Key to adults of the Chthonius -related genera (coxae II and III with coxal spines)

1 Intercoxal tubercle absent.............................................................................. 2

- Intercoxal tubercle present, bisetose.......................................................................4

2 Trichobothrium sb of movable chelal finger placed approximately halfway between trichobothria b and st .............. 3

- Trichobothrium sb of movable chelal finger distinctly closer to st than to b, forming with st and t a separate group with respect to b ....................................................................... Spelyngochthonius Beier, 1955

3 Chela not lagyniform, fixed finger sigmoid in lateral view. Distal marginal seta on pedipalpal coxa distinctly longer than distal marginal seta on coxa I.......................................................... Microchthonius Hadži, 1933

- Chela lagyniform, fixed finger straight in lateral view. Distal marginal seta on pedipalpal coxa (dcs) markedly shorter than the

distal marginal seta on coxa I (dps).................................................. Cantabrochthonius n. gen. 4 Male genitalia with median hiatus dividing each row of internal guard-setae into two groups of two setae................................................................................. Hesperochthonius Muchmore, 1968, n. stat.

- Male genitalia without median hiatus dividing each row of internal guard-setae................................... 5

5 Coxal spines of coxa II arranged in a transverse row............................... Neochthonius Chamberlin, 1929

- Coxal spines of coxa II irregularly arranged in a rounded patch................................................ 6

6 Chela lagyniform; chelal fingers mostly with large, upright and well-spaced teeth; apodeme of movable chelal finger usually well developed and strongly sclerotized.................................................................. 7

- Chelal not lagyniform, hand fusiform; chelal fingers usually with more or less close-set teeth, distinctly reclined backwards; apodeme of movable chelal finger absent or poorly developed............................ Chthonius C.L. Koch, 1843

7 Proximal portion of chelal hand with 4 setae in adults and tritonymphs, seta hp3 present. Tip of fixed chelal finger of male, tritonymph and deutonymph usually without a deep hollow on paraxial face and subapical protuberance (sp) (sometimes present in Globochthonius); without a medial protuberance (ip) between chelal condyles............................... 8

- Proximal portion of chelal hand with 3 setae in adults and tritonymphs, seta hp3 absent. Tip of fixed chelal finger of male, tritonymph and deutonymph with a deep hollow on paraxial face and subapical protuberance (sp); medial protuberance (ip) present between chelal condyles.......................................... Ephippiochthonius Beier, 1930, n. stat.

8 Chelal hand distad of trichobothria ib / isb with a rounded hump and a marked hollow before base of movable finger; base of chelal hand without a pronounced hump dorso-paraxially; third tooth of normal row (mt) of fixed chelal finger modified in shape and deviated in orientation with respect to the other teeth; movable chelal finger lacking lyrifissures ma1 and ma2 ..................................................................................... Occidenchthonius n. gen.

- Chelal hand without a hump distad of trichobothria ib / isb, gradually constricted distad of trichobothria ib / isb and without hollow before base of movable finger; base of chelal hand with a pronounced hump dorso-paraxially; third tooth of normal row (mt) of fixed chelal finger neither modified in shape nor deviated in orientation with respect to the other teeth; lyrifissures ma1 and ma2 present on movable chelal finger...................................... Globochthonius Beier, 1931, n. stat.