Speciation and species classification of allopatric populations : beyond the DNA barcoding

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Researches on speciation and species classification of allopatric populations of 14 land bird taxa(19 species) were conducted through DNA analyses, morphological analyses and ecological analyses including vocal analysis of songs. As the results, extremely various patterns of the population structure and speciation of land birds in and around the Japanese Archipelago were found. That is to say, molecular analyses suggested that the population structures of land bird species discord with the geological history of the Ryukyu Islands, and extremely various patterns of population differentiations at every species are found. Locations of geographical boundary line are various in each species as well as the degree of genetic differentiation and the age of population division. Furthermore, the degree of morphological division and ecological division are also various and they are not concordant with that of genetic division all time. Evolution of songs may be influenced from coexistence or not of the related species, namely it is 'character displacement' of songs. Morphological adaptive evolution may be accelerated from the adaptive behavior to artificial environmental change, cultivation of nearly whole an islet. We suggested the need of reinvestigation to revision of subspecies in several species, e. g. Ryukyu Scops Owl Otus elegans and Narcissus Flycatcher Ficedula narcissina, and even to revision of species in some species, e. g. Taczanowski's Grasshopper Warbler Locustella pleskei and Brown-eared Bulbul Hypsipetes amaurotis. We have finished revision of species and subspecies only in Arctic Warbler Phylloscopus borealis and White's Thrush Zoothera dauma in the period of this research project, thus the other revisions remain to future studies.