Arrhopalites Börner, 1906

Vargovitsh, Robert S., 2025, Antennal troglomorphy in Arrhopalitidae (Collembola: Symphypleona) with the description of two new cave Pygmarrhopalites Vargovitsh, 2009 species from the Arabika Massif in the Caucasus, Zootaxa 5673 (4), pp. 523-556 : 552

Key to species of the Caucasian Arrhopalites Börner, 1906

1 Spine-like setae on head dorsum present; cuticular spines on female Abd VI present; claws without clear modifications; tip of mucro swollen....................................................................................... 2

- Spine-like setae on head dorsum absent; cuticular spines on female Abd VI absent; claws much elongated; tip of mucro not swollen............................................................................................. 3

2 Head dorsum with 13 spine-like setae; antenna about 1,5× head length; Ant III not modified; Ant IV without distinct subsegmentation; claw III with inner tooth and tunica......................... A. caecus ( Tullberg, 1871) (troglophile)

- Head dorsum with 9 spine-like setae; antenna 2× head length; Ant III with basal swelling; Ant IV with 5–7 subsegments separated by several weakly developed annuli; claw III without inner tooth and tunica.............................................................................................. A. abchasicus Vargovitsh, 2013 (troglobiont)

3 Head dorsum with three axial setae; empodium III without corner tooth; dorsal valve of female Abd VI with 11 + 2 axial setae per side........................................................... A. colchicus Vargovitsh, 2025 (troglobiont)

- Head dorsum with four axial setae; empodium III with corner tooth; dorsal valve of female Abd VI with 10 + 2 axial setae per side................................................................................................ 4

4 Circumanal setae broadened, finely denticulated, and laterally serrated; appendices anales smooth and acuminate; femur II with 12 setae; claws I and II without inner tooth............................. A. macronyx Vargovitsh, 2012 (troglobiont)

- Circumanal setae ordinary; appendices anales apically denticulated; femur II with 13 setae; claws I and II with minute inner tooth............................................................ A. profundus Vargovitsh, 2022 (troglobiont)