Integrative taxonomy reveals exceptional species diversity of Lucasioides from China (Isopoda: Oniscidea: Agnaridae)

The genus Lucasioides Kwon, 1993 (Isopoda: Oniscidea: Agnaridae) occurs in Asia, but confined only to China, Japan, Korea, and Russian Siberia. The ambiguously morphological differences among some members of the genus make a dilemma: the species recognition, whether morphologically similar or different, is uncertain. In this paper, we present first morphometric and molecular data for the genus from a broad sample. DNA sequences (mitochondrial COI, nuclear 18S rRNA, 28S rRNA, and NaK) were generated and integrated with morphological evidence to reveal the cryptic species and delimit the new species within the genus. Seven species are described as new to science: Lucasioides digitatus sp. nov., L. dissectus sp. nov., L. dianensis sp. nov., L. formosus sp. nov., L. gracilentus sp. nov., L. schmidti sp. nov. and L. subcurvatus sp. nov. To date, Lucasioides species from China are 44.4% as many as all the known congeners worldwide, showing the exceptional species diversity of Lucasioides species from China. The results demonstrate that the integrative taxonomy is especially important to reveal the cryptic species among the high morphological similarity of taxa, as well as providing an effective way for species identification to accelerate the exploration of woodlice biodiversity.