Lagynochthonius, Beier, 1951

Hou, Yanmeng, Gao, Zhizhong & Zhang, Feng, 2022, Diversity of cave-dwelling pseudoscorpions from eastern Yunnan in China, with the description of eleven new species of the genus Lagynochthonius (Pseudoscorpiones, Chthoniidae), Zootaxa 5198 (1), pp. 1-65 : 61-62

Key to the species of Lagynochthonius from China

1 Carapace without antero-median setae; trichobothrium sb closer to b than to st .................................... 2

- Carapace with antero-median setae; trichobothrium sb closer to st than to b or midway between st and b ................ 3

2 Chela 7.03 (♂) times as long as broad (length 2.04 mm), hand 2.62 (♂) times longer than broad (length 0.76 mm), movable chelal finger 1.71 (♂) times longer than hand (movable chelal finger length 1.30 mm); epistome pointed and small, triangular; trichobothrium sb of movable chelal finger 1.07 times as far from b as from st .................. L. xinjiaoensis sp. nov.

- Chela 6.44–6.46 (♂), 5.87–6.04 (♀) times as long as broad (length 1.55–1.61 (♂), 1.69–1.76 (♀) mm), hand 2.44–2.54 (♂), 2.27–2.36 (♀) times longer than broad (length 0.61 (♂), 0.66–0.68 (♀) mm), movable chelal finger 1.57–1.62 (♂), 1.56–1.57 (♀) longer than hand (movable chelal finger length 0.96–0.99 (♂), 1.03–1.07 (♀) mm); epistome small and obtuse, rounded; trichobothrium sb of movable chelal finger 1.28–1.30 times as far from b as from st ............ L. magnidentatus sp. nov.

3 Carapace without eyes or eyespots....................................................................... 4

- Carapace with eyes or eyespots......................................................................... 10

4 At least one finger of chela with intercalary teeth............................................................ 5

- Both chelal fingers without intercalary teeth............................................................... 17

5 Only fixed chelal finger with intercalary teeth.............................................................. 6

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

6 The intercalary teeth round and obtuse; the teeth on movable chelal fingers retrorse and contiguous; chela length 1.57–1.61 (♂), 1.64–1.69 (♀) mm; movable chelal finger length 0.93–0.96 (♂), 0.99–1.01 (♀) mm................ L. retrorsus sp. nov.

- The intercalary teeth small and pointed; the teeth on movable chelal fingers pointed and well-spaced; chela length 2.07–2.16 (♂), 2.06–2.19 (♀) mm; movable chelal finger length 1.24–1.25 (♂), 1.20–1.26 (♀) mm.......... L. spinulentus sp. nov.

7 Tergites I–III each with 2 setae.......................................................................... 8

- Tergites I–III each with 4 setae.................................................... L. yaowangguensis sp. nov.

8 Palpal femur 7.57–7.64 (♂) times as long as broad (length 1.06–1.07 mm), chela length 1.53–1.54 (♂) mm; trichobothrium sb situated midway between st and b ............................................................ L. fengi sp. nov.

- Palpal femur 8.07–8.93 (♂) times as long as broad (length 1.21–1.25 mm), chela length 1.68–1.76 (♂) mm; trichobothrium sb closer to st than to b ................................................................................... 9

9 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; trichobothrium sb of movable chelal finger 1.22–1.24 times as far from st as from b; trichobothrium t situated slightly distal to it ........................ L. serratus sp. nov.

- 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; trichobothrium sb of movable chelal finger 1.67 times as far from st as from b; trichobothrium t situated slightly basal to it ............................................ L. xiaolinensis sp. nov.

10 Troglomorphic species with a larger body size and elongate appendages: body length not less than 1.80 (♂, ♀) mm, chela length not less than 1.5 (♂, ♀) mm; without corneate eyes, only anterior pair of eyespots present............. L. crassus sp. nov.

- Epigean species with smaller body size and without elongate appendages: body length not more than 1.60 (♂, ♀) mm, chela length not more than 1.00 (♂, ♀) mm; with corneate eyes, anterior pair of eyes well developed...................... 11

11 Four corneate eyes, posterior pair of eyes well developed; tergites I and II each with 2 setae..................................................................................................... L. medog Zhang & Zhang, 2014

- Two corneate eyes, posterior pair of eyes reduced to eyespots; tergites I and II each with 4 setae..................... 12

12 Carapace with a distinct triangular epistome........................................... L. niger Hu & Zhang, 2012

- Carapace without epistome or with extremely indistinct epistome.............................................. 13

13 At least one finger of chela with intercalary teeth........................................................... 14

- Both chelal fingers without intercalary teeth............................................................... 15

14 Only fixed chelal finger with intercalary teeth....................................... L. harveyi Hu & Zhang, 2014

- Both chelal fingers with intercalary teeth............................................ L. tonkinensis ( Beier, 1951)

15 Movable chelal finger more than 1.20 (♂, ♀) times longer than hand; proximal half of movable finger with rounded vestigial teeth.............................................................................................. 16

- Movable chelal finger 1.03 (♂) times, 0.97–1.00 (♀) times longer than hand; proximal half of movable chelal finger without vestigial teeth........................................................ L. brachydigitatus Zhang & Zhang, 2014

16 Chelal hand 2.50–2.87 (♂) times, 2.39–2.75 (♀) as long as broad; trichobothrium sb of movable chelal finger 2 times as far from st as from b; tergites I–VII with 4 setae..................................... L. leptopalpus Hu & Zhang, 2012

- Chelal hand 2.00 (♂) times as long as broad; trichobothrium sb of movable chelal finger 1.5 times as far from st as from b; only the tergites I–II with 4 setae......................................................... L. sinensis (Beier, 1967)

17 Tergites I–II each with 2 setae........................................ L. laoxueyanensis Hou, Gao & Zhang, 2022

- Tergites I–II each with 3–4 setae........................................................................ 18

18 Carapace with a distinct triangular epistome................................................ L. xibaiensis sp. nov.

- Carapace with a round and obtuse epistome............................................................... 19

19 Larger: body length 2.55–2.92 (♂), 2.72–2.95 (♀) mm; chela length 1.85–2.22 (♂), 1.94–2.03 (♀) mm....................................................................................... L. bailongtanensis Li, Liu & Shi, 2019

- Smaller: body length 0.98–1.23 (♂), 1.28–1.30 (♀) mm; chela length 0.76–0.85 (♂), 0.85–0.86 (♀) mm. L. minimus sp. nov.