Resolving the phylogenetic position of Hygrobiidae (Coleoptera: Adephaga) requires objective statistical tests and exhaustive phylogenetic methodology: a response to Cai et al. (2020)

External and internal thoracic structures of two carabid species (Trechini) were examined documented with different techniques. The study has a main focus on the eyeless cave-dwelling specialist Sinaphaenops wangorum, but detailed information is also provided for occurring in cave entrances. phylogenetic background structural features skeletomuscular system was addressed. morphology compared to conditions observed previously studied carabids non-related subterranean leiodids (Staphylinoidea) order identify adaptations. Main character complexes linked cavernicolous habits Trechini are elongation pro- mesothorax legs, complete irreversible reduction flight apparatus. lost capacity far reaching modification skeletal elements metathorax including strongly shortened simplified metanotum, metaventrite, completely reduced wings sclerites wing base. elongate prothorax together long slender head elongated legs distinctly increases activity range lightless environment, which likely facilitates foraging carnivorous beetles. Some like loss anterior thorax found some Leiodidae (Leptodirini), whereas other members staphylinoid family have compact body normal length. In contrast predaceous Trechini, Leptodirini scavengers.