On the probable ways of penetration of an ancestral form of the Caucasian black grouse Lyrurus mlokosiewiczi to the Caucasus

Several years ago, studying the history of formation of endemic bird species in the Caucasus, we made an assumption on the Ciscaucasian way of occupying the Caucasus by an ancestral form of the Caucasian Black Grouse Lyrurus mlokosiewiczi and Eastern Palearctic origin of the species (Dzhamirzoev 2004, 2007), and about lesser probability for the formation of a specialized mountain form of the Black Grouse in Southern Europe and its further penetration to the Caucasus through Asia Minor as it had been supposed by R.L.Potapov (1985). Higher probability of the Ciscaucasian way of occupation is proved by the fact that the Black Grouse Lyrurus tetrix penetrated the same way to the Caucasus in historical times. It is shown that after first strong cold spells in late Pliocene – early Pleistocene the ancestor of the Caucasian Black Grouse had no insurmountable ecological barriers to penetrate from the north and Ciscausacia to the Caucasus. An argument for a lesser probability of an initial formation of the mountain form in Southern Europe and its further penetration to the Caucasus through mountains of Asia Minor (Potapov 1985) is absence of any specialized mountain forms of the Black Grouse in mountains of Europe. A much higher morphological diversity of geographical races in Eastern Palearctic, compared to Europe, speaks in favour of Eastern Palearctic origin of the gender Lyrurus. To confirm or reject the assumptions on the possible ways of formation of the Caucasian Black Grouse and genus Lyrurus as a whole, it is panned a comparative DNA analysis of the Lyrurus mlokosiewiczi and Lyrurus tetrix within the entire range of these species.