Tyrannochthonius, Chamberlin, 1929

Hou, Yanmeng, Feng, Zegang & Zhang, Feng, 2023, Diversity of cave-dwelling pseudoscorpions from Guizhou in China, with the description of twenty-four new species of the genus Tyrannochthonius (Pseudoscorpiones, Chthoniidae), Zootaxa 5262 (1), pp. 1-158 : 153-155

Key to the species of Tyrannochthonius from China (subspecies not included)

1 Carapace with eyes or eyespots.......................................................................... 2

- Carapace without eyes or eyespots....................................................................... 6

2 Without corneate eyes, only anterior pair of eyespots present................................... T. infirmus sp. nov.

- With at least a pair of well-developed corneate eyes......................................................... 3

3 Chelal finger with intercalary teeth....................................................................... 4

- Chelal finger without intercalary teeth.................................................................... 5

4 Troglomorphic species with larger body size and elongate appendages: e.g. body length min. 1.73 (♂, ♀) mm, palpal femur length min. 0.76 (♂, ♀) mm................................................................. T. duo sp. nov.

- Epigean species with smaller body size and without elongated appendages: e.g. body length 1.20 (♀) mm, palpal femur length 0.47 (♀) mm...................................................................... T. robustus Beier, 1951

5 Carapace with 18 setae and a dentate epistome; tergites VIII‒IX each with 8 setae......... T. japonicus (Ellingsen, 1907)

- Carapace with 16 setae and a small triangular epistome; tergites VIII‒IX each with 6 setae..................................................................................................... T. pachythorax Redikorzev, 1938

6 At least one finger of chela with intercalary teeth............................................................ 7

- Both chelal fingers without intercalary teeth............................................................... 23

7 Only fixed chelal finger with intercalary teeth.............................................................. 8

- Both chelal fingers with intercalary teeth................................................................. 11

8 Tergites I–III each with 2 setae; carapace anterior margin with 6 setae........................................... 9

- Tergites I–III each with 4 setae; carapace anterior margin with 4 setae......................................... ... 10

9 More chelal finger teeth: e.g. fixed chelal finger with 28‒30 macrodenticles, plus 14‒ 15 intercalary microdenticles, 42‒45 in total; smaller body size but longer appendages: e.g. body length 1.96–2.06 (♂), 2.12–2.58 (♀) mm; chela length 2.08–2.11 (♂), 2.27–2.29 (♀) mm; movable chelal finger 1.63–1.76 times longer than hand and 0.60–0.62 times longer than chela............................................................................................. T. gracilis sp. nov.

- Fewer chelal finger teeth: e.g. fixed chelal finger with 26‒28 macrodenticles, plus 3‒ 4 intercalary microdenticles, 30‒31 in total; larger body size but shorter appendages: e.g. body length 2.29–2.62 (♂), 2.64–2.66 (♀) mm; chela length 1.89–1.93 (♂), 2.02–2.05 (♀) mm; movable chelal finger 1.53–1.55 times longer than hand and 0.58 times longer than chela............................................................................................. T. parcidentatus sp. nov.

10 Epistome present; body length 1.64 (♀) mm, chela 5.39 (♀) times longer than board (length 1.24 (♀) mm); chelal fingers with fewer teeth: fixed chelal finger with 31–32 teeth, movable chelal finger with 6–7 teeth, smooth and well-spaced.............................................................................. T. chixingi Gao, Wynne & Zhang, 2018

- Epistome absent; body length 1.40 (♀) mm, chela 6.37 (♀) times longer than board (length 1.21 (♀) mm); chelal fingers with more teeth: fixed chelal finger with 37 teeth, movable chelal finger with 26 teeth, retrorse, pointed and continuous............................................................................... T. zhai Gao, Zhang and Chen, 2020

11 Tergites I–II each with 2 setae.......................................................................... 12

- Tergites I–II each with 4 setae........................................................................ ... 14

12 Smaller: body length max. 2.10 (♀) mm, palpal femur length max. 0.97 (♀) mm, chela length max. 1.44 (♀) mm; tergite IV with 4 setae........................................................................................ 13

- Larger: body length 2.41 (♀) mm, palpal femur length 1.39 (♀) mm, chela length 1.98 (♀) mm; tergite IV with 2 setae........................................................................................ T. qilinensis sp. nov.

13 With a slightly slender chela: hand 2.50 (♀) times, femur 6.60 (♀) times, chela 7.70 (♀) times longer than broad; fewer numerous intercalary teeth; trichobothrium sb indistinctly nearer st than b ......................... T. akaelus Mahnert, 2009

- With a slightly stouter chela: hand 2.30 (♀) times, femur 5.90–6.70 (♀) times, chela 6.90–7.30 (♀) times longer than broad; more numerous intercalary teeth; trichobothrium sb slightly nearer b than st ............. T. ganshuanensis Mahnert, 2009

14 Smaller: body length max. 1.40 (♂), 1.69 (♀) mm; chela length max. 0.88 (♂), 0.93 (♀) mm; epistome small, obtuse.... 15

- Larger: body length min. 1.56 (♂), 1.77 (♀) mm; chela length min. 1.21 (♂), 1.24 (♀) mm; epistome large, pointed...... 17

15 Coxae II with 7–9 terminally indented coxal spines on each side; fewer fixed chelal finger teeth (40–44); chela 5.69–5.85 (♂), 5.57–5.75 (♀) times longer than board................................................................... 16

- Coxae II with 10 terminally indented coxal spines on each side; more fixed chelal finger teeth (56–57); chela 6.29–6.62 (♂), 6.07–6.20 (♀) times longer than board...................................................... T. arificus sp. nov.

16 Tergites VIII‒IX each with 6 setae; rallum with 7 pinnate blades; chela length 0.91–0.92 (♀) mm; palpal femur 4.92–5.08 (♀) times longer than board (length 0.59–0.61 (♀) mm); movable chelal finger 2.17–2.21 (♀) times longer than hand; trichobothrium sb nearer st than b ............................................................. T. yanshanensis sp. nov.

- Tergites VIII‒IX each with 5 setae; rallum with 8 pinnate blades; chela length 0.74–0.76 (♂), 0.78–0.79 (♀) mm; palpal femur 5.10–5.33 (♂), 5.00–5.30 (♀) times longer than board (length 0.48–0.51 (♂), 0.53–0.55 (♀) mm); movable chelal finger 2.12–2.13 (♂), 2.04 (♀) times longer than hand; trichobothrium sb midway between st and b ........ T. breviculus sp. nov.

17 Body length generally min. 2.00 (♂, ♀) mm, chela length min. 1.43 (♂, ♀) mm; palpal femur length min. 0.97 (♂, ♀) mm.. .................................................................................................. 18

- Body length max. 1.99 (♂) mm, chela length max. 1.29 (♂) mm; palpal femur length max. 0.89 (♂) mm T. hispidus sp. nov.

18 Trichobothrium sb nearer b than st or midway between st and b ............................................... 19

- Trichobothrium sb nearer st than b .......................................................... T. acutus sp. nov.

19 Shorter appendages: chela length max. 1.59 (♂, ♀) mm; palpal femur length max. 1.10 (♂, ♀) mm; femoropatella of leg IV length max. 0.93 (♂, ♀) mm........................................................................... 20

- Longer appendages: chela length min. 1.60 (♂, ♀) mm; palpal femur length min. 1.15 (♂, ♀) mm; femoropatella of leg IV length min. 1.01 (♂, ♀) mm........................................................................... 21

20 Movable chelal finger teeth markedly retrorse and continuous, without vestigial proximal half teeth; trichobothrium sb nearer b than st; rallum with 6–7 pinnate blades............................................... T. multidentatus sp. nov.

- Movable chelal finger teeth slightly retrorse and well-spaced, with vestigial proximal half teeth; trichobothrium sb midway between st and b; rallum with 8 pinnate blades............................................. T. maculosus sp. nov.

21 Trichobothrium sb nearer b than st; body length max. 2.35 (♂, ♀) mm, chela 7.27–8.00 times longer than board (length max. 1.76 (♂, ♀) mm), palpal femur 7.30–8.30 times longer than board; tergite VIII with 5–6 setae....................... 22

- Trichobothrium sb midway between st and b; body length min. 2.36 (♂, ♀) mm, chela 8.25–8.57 times longer than board (length min. 1.80 (♂, ♀) mm), palpal femur 8.50–8.79 times longer than board; tergite VIII with 4 setae.... T. altus sp. nov.

22 Intercalary teeth present in the distal 2/3 of fixed chelal finger and till trichobothrium sb of movable chelal finger; tergite VII with 4 setae, tergite X with 4–5 setae; chela 7.9–8.0 (♂), 6.9–7.55 (♀) times longer than broad; coxae II with 12–15 terminally indented coxal spines on each side; rallum with 8 pinnate blades...................... T. antridraconis Mahnert, 2009

- Intercalary teeth present in tips (nearly 1/3) of both chelal fingers only; tergite VII with 5 setae, tergite X with 2 setae; chela 7.27 (♂) times longer than broad; coxae II with 8–9 terminally indented coxal spines on each side; rallum with 7 pinnate blades................................................................................ T. babaowanensis sp. nov.

23 Chelal fingers straight or slightly curved in dorsal view...................................................... 24

- Chelal fingers markedly curved in dorsal view.................................. T. pandus Hou, Gao & Zhang, 2022

24 Epistome absent..................................................................................... 25

- Epistome present.................................................................................... 28

25 Tergites II–IV with 1–2 setae; trichobothrium sb nearer b than st .............................................. 26

- Tergites II–IV with 3–4 setae; trichobothrium sb nearer st than b .............................................. 27

26 Trichobothrium sb of movable chelal finger 1.20–1.22 times as far from st as from b; chela 8.44–9.06 (♂), 7.75–8.33 (♀) times longer than board; coxae II with 12–13 terminally indented coxal spines on each side................. T. umidus sp. nov.

- Trichobothrium sb of movable chelal finger 1.67–1.70 times as far from st as from b; chela 7.45–7.95 (♂), 7.52 (♀) times longer than board; coxae II with 8–9 terminally indented coxal spines on each side........................ T. pinguis sp. nov.

27 Fewer chelal fingers teeth: fixed chelal finger with 20–21 teeth, movable chelal finger with 25–26 teeth; slightly smaller body size (body length 1.81–1.94 (♂), 1.94–2.01 (♀) mm; chela length 1.34–1.46 (♂), 1.33–1.46 (♀) mm); rallum with 7 pinnate blades................................................................................ T. planus sp. nov.

- More chelal fingers teeth: fixed chelal finger with 30–32 teeth, movable chelal finger with 40–43 teeth; slightly larger body size (body length 1.80–2.09 (♂), 2.18–2.25 (♀) mm; chela length 1.45–1.57 (♂), 1.46–1.56 (♀) mm); rallum with 8 pinnate blades................................................................................. T. pictus sp. nov.

28 Tergites I–II each with 2 setae.......................................................................... 29

- Tergites I–II each with 3–4 setae........................................................................ 32

29 Tergites IV and X each with 4 setae; chela 7.27–7.50 times longer than board.................................... 30

- Tergites IV and X each with 2 setae; chela 7.53–8.20 times longer than board.................... T. multicavus sp. nov.

30 Carapace anterior margin with 6 setae and posterior margin with 2 setae; body length min. 1.73 (♂, ♀) mm, chela length min. 1.33 (♂, ♀) mm, palpal femur length min. 0.93 (♂, ♀) mm; rallum with 7–8 pinnate blades......................... 31

- Carapace anterior margin with 4 setae and posterior margin with 4 setae; body length max. 1.56 (♂, ♀) mm, chela length max. 1.30 (♂, ♀) mm, palpal femur length max. 0.88 (♂, ♀) mm; rallum with 6 pinnate blades................................................................................................. T. harveyi Gao, Zhang and Chen, 2020

31 Larger: body length 2.18–2.26 (♂), 2.33–2.53 (♀) mm, chela 7.27 (♂), 6.78–7.09 (♀) times longer than board (length 1.60 (♂), 1.56 (♀) mm), palpal femur length 1.11–1.17 (♂), 1.09–1.17 (♀) mm; movable chelal finger 1.74–1.79 (♂), 1.74–1.75 (♀) times longer than hand; trichobothrium sb nearer b than st; rallum with 7 pinnate blades............. T. oblongus sp. nov.

- Smaller: body length 1.73 (♂), 2.12 (♀) mm, chela 7.39 (♂), 7.53 (♀) times longer than board (length 1.33 (♂), 1.43 (♀) mm), palpal femur length 0.93 (♂), 1.00 (♀) mm; movable chelal finger 2.05 (♂), 2.00 (♀) times longer than hand; trichobothrium sb midway between st and b; rallum with 8 pinnate blades................................... T. brevispinus sp. nov.

32 Movable chelal finger teeth slightly retrorse and well-spaced; coxae II with 10–12 terminally indented coxal spines on each side............................................................................................... 33

- Movable chelal finger teeth markedly retrorse and continuous; coxae II with 13–15 terminally indented coxal spines on each side................................................................................. T. quattuor sp. nov.

33 Larger: body length 2.59–2.80 (♂), 2.91–3.11 (♀) mm, chela 2.14–2.34 (♂), 2.37–2.46 (♀) mm, movable chelal finger 1.41– 1.46 times longer than hand, palpal femur length 1.58–1.68 (♂), 1.67–1.75 (♀) mm; trichobothrium sb nearer st than b; rallum with 7 pinnate blades; tergite IV with 4 setae................................................... T. latus sp. nov.

- Smaller: body length 2.59–2.75 (♂), 2.83 (♀) mm, chela 1.92–1.97 (♂), 1.85 (♀) mm, movable chelal finger 1.78–1.86 times longer than hand, palpal femur length 1.34–1.35 (♂), 1.24 (♀) mm; trichobothrium sb nearer b than st; rallum with 8 pinnate blades; tergite IV with 5 setae........................................................ T. nanxingensis sp. nov.