The zappalai group:

31(3). Dorsal cuticle smooth or slightly rugose.................................................................. 32 -. Dorsal cuticle with small tubercles............................................................... D. taiwanus 32(31). Oral cavity armature present............................................................................33 -. Oral cavity armature absent or not visible under LM........................................................ 35 33(32). Oral cavity armature composed of a single dorsal tooth.......................................................34 -. Oral cavity armature with one anterior band of large teeth and one single medio-dorsal tooth in the posterior band.........

........................................................................................ D. turkmenicus 34(33). Configuration of macroplacoids 1> 2> 3, secondary branches of claws longer than 50% of the primary branches..........

.......................................................................................... D. mexicanus -. Configuration of macroplacoids 2> 1> 3, secondary branches of claws shorter than 50% of the primary branches.........

........................................................................................... D. bertolanii 35(31). Lunules on claws present, freshwater species........................................................ D. zappalai -. Lunules on legs absent, terrestrial species................................................................. 36 36(35). Claws without enlarged bases, ratio of the secondary to the primary branches more than 0.79............... D. longistipes -. Claws with enlarged bases............................................................................ 37 37(36). Long claws with a wide bulbous base.................................................. D. chetumalensis sp. nov. -. Claws without a wide bulbous base and with a ratio of the secondary to the primary branches less than 0.70............ 38 38(37). Ratio of the secondary to the primary branches of claws more than 0.60............................... D. qinlingense -. Ratio of the secondary to the primary branches of claws less than 0.55................................. D. korganovae