Phylogenetic relationships in genus Marmota and a history of palearctic marmots’ area. Filogenetitcheskie svyaei v rode Marmota I istoriya stanovleniya areala palearktitcheskikh sourkov. Relations phylogénétiques dans le genre Marmota et histoire de la zone de répartition des marmottes paléarctiques].

Résumé

A schema of Palearctic marmots’ phylogenesis based on molecular-genetical, karyological and literature data is offered. A time of divergence of a marmot phylum from common stem of ground squirrels is dated from Miocene according to as palaeontological so molecular-genetical data. An initial Pliocene differentiation had developed on the American territory. Marmots came into the Asia in the beginning of late Pliocene before a disappearance of Beringian Bridge when deforestation of the North-East Asia and north of Alaska was. At the time a caudata-like marmot with 2n=38 migrated in Asia. Primary expansion of marmots expanded from North and East to South and West simultaneously with a shifting of woodless zones from North to South. M. caudata differentiated in Central Asia and M. marmota formed in Europe at the beginning of Pleistocene. Other early Pleistocene marmots were low differentiated sibirica- or himalayana-like forms. Middle Pleistocene warm period (700-800 thousand years ago) led to a general outspread of forests. It caused disappearance of marmots in South-East Europe and a considerable reduction and fragmentation of marmot’s area in Asia. Probably, at that period a differentiation of himalayana and sibirica began. These forms had a big common area for a long time apparently. Maybe, M. menzbieri was isolated in Middle Asia at that period. A growth of periglacial landscapes promoted an expansion of marmots at the late Pleistocene. At that stage, marmots had advanced from South and East to North and West, from Middle Pleistocene China-Mongolian refugium where himalayana and sibirica forms differentiated. Sibirica-like form became an ancestor of a bobak-group and a sibirica-camtschatica group. M. sibirica and M. camtschatica had differentiated during the second part of Pleistocene in Trans-Baikalia. An ancestor of bobak-group had colonized territories of periglacial steppe of East Asia and Europe during second Pleistocene glaciation (nearly 100-600 thousand years ago) intensive forming geographical races. Mikoulin interglacial (75-130 thousand years ago) led to reduction and fragmentation of an area of bobak-group marmots. At that time bobak and baibacina forms began to differentiate. The last evolution occurrences are an isolation of 36-chromosomal kastschenkoi in West Siberia and emergence of intra-species forms of M. bobak. These events may be dated from 17-21 thousand years ago when the last global glacial was.