Lagynochthonius Beier, 1951

Genus Lagynochthonius Beier, 1951 View in CoL

Type species: Chthonius johni Redikorzev, 1922 , by original designation.

Tyrannochthonius (Lagynochthonius) Beier, 1951: 61 .

Lagynochthonius Beier View in CoL : Chamberlin, 1962: 314; Murthy & Ananthakrishnan, 1977: 16–17; Harvey, 1989: 21; Harvey, 1991: 182; Muchmore, 1991: 113; Harvey, 1999: 247; Edward & Harvey, 2008: 280.

Key to the species of genus Lagynochthonius View in CoL from China

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

- Carapace without eyes or eyespots.................................. 20

2. Eyes well-developed.......................................................... 3

- Eyes strongly reduced...................................................... 14

3. Tergites I and II each with two setae ................................. 4

- Tergites I and II each with four setae ................................ 6

4. Epistome present ............................................................... 5

- Epistome absent................ L. medog Zhang & Zhang, 2014 View in CoL

5. Fixed chelal finger with intercalary teeth............................ .......................................... L. duo Sun, Guo & Zhang, 2024

- Fixed chelal finger without intercalary teeth....................... ........................................ L. houi Sun, Guo & Zhang, 2024

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

- Both chelal fingers without intercalary teeth................... 10

7. Both chelal fingers with intercalary teeth.......................... 8

- Only fixed chelal finger with intercalary teeth.................. 9

8. Carapace with a hump-shaped epistome; four eyes well-developed............. L. hepingensis Sun, Guo & Zhang, 2024

- Carapace with a flat, rounded epistome; posterior pair of eyes spot-like ........................... L. tonkinensis ( Beier, 1951) View in CoL

9. Carapace without epistome.................................................. ........................................ L. harveyi Zhang & Zhang, 2014 View in CoL

- Carapace with a hump-shaped epistome ............................. ..................................... L. gibbus Sun, Guo & Zhang, 2024

10. Epistome present ............................................................. 11

- Epistome absent............................................................... 12

11. Epistome triangular; pedipalpal chela length 0.75–0.93 mm, 5.17–6.25 times as long as broad ................................ ................................................. L. niger Hu & Zhang, 2012 View in CoL

- Epistome hump-shaped; pedipalpal chela length 0.68–0.73 mm, 6.80–7.30 times as long as broad ................................ ............................ L. sanhuaensis Sun, Guo & Zhang, 2024

12. Four eyes well-developed................................................13

- Anterior pair of eyes well-developed, posterior pair of eyes reduced to eyespots.............................................................. ........................... L. brachydigitatus Zhang & Zhang, 2014 View in CoL

13. Pedipalpal chela length 0.72 mm, 4.80 times as long as broad............................................. L. sinensis ( Beier, 1967) View in CoL

- Pedipalpal chela length 0.95–1.00 mm, 5.56–6.33 times as long as broad.................. L. leptopalpus Hu & Zhang, 2012 View in CoL

14. Carapace with four strongly reduced eyes........................... .......................................................... L. baiguensis sp. nov.

- Carapace only with two eyespots .................................... 15

15. Tergites I and II each with two setae ............................... 16

- Tergites I and II each with four setae .............................. 18

16. Epistome present .................................... L. zhaoae sp. nov.

- Epistome absent............................................................... 17

17. The length of chela femur (0.78 mm) and pedipalpal chela (1.08 mm); chela femur 7.80 (♀) times longer than broad.. ........................................................ L. zhakouensis sp. nov.

- The length of chela femur (0.61 mm) and pedipalpal chela (0.88 mm); chela femur 5.54 (♀) times longer than broad.. .................................................... L. longquanensis sp. nov.

18. Epistome triangular; pedipalpal chela length 1.61 mm (♂), 1.69–1.77 mm (♀) ................................ L. infirmus sp. nov.

- Epistome obtuse and small, round; pedipalpal chela length not more than 1.60 mm (♂ ♀) .......................................... 19

19. Pedipalpal chela 7.00–7.14 (♂), 6.40–6.46 (♀) times as long as broad (length 1.54–1.57 (♂), 1.55–1.60 (♀) mm); palpal femur 8.21–8.50 (♂), 7.50–7.87 (♀) times as long as broad (length 1.15–1.19 (♂), 1.18–1.20 (♀) mm).............. .................................. L. crassus Hou, Gao & Zhang, 2022

- Pedipalpal chela 7.33–7.67 (♂), 6.71–6.82 (♀) times as long as broad (length 1.32–1.38 (♂), 1.41–1.50 (♀) mm); palpal femur 6.92–7.23 (♂), 6.80–7.29 (♀) times as long as broad (length 0.90–0.94 (♂), 1.02 (♀) mm)........................ .............................. L. latipectus Hou, Feng & Zhang, 2023

20. Carapace without antero-median setae; trichobothrium sb closer to b than to st ........................................................ 21

- Carapace with antero-median setae; trichobothrium sb closer to st than to b or midway between st and b .......... 22

21. Epistome pointed and small, triangular; pedipalpal chela 7.03 (♂) times as long as broad (length 2.04 mm) ............. ........................... L. xinjiaoensis Hou, Gao & Zhang, 2022

- Epistome small and obtuse, rounded; pedipalpal chela 6.44– 6.46 (♂), 5.87–6.04 (♀) times as long as broad (1.55–1.61 (♂), 1.69–1.76 (♀) mm) ..................................................... ....................... L. magnidentatus Hou, Gao & Zhang, 2022

22. At least one chela finger with intercalary teeth .............. 23

- Both chelal fingers without intercalary teeth.................. 32

23. Only fixed chelal finger with intercalary teeth............... 24

- Both chelal fingers with intercalary teeth....................... 26

24. Movable chelal finger teeth markedly retrorse and contiguous............... L. retrorsus Hou, Gao & Zhang, 2022

- Movable chelal finger teeth upright and contiguous ...... 25

25. Tergite Ⅹ with two setae; pedipalpal chela length 1.79–1.85 mm (♀), chela femur length 1.27–1.28 mm (♀), 8.47–8.53 (♀) times as long as broad; trichobothrium sb situated midway between st and b ................................................... ............................ L. zhijinensis Hou, Feng & Zhang, 2023

- Tergite Ⅹ with four setae; pedipalpal chela length 2.06–2.19 mm (♀), chela femur length 1.47–1.48 mm (♀), 7.40–7.74 (♀) times as long as broad; trichobothrium sb slightly closer to st than to b ...... L. spinulentus Hou, Gao & Zhang, 2022

26. Tergites II and III each with four setae........................... 27

- Tergites II and III each with two setae ........................... 28

27. Tergites I with four setae; pedipalpal chela length 1.84 mm (♂), 1.83–1.91 mm (♀), 8.76 (♂), 8.30–8.32 (♀) times as long as broad; chela femur length 1.36 mm (♂), 1.35–1.41 mm (♀), 10.46 (♂), 10.07–10.38 (♀) times as long as broad; trichobothrium sb situated midway between st and b .................. L. yaowangguensis Hou, Gao & Zhang, 2022

- Tergites I with two setae; pedipalpal chela length 1.33 mm (♂), 1.26 mm (♀), 6.65 (♂), 6.63 (♀) times as long as broad; chela femur length 0.93 mm (♂), 0.89 mm (♀), 7.15 (♂), 7.42 (♀) times as long as broad; trichobothrium sb slightly closer to st than to b .......................................... ...................... L. longedentatus Hou, Feng & Zhang, 2023

28. Tergites IⅤ and Ⅹ each with four setae ............................... ................................................. L. guangyangensis sp. nov.

- Tergites IⅤ and Ⅹ each with two setae ........................... 29

29. Trichobothrium sb slightly closer to st than to b ............ 30

- Trichobothrium sb situated midway between st and b ... 31

30. Carapace markedly narrowed posteriorly; chela 8.38–8.84 (♂) times as long as broad, hand 3.38–3.58 (♂) times longer than broad; proximal half of movable chelal finger without vestigial teeth........... L. serratus Hou, Gao & Zhang, 2022

- Carapace gently narrowed posteriorly; chela 7.00 (♂) times as long as broad, hand 2.92 (♂) times longer than broad; proximal half of movable chelal finger with 6 vestigial teeth ................... L. xiaolinensis Hou, Gao & Zhang, 2022

31. Pedipalpal chela length 1.53–1.54 mm (♂), 1.53–1.55 mm (♀); chela femur length 1.06–1.07 mm (♂), 1.08–1.15 mm (♀); fixed chelal finger with 23–25 macrodenticles, slightly retrorse and pointed, plus 14– 15 intercalary microdenticles ...................................... L. fengi Hou, Gao & Zhang, 2022

- Pedipalpal chela length 1.88–1.99 mm (♂), 1.89–2.01 mm (♀); chela femur length 1.35–1.39 mm (♂), 1.36–1.41 mm (♀); fixed chelal finger with 31–36 macrodenticles, slightly retrorse and pointed, plus 27– 31 intercalary microdenticles ........................ L. guanniuensis Hou, Feng & Zhang, 2023

32. Tergites I and II each with two setae .............................. 33

- Tergites I and II each with four setae ............................. 38

33. Tergites Ⅹ with two setae .................................................... ............................. L. nigriculus Hou, Feng & Zhang, 2023

- Tergites Ⅹ with four setae............................................... 34

34. Tergites III and IⅤ each with two setae............................... ........................... L. daidaiensis Hou, Feng & Zhang, 2023

- Tergites III and IⅤ each with four setae ......................... 35

35. Epistome triangular ............................................................. ...................... L. laoxueyanensis Hou, Gao & Zhang, 2022

- Epistome hump-shaped .................................................. 36

36. Pedipalpal chelal length 0.78–0.83 mm (♂), 0.85 mm (♀) mm; fixed chelal finger teeth for numbers 17–19 .............. ................................................... L. jingshengensis sp. nov.

- Pedipalpal chelal length at least 0.87 mm; fixed chelal finger teeth for numbers at least 23 ................................ 37

37. Chelal finger 1.64 (♂), 1.55–1.61 (♀) times longer than hand, hand 1.89–2.25 (♂), 2.28–2.32 (♀) times as long as broad................... L. maanensis Hou, Feng & Zhang, 2023

- Chelal finger 1.56–1.59 (♂), 1.48–1.50 (♀) times longer than hand, hand 2.27–2.43 (♂), 2.35–2.38 (♀) times as long as broad.............. L. tuoluoensis Hou, Feng & Zhang, 2023

38. Galea present .................................................................. 39

- Galea completely vestigial ............................................. 43

39. Galea helmet-shaped ........................... L. galeatus sp. nov.

- Galea bump-shaped ........................................................ 40

40. Epistome triangular L. xibaiensis Hou, Gao & Zhang, 2022

- Epistome hump-shaped .................................................. 41

41. Trichobothrium sb situated midway between st and b ... 42

- Trichobothrium sb slightly closer to st than to b ................. ....................... L. mawangensis Hou, Feng & Zhang, 2023

42. Pedipalpal chela length 1.26–1.32 mm (♂), 1.38 mm (♀), 6.63–6.95 (♂), 5.75 (♀) times as long as broad; chela femur length 0.90–0.95 mm (♂), 0.99 mm (♀), 6.79–7.50 (♂), 7.07 (♀) times as long as broad.......................................... ........................ L. longyanensis Hou, Feng & Zhang, 2023

- Pedipalpal chela length 0.93 mm (♂), 0.89–0.96 mm (♀), 6.20 (♂), 6.00–6.85 (♀) times as long as broad; chela femur length 0.66 mm (♂), 0.63–0.66 mm (♀), 6.00 (♂), 5.73– 6.00 (♀) times as long as broad.......................................... .............................. L. xiaoensis Hou, Feng & Zhang, 2023

43. Trichobothrium sb situated midway between st and b ........ ............................ L. biyunensis Hou, Feng & Zhang, 2023

- Trichobothrium sb slightly closer to st than to b ............ 44

44. Epistome small, obtuse........................................................ ............................... L. bailongtanensis Li, Liu & Shi 2019 View in CoL

- Epistome obvious ........................................................... 45

45. Epistome peak-shaped; pedipalpal chela length 1.51–1.52 mm (♂), 1.39–1.62 mm (♀), 8.44–8.88 (♂), 7.48–8.10 (♀) times as long as broad; chela femur length 1.09 mm (♂), 1.00–1.21 (♀), 9.08 (♂), 8.07–10.08 (♀) times as long as broad ...................................................... L. apexus sp. nov.

- Epistome hump-shaped; pedipalpal chela length 0.76–0.85 mm (♂), 0.85–0.86 mm (♀), 6.07–6.33 (♂), 6.14–6.54 (♀) times as long as broad; chela femur length 0.56–0.60 mm (♂), 0.59–0.61 mm (♀), 6.67–7.00 (♂), 5.90–6.10 (♀) times as long as broad......................................................... ................................. L. minimus Hou, Gao & Zhang, 2022