Two new sympatric species of Songius from Mount Fanjing, Southwest China (Coleoptera: Staphylinidae: Pselaphinae)

The ant-loving beetle genus Songius Yin & Li, 2010 (Coleoptera: Staphylinidae: Pselaphinae: Batrisini) is rarely collected due to a cryptic myrmecophilous lifestyle, and its diversity remains insufficiently explored. Here we describe two new sympatrically distributed species from Mount Fanjing, Guizhou Province, Southwest China. Songius brevisetus sp. nov. is characterized by the relatively parallel-sided body with a densely setose integument, and different forms of the spines/projections of the legs and the aedeagus. Songius hubenqii sp. nov. differs in the shiny, almost asetose body segments and antennomeres 1–6, the mesofemora lacking tubercles and bearing long bristles on the ventral margins, and a different form of the aedeagus. A re-examination of the types and additional material supported the conclusion that S. hlavaci Zhao, Yin & Li, 2010 is a widely distributed species in eastern, central and southwestern China, leading to the placement of S. pseudohlavaci Yin & Li 2015, syn. nov. from Hunan as its junior synonym; and the species is newly recorded from Fujian and Chong­qing. An updated key and a distribution map for the genus are provided.