, morphological differentiation and geographic distribution of the cytotypes of Centaurea phrygia were investigated in Central Europe. Occurrence of two dominant cytotypes, diploid (2n = 22) and tetraploid (2n = 44), was confirmed and additionally triploid, pentaploid and hexaploid ploidy levels identified using flow cytometry. Allozyme variation as well as morphological and genome size data suggest an autopolyploid origin of the tetraploids. Crossing experiments and flow cytometric screening of mixed populations revealed strong reproductive isolation of the cytotypes. Multivariate morphometric analysis revealed significant differentiation between the cytotypes in several morphological characters (pappus length, length and colour of appendages on involucral bracts, involucre width). The cytotypes have a parapatric distribution with only a small contact zone: diploids occupy the whole of the Central and North European geographic range of the species except for the major part of the Western Carpathians, whereas tetraploids are confined to the Western Carpathians and adjacent areas, both cytotypes co-occurring only in a limited area of intra-montane basins of the Western Carpathians. Based on this array of data, taxonomic treatment of the cytotypes as autonomous species is proposed. The name Centaurea phrygia is applied to the diploids and the name C. erdneri belongs to the tetraploids; nomenclature of hybrids with C. jacea is also resolved.
We provide an updated distribution and dispersal rate of the European hare (Lepus europaeus Pallas, 1778) introduced in South America, with georeferenced record localities. According to our results the current geographic distribution of the European hare, would cover practically all of Argentina, Chile and Uruguay, southeastern Peru, southwestern Bolivia, southeastern Paraguay, and central part of southern Brazil. During the process of invading new areas, the hare has occupied very dissimilar environments, from the bushy steppes and Andean deserts of Bolivia and Peru to the dry and humid forests and wooded savannahs of Paraguay and Brazil. This would explain the variation observed in the dispersal rates that varied between 10 and 37 km/year.
The lamprey collections of the National Museum of Natural History – Sofia and the Regional History Museum – Ruse were examined in order to determine the species composition of the family Petromyzontidae in Bulgaria. In contrast to the four species of lampreys reported in the scientific literature as being present in Bulgaria, i.e. Lampetra fluviatilis, L. planeri, Eudontomyzon danfordi, and E. mariae, only the latter species was determined in the Bulgarian material. The distribution of this species in Bulgaria is restricted to the Danube River basin. The occurrence of E. hellenicus in the Bulgarian segment of the Struma River basin is anticipated in all probability. The species composition of lampreys inhabiting the streams emptying directly into the Black Sea remains to be investigated.
New records of the Ukrainian brook lamprey Eudontomyzon mariae (Berg, 1931) from the upper tributaries of the both Volga (Caspian Sea watershed) and Don (Black Sea watershed) river basins are documented. This significantly extends the range of the Ukrainian brook lamprey eastwards. The Ukrainian brook lamprey and the genus Eudontomyzon are the most distributed species and genus of the lampreys in Europe, respectively.
The nematode parasite Huffmanela huffmani Moravec, 1987 (Trichosomoididae) infects swimbladders of fishes in the family Centrarchidae. Only fish collected from the upper San Marcos River (Texas) have been found infected with H. huffmani eggs with a prevalence of 90%. Hundreds of thousands of H. huffmani eggs have been observed in these fish but only a few specimens of adult worms have ever been found. The San Marcos River arises from springs along the Balcones Fault Zone in San Marcos, Hays County, Texas. The restriction of the parasite to the upper San Marcos River and the high prevalence of the parasite eggs in centrarchids would seem to enable one to solve the life cycle of H. huffmani but this has proved false. Here, the insights and experiments used to help define some of the aspects concerning the life cycle of this enigmatic parasite are described. This study of H. huffmani includes a description of the habitat, the known limits of geographic distribution of the parasite, possible dispersal processes, egg characteristics, the testing of a possible intermediate host, Palaemonetes antrorum (Benedict) (Decapoda: Palaemonidae), and the effects of the digestion process on H. huffmani eggs.
In the order C. microphylla - C. intermedia - C. korshinskii, compensation irradiance, saturation irradiance, and optimum temperature for photosynthesis increased, net photosynthetic rate (PN) at low irradiance and low temperature decreased, optimum air humidity decreased, and PN at low air humidity increased. Daily cumulative value of PN increased while daily cumulative value of transpiration (E) decreased, and hence water use efficiency (WUE =PN/E) increased. Diurnal course of PN of C. microphylla was a double-peak curve, but the second peak in the curves of C. intermedia and C. korshinskii was not visible. These physiological characteristics are biological basis for the geographical distribution of these three Caragana species, and are in relation to water conditions of their habitats and distinctiveness in leaf hair of plant. and C. C. Ma ... [et al.].