Abstract
Extensive litter sampling at eight forested localities in Yunnan and Sichuan detected 381 specimens of Micropeplinae rove beetles. DNA barcoding data from 85 representative specimens were analysed to delimit species and infer their relationships. Statistical methods were implemented to assess regional species diversity of understudied Micropeplinae. The total number of sampled Micropeplinae species varied between 14 and 17, depending on a splitting versus lumping approach for allopatric populations. A single Micropeplinae species was sampled in six of eight studied localities, three species were found on Mount Gongga, while ten species were discovered on hyperdiverse Mount Emei in Sichuan. All Micropeplinae specimens from our samples belong either to the genus Cerapeplus, or to three other inclusive groups temporarily retained inside Micropeplus sensu lato. Each of the three groups potentially represents a separate genus: tesserula group, sculptus group and Micropeplus sensu stricto. A new species Micropeplus jason sp. n. from Mount Emei in Sichuan is described. Numerous illustrations introduce regional fauna and clarify the discussed morphological characters.