Molecular differentiation of epigeic and anceic forms of Drawida ghilarovi Gates, 1969 (Moniligastridae, Clitellata) in the Russian Far East: Sequence data of two mitochondrial genes

Mitochondrial cytochrome oxidase subunit I (COI) and 16S rRNA gene sequence data were analysed for 43 specimens of Drawida ghilarovi - earthworms of a tropical genus on the northern boundary of their natural habitat, including two ecological forms and three colour morphs collected from different regions of the southern Russian Far East. Intraspecific genetic differentiation of these clitellata was analysed with different criteria that characterise different forms and morphs. A sample of anecic worms was shown to possess higher genetic variation than a sample of epigeic worms. Haplotype network reconstructions showed that the meadow-swamp epigeic black-coloured D. ghilarovi is more highly diverged from the anecic forest grey- and brown-coloured worms than the grey and brown colour morphs are from each other. Genetic differentiation between three colour morphs ranged from 9.89 ± 0.58 to 11 ± 0.59% using COI and 16S data. An AMOVA test and an exact test showed a high probability of non-differentiation between grey and brown earthworms. A multimodal mismatch distribution was revealed for the whole D. ghilarovi sample and for each colour morph. The minimum spanning tree showed that the differentiation of specimens is associated with ecological and geographical criteria. Molecular data for Drawida showed high genetic differentiation between epigeic and anecic using COI and 16S gene sequence data as well as the various phylogenetic relationships among the studied forms. The anecic earthworms possibly represent different genetic lineages of the D. ghilarovi species complex. The epigeic Drawida, based on the complex data, can be considered a new species of this genus.