A new species of the Drawida japonica species complex (Oligochaeta, Moniligastridae) disclosed by integrative taxonomy in Chongqing, China

The Drawida japonica (Michaelsen, 1892) species complex is widely distributed across Asia, yet its taxonomy remains challenging due to morphological conservatism and cryptic diversity. Using an integrative taxonomic approach, a new species, Drawida wuxiensis Qiao & Zhao, sp. nov., is described from the Yintiaoling National Nature Reserve in Chongqing, China. The new species is characterized by its small body size (22.0–47.0 mm), the absence of dorsal and female pores, and a unique comma-shaped spermathecae distinguished from the similar species D. japonica sensu stricto, D. henanensis Liu & Zhao, 2025, and D. sinensis Liu & Zhao, 2025 within the same complex.

Assemble Species by Automatic Partitioning (ASAP), the Generalized Mixed Yule Coalescent (GMYC) phylogenetic approach, and Bayesian Phylogenetics and Phylogeography (BPP) yielded congruent results recognizing the new species. Significant K 2 P genetic distances (18.0–19.9 %) from related species also further corroborate its validity. Molecular phylogenetic analyses, incorporating 13 protein-coding genes from the mitochondrial genome and four nuclear loci, collectively support its stable basal phylogenetic position and further confirm its species status as an early-diverging lineage.

This study revises the diversity profile of the D. japonica species complex and underscores the importance of integrating multiple lines of evidence for resolving species boundaries.