Genetic differentiation of black and grey colored forms of the earthworm Drawida ghilarovi Gates, 1969 (Moniligastridae, Oligochaeta) on Russian Far East

• Molecular data for D. ghilarovi showed high differentiation between black and grey colored forms.
• Phylogenetic relationships of D. ghilarovi black form are corresponded with the geographical distribution.
• Specimens of the D. ghilarovi were closely related to the Chinese D. japonica japonica.

The endemic earthworm Drawida ghilarovi Gates 1969, which is found in the Primorye and the south of the Khabarovsk Krai, is represented in the forest by a live form of aneciques (burrowing) and in the wetland by soil-litter (epigeic) worms. These moniligastrida species noticeably differ both in pigmentation (grey and black forms, respectively) and in ecology specifics. Molecular analysis of these specimens has been performed using partial sequences of the mitochondrial COI and 16S genes. The genetic p-distances between the two colored forms of D. ghilarovi and within the black form of this species have been estimated and the phylogenetic relationships of these different forms reconstructed using the maximum parsimony and maximum likelihood algorithms. Genetic differentiation within the genus Drawida ranged from 16.3 to 23% when using the COI gene sequence data. Genetic differences between the colored forms of D. ghilarovi were 14.8–16.9%, suggesting species level differentiation between these forms. Phylogenetic relationships, based on the combined molecular data, showed obvious differentiation between the grey and black forms of D. ghilarovi. In addition, there was also considerable differentiation between different samples of the D. ghilarovi black forms, collected from different geographical locations.

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