Pygmarrhopalites Vargovitsh, 2009

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 Pygmarrhopalites Vargovitsh, 2009

1 Appendices anales rod-like, with apical/subapical serration ( pygmaeus - type)..................................................................................................... 2 ( pygmaeus -group s. str. sensu Bretfeld 1999)

- Appendices anales different from pygmaeus - type ............................................................ 3

2 Antenna about 1.8× head length; Ant III without subbasal papilla; Ant IV with 5 subsegments separated by a single suture; appendices anales with short denticles; dens with 2 outer and 3 inner spines..... P. pygmaeus ( Wankel, 1860) (troglophile)

- Antenna about 3.5× head length; Ant III with subbasal papilla; Ant IV with 9–10 subsegments separated by several annuli; appendices anales with longer denticles; dens with one outer spine.............. P. rystsovi Vargovitsh, 2022 (troglobiont)

3 Appendices anales with spoon-shaped tip.. P. cochlearifer ( Gisin, 1947) ( cochlearifer -group sensu Bretfeld 1999) (epigean)

- Appendices anales palmated, multibranched ( principalis - type)................ 4 ( principalis -group sensu Bretfeld 1999)

4 Ant IV with 11 subsegments.................................................. P. arbaicus sp. nov. (troglobiont)

- Ant IV with 7 or fewer subsegments...................................................................... 5

5 Ant IV with 7 subsegments.............................................. P. dbari Vargovitsh, 2017 (troglobiont)

- Ant IV with 6 or fewer subsegments...................................................................... 6

6 Ant IV with 6 subsegments............................................................................. 7

- Ant IV with 5 subsegments............................................................................. 8

7 Antenna about 2.8× head length; Ant IV with naked intercalary pseudosubsegments between normal subsegments; head dorsum without spine-like setae; dens with 2 outer spine-like setae and one thickened inner seta; empodium III with corner tooth; empodia not reaching claw tips............................................... P. trisetosus sp. nov. (troglobiont)

- Antenna about 1.5× head length; Ant IV without naked intercalary pseudosubsegments; spine-like setae on head dorsum present; dens with 2 outer and 3 inner spine-like setae; empodium III without corner tooth; empodia overtopping claw tips..................................................................... P. principalis ( Stach, 1945) (troglophile)

8 Antenna about 2.3× head length; empodia I–III not reaching claw tips............ P. kovali Vargovitsh, 2017 (troglobiont)

- Antenna about 1.5× head length; empodia I–III overtoping claw tips............................................ 9

9 Head dorsum with stout spine-like setae.................................... P. secundarius ( Gisin, 1958) (epigean)

- Head dorsum with ordinary or weakly thickened setae........................ P. sericus ( Gisin, 1947) (subtroglophile)