Extension of west boundary of Moniligastridae (Oligochaeta) in East Asia: Integrative taxonomy discloses a new species of the genus Drawida Michaelsen, 1900 from Northwest China

A new earthworm species, Drawida xinjiangensis sp. nov., was described from the northwestern China using an integrative taxonomic approach that combined morphological examination and molecular data. The new species belongs to the Drawida japonica species complex (DjSC) and is distinguished from its congeners by its body length of 33–70 mm, clitellum in X – XIII (white laterally and dark brown medially), two to three gizzards, one pair of testis sacs suspended on septum 9 / 10 or 10 / 11, and cylindrical-shaped white prostate glands that are nearly as long as or longer than the testis sacs.

Molecular species delimitation: Assemble Species by Automatic Partitioning (ASAP), Generalised Mixed Yule Coalescent (GMYC), and Bayesian Phylogenetics and Phylogeography (BPP) consistently supported its species status assignment. Phylogenetic analyses based on the nuclear 28 S rRNA gene and mitogenomic data revealed that D. xinjiangensis sp. nov. forms an independent lineage within the DjSC. This discovery extends the west distribution of moniligastrid species to the arid and semi-arid regions in East Asia and highlights the hidden diversity of earthworms in this under-surveyed area.