[Biogeography: geography or biology?].

General biogeography is an interdisciplinary science, which combines geographic and biological aspects constituting two distinct research fields: biological geography and geographic biology. These fields differ in the nature of their objects of study, employ different methods and represent Earth sciences and biological sciences, respectively. It is suggested therefore that the classification codes for research fields and the state professional education standard should be revised.

[Bivalve fauna succession in the north Pacific during the paleogene-neogene transition].

Cluster analysis was used to compare species composition of marine and brackish water bivalves in the Cenozoic deposits of the Russian Far East, Hokkaido, and California. Bivalvia species composition allows us to divide these deposits into two groups of clusters. The first group includes both extant and extinct species, while the second one is largely composed of extinct species. The drastic change in the bivalve species composition suggests that the base of the Uinin Horizon in the northern Sakhalin, Kuluven Horizon in the western Kamchatka, Tsubetsu Formation in eastern Hokkaido, and, possibly, the central part of the provincial Vaqueros Formation in California correspond to the Paleogene-Neogene boundary. The change in species composition was accompanied by the taxonomical diversity changes. At a higher level, the equitability of species richness among families significantly decreased.

[The continuity and discontinuity of the living cover: problem of the scale].

The reply to B.M. Mirkin's critical remarks (2005) concerning my paper "Continuity and discontinuity of the geomerida: the bionomic and biotic aspects" (Kafanov, 2005a) is given. The relationship between continuity and discontinuity of the living cover depends on the scale of study. The continuum mainly belongs to regularities of topological order. At regional, subglobal and global scale, the continuum of biochores is rather rare. The objective evidences of relative discontinuity of the living cover are determined by significant alterations of taxonomic richness at regional, subglobal and global scale.

[Principal stages in the Cenozoic diversification of shallow-water molluscan faunas in the North Pacific].

Cluster analysis of bivalve species recorded in Cenozoic deposits in Sakhalin Island, western Kamchatka, Hokkaido, and California was used to determine geological age of the modem North Pacific biogeographic region and its constituent subregions (Japan-Mandchurian, Beringian, and Oregon-Sitkan). The North Pacific region developed during the Paleogene-Neogene transition due to Drake Passage opening to deep-water movement, formation of the deep-water Antarctic Circumpolar Current, and the change in climate from greenhouse to psychospheric. Differentiation of the three subregions within the North Pacific Region seems to have occurred in late Miocene-early Pliocene, about 5.6 millions years ago and was probably due to the flooding of the Bering Land Bridge and development of the present configuration of circulation in the North Pacific. In the Northwest Pacific, during Paleogene and early Neogene, the faunal diversification occurred more rapidly and was more extensive than in the Northeast Pacific.

[Continuity and discontinuity of the geomerida: the bionomic and biotic aspects].

The view of the spatial structure of the geomerida (Earth's life cover) as a continuum that prevails in modern phytocoenology is mostly determined by a physiognomic (landscape-bionomic) discrimination of vegetation components. In this connection, geography of life forms appears as subject of the landscapebionomic biogeography. In zoocoenology there is a tendency of synthesis of alternative concepts based on the assumption that there are no absolute continuum and absolute discontinuum in the organic nature. The problem of continuum and discontinuum of living cover being problem of scale aries from fractal structure of geomerida. This problem arises from fractal nature of the spatial structure of geomerida. The continuum mainly belongs to regularities of topological order. At regional and subregional scale the continuum of biochores is rather rare. The objective evidences of relative discontinuity of the living cover are determined by significant alterations of species diversity at the regional, subregional and even topological scale Alternatively to conventionally discriminated units in physionomically continuous vegetation, the same biotic complexes, represented as operational units of biogeographical and biocenological zoning, are distinguished repeatedly and independently by different researchers. An area occupied by certain flora (fauna, biota) could be considered as elementary unit of biotic diversity (elementary biotic complex).

[Cluster analysis in biogeographical classifications]. / O primenenii klasternogo analiza v biogeograficheskikh klassifikatsiiakh.

Some unavoidable methodic and methodological problems arising at each stage of the classification of objects by the methods of hierarchical clustering are shown on the concrete (biogeographical) and abstract--numerical examples. Reasons which cause these problems and possible ways of minimization of cluster analysis artifacts are discussed. Unavoidable constrains in interpretations of dendrograms obtained by means of agglomerate algorithms are indicated.

[Genetic connections between some species of Mytilidae (Mollusca: Bivalvia) from the northern part of the Pacific Ocean]. / Geneticheskie sviazi mezhdu nekotorymi vidami Mytilidae (Mollusca: Bivalvia) severnoi chasti tikhogo okeana.

In 1978 and 1999, seven and eight species of Mytilidae (Mollusca: Bivalvia) were analyzed using gel electrophoresis. Mean heterozygosity per individual (Hobs and Hexp) and genetic distances (Rogers' DR, Nei's DN, and others) were estimated for 21 and 24 allozyme loci. Mytilus modiolus had the highest variation among the species examined. Genetic distances were lowest for the M. trossulus-M. galloprovincialis species pair: DR = 0.147, DN = 0.078. Overall, five species of the genera Mytilus and Crenomytilus were genetically closer to each other (DR = 0.147, DN = 0.078) than to the remaining three species of this group (DR = 0.807, DN = 2.243). The relationships among the species were examined using cluster analysis and parsimony methods. The densest clusters in the dendrograms consisted of (1) M. trossulus and M. galloprovincialis and (2) M. coruscus, M. californianus, and M. grayanus. These two clusters form a larger cluster (3), which comprises all representatives of the nominal genus Mutilus and C. grayanus. The Mytilus-Crenomytilus cluster is consecutively joined by Adula falcatoides, Mytilus modiolus, and Septifer keenae. According to Nei's genetic distances DN, the time of divergence between M. trossulus and M. galloprovincialis is 0.8-1.6 Myr; between M. californianus and C. grayanus, it is approximately 9 Myr; and between M. coruscus and the latter pair, it is 13 Myr before present. Two representatives of the Mytilus ex gr. edulis complex diverged from the Mytilus-Crenomytilus group of large-size Pacific species about 20 Myr ago. These results are in good agreement with paleontological data and indicate a relatively recent origin of the Mytilus ex gr. edulis complex. The results obtained can be used in systematics and phylogeny of modern Mytilidae.