A new species of Arrhopalites Börner (Collembola, Symphypleona, Arrhopalitidae) from China, with a key to the Asian species of the caecus group

The second species of Arrhopalites from China is described and illustrated and an identification key to the Asian species of the caecus group is presented. Arrhopalitesbrevicornissp. nov. is the eleventh species of the caecus group recorded in Asia and it can be clearly differentiated by the unguiculus III with 2 internal teeth (0–1 in all other species). Also, the combination of antennae less than 2 times the size of the head, antennal segment IV without annulations, 1+1 eyes, dorsal head with 9 spines, 2+2 regular spines per side on the anal valves, circumanal chaetae without basal serrations, subanal appendage long and apically serrated, manubrium with 5+5, and dorsal dens with 16 chaetae is unique among the Asian species of the caecus group.