The Alpine region harbours one of the most diverse subterranean faunas in the world, with many species showing extreme morphological modifications. The ground beetles of tribe Trechini (Coleoptera, Carabidae) are among the best studied and widespread groups with abundance of troglobionts, but their origin and evolution is largely unknown.

Three new species of the genus Guiodytes Tian, 2013 are described from the limestone caves of Guangxi Zhuang Autonomous Region, southern China: Guiodytes weii Huang & Faille sp. nov. and Guiodytes yueliangensis Huang & Tian sp. nov. from Dapo Dong and Huang Dong caves, respectively, in Huanjiang County, northernmost Guangxi; Guiodytes inexpectatus Tian & Zhou sp. nov. from the Zhuzhu Dong cave in Longzhou County, southwestern Guangxi. All of the six known species of Guiodytes are endemic to Guangxi, ranging from the southwest to the northernmost. A modified key to species and a distribution map for Guiodytes are provided.

The trechine beetle fauna (Coleoptera, Carabidae) of the Ethiopian Highlands is known to be highly diverse in species, and many species groups were recognized to be characterized by unusual character states of external and genital morphology. Earlier authors described several genera and subgenera of Ethiopian Trechina endemic to certain high mountains of the country. However, the relationships of these species groups and their evolutionary history are unknown so far. Here, we present the first molecular phylogenetic analysis of Ethiopian Trechina, detect several synonymic names under Trechus sensu lato, and introduce two new species groups to the country’s fauna: the monotypic genus Baehria Schmidt & Faille, gen. nov., with the type species B. separatasp. nov. from Mt. Choke in northern Ethiopia, and the Trechus subgenus Abunetrechus Schmidt & Faille, subgen. nov., with the type species T. bipartitus Raffray, 1885; this subgenus includes three species of northern Ethiopia. We show that the composition of the Ethiopian fauna is based on multiple events of immigration, which started simultaneously with or some million years after the Oligocene-Early Miocene orogenic events north and south of the Rift Valley. Our results support the habitat island hypothesis for the evolution of the Ethiopian highland fauna. We found no evidence for an alternative hypothesis assuming a close connection of the Trechina immigration to Ethiopia and Pleistocene cooling. We, thus, conclude that the geomorphological development rather than the climatic changes are the main drivers of the diversification of the high-altitude Trechina fauna in Ethiopia.