Differentiation within the genus Leptocarabus (excl. L. kurilensis) in theJapanese Islands as deduced from mitochondrial ND5 gene sequences (Coleoptera, Carabidae)

The phylogenetic trees have been constructed for the mitochondrial ND5 gene sequences from the Japanese Leptocarabus ground beetles, which contain 101 specimens collected from nearly the complete distribution ranges of them c onsisting of five morphological species, i.e., Leptocarabus procerulus, L. kumagaii, L. hiurai, L. kyushuensis and L. arboreus. On the trees, there ar e recognized two major lineages, each of which is further divided into two or more sublineages. The phylogenetic lines are geographically linked. Two or more species occur in a single lineage, and the same species appear in d ifferent lines. We suggest that transformation from one type of morphology to another took place in parallel in various periods of evolution of the Ja panese Leptocarabus. From the phylogenetic tree and the dating from the nuc leotide substitution rate and the geohistorical data it is inferred that th e ancestry of all the Japanese Leptocarabus species was derived from a prot oform of L. kyushuensis inhabited the ancient Japan area, followed by separ ation into two lineages after split of the Japanese Islands from the Eurasi an Continent. They then propagated distribution to occupy their own habitat ranges, during which the morphological transformation took place in some l ineages.