Chthonius johni Redikorzev, 1922, by original designation.

Holotype ♂ (Ps.-MHBU-GX2022080201): China, Guangxi, Guilin City, Longsheng Autonomous County, Longji Town, Anjiangping Area, under topsoil and in the leaf litter layer [25°42′15.15″N, 110°3′3.87″E], 419 m a.s.l., 2 August 2023, Kun Yu & Jianzhou Sun leg. Paratypes: 3 ♂ (Ps.-MHBU-GX2022080203–05) and 1 ♀ (Ps.-MHBU-GX2022080202), all with the same data as the holotype.

The specific name is derived from the Latin word duo, meaning dual, which refers to the presence of two setae on both tergites I and II. A noun in apposition.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome triangular; tergites I and II each with two setae, III and IV each with four setae. Rallum with eight blades. Pedipalps slender, chela 6.17–7.27 (♂), 5.06 (♀) × as long as broad; femur 5.60–6.67 (♂), 6.70 (♀) × as long as broad; only fixed chelal finger with intercalary teeth and a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Males (holotype and paratypes) (Figs 1A, 2A–F, 3, 4).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker.

Cephalothorax (Figs 2D, 3A): carapace nearly subquadrate, 0.95–0.97 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrate; epistome small and triangular; four well-developed eyes; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 10 or 11 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 3D); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 2C, 3B): almost as long as carapace, 1.76–1.94 × as long as broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 11–17 teeth, distal one largest; movable finger with 13–18 retrorse contiguous small teeth; galea completely vestigial (Fig. 3B). Serrula exterior with 20 and serrula interior with 14 blades. Rallum with eight blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 3C).

Pedipalp (Figs 2A, B, E, 3E, 4A, B): trochanter 1.78–1.89, femur 5.60–6.67, patella 2.30–2.56, chela 6.17–7.27, hand 2.83–3.27 × as long as broad; femur 2.43–2.84 × as long as patella; movable chelal finger 1.11–1.27 × as long as hand and 0.55 × as long as chela. Setae generally long and acuminate. Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist at base of fixed chelal finger; esb and eb at almost the same level and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b and close to it (Figs 2A, 4A). Fixed chelal finger with sensilla af_1–2 close together, near tip; movable chelal finger with four sensilla: am_1–2 near tip, p₂ slightly distad of p₁, p₁ slightly distad of sb and very close to chelal teeth (Fig. 4A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 2B, 4B). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 17 or 18 well-spaced, pointed teeth, plus three or four intercalary microdenticles, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with six or seven well-spaced, pointed teeth, plus nine or ten vestigial, rounded, contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 4: 4: 4: 4: 4–5: 5–7: 5–6: 4: T2T: 0. Sternal chaetotaxy IV–XII: 8–10: 10–12: 11–12: 10–11: 10–12: 10–12: 9: -: 2. Genital region: sternite II with 6–10 setae scattered on median area, genital opening slit-like, sternite III with 18–20 setae (Fig. 3F).

Legs (Fig. 4C, D): fine granulation present on anterodorsal faces of trochanter IV, femur I; scale-like texture display on anterodorsal faces of femoropatella IV. Leg I: femur 1.71–1.94 × as long as patella; tarsus 1.88–2.13 × as long as tibia. Leg IV: femoropatella 2.65–2.81 × as long as deep; tibia 4.38–5.14 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.50–3.20 × as long as deep (TS = 0.35–0.53), telotarsus 9.25–12.00 × as long as deep and 2.29–2.47 × as long as basitarsus (TS = 0.23–0.33). Setae of leg I (trochanter to tibia) 3–5: 7–11: 6–7: 8–12, setae of leg IV (trochanter to basitarsus) 3: 3: 7–8: 8–9: 5–8. Arolium not divided, slightly shorter than the simple claws.

Adult female (paratype) (Figs 1B, 2G). Mostly same as males; tergal chaetotaxy I–XII: 2: 2: 4: 4: 4: 6: 6: 7: 7: 4: T2T: 0; sternal chaetotaxy IV–XII: 9: 12: 12: 10: 10: 11: 9: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 10 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.24–1.44. Pedipalps: trochanter 0.16–0.17/0.09 (1.78–1.89), femur 0.56–0.60/0.09–0.10 (5.60–6.67), patella 0.21–0.24/0.09–0.10 (2.30–2.56), chela 0.74–0.80/0.11–0.12 (6.17–7.27), hand 0.34–0.37/0.11–0.12 (2.83–3.27), movable chelal finger length 0.41–0.44. Chelicera 0.29–0.33/0.16–0.17 (1.76–1.94), movable finger length 0.20–0.21. Carapace 0.34–0.36/0.35–0.38 (0.95–0.97). Leg I: trochanter 0.10–0.12/0.08 (1.25–1.50), femur 0.29–0.33/0.06 (4.83–5.50), patella 0.17/0.05–0.06 (2.83–3.40), tibia 0.15–0.17/0.04 (3.75–4.25), tarsus 0.32–0.35/0.04 (8.00–8.75). Leg IV: trochanter 0.15–0.17/0.10 (1.50–1.70), femoropatella 0.45–0.53/0.16–0.20 (2.65–2.81), tibia 0.33–0.36/0.06–0.08 (4.38–5.14), basitarsus 0.15–0.17/0.05–0.06 (2.50–3.20), telotarsus 0.36–0.39/0.03–0.04 (9.25–12.00).

Females: body length 1.57. Pedipalps: trochanter 0.17/0.11 (1.54), femur 0.67/0.10 (6.70), patella 0.26/0.11 (2.36), chela 0.91/0.18 (5.06), hand 0.44/0.18 (2.44), movable chelal finger length 0.49. Chelicera 0.37/0.21 (1.76), movable finger length 0.23. Carapace 0.38/0.43 (0.88). Leg I: trochanter 0.18/0.10 (1.80), femur 0.35/0.07 (5.00), patella 0.18/0.06 (3.00), tibia 0.18/0.06 (3.00), tarsus 0.39/0.04 (9.75). Leg IV: trochanter 0.19/0.11 (1.73), femoropatella 0.59/0.22 (2.68), tibia 0.38/0.08 (4.75), basitarsus 0.18/0.07 (2.57), telotarsus 0.42/0.04 (10.50).

Lagynochthonius duo sp. nov. differs from all other epigean species of the genus Lagynochthonius from China except L. medog by the tergal chaetotaxy I–IV: 2: 2: 4: 4. It differs from L. medog in the presence of an epistome, which is absent in L. medog, and in the presence of only fixed chelal fingers with intercalary teeth in L. duo sp. nov., whereas both chelal fingers have intercalary teeth in L. medog (Beier 1951, 1967; Hu and Zhang 2012a, b; Zhang and Zhang 2014).

China (Guangxi).

Holotype ♂ (Ps.-MHBU-GZ2022070301): China, Guizhou Province, Tongren City, Jiangkou County, 500 m near Wanjiatun, under topsoil and in the leaf litter layer [27°43′32.5″N, 108°41′17.9″E], 509 m a.s.l., 3 July 2022, Yanmeng Hou, Lu Zhang, Nana Zhan, Jianzhou Sun & Long Lin leg. Paratype: 1 ♀ (Ps.-MHBU-GZ2022070302), all with the same data as the holotype, 2 ♂ (Ps.-MHBU-GZ2022062805–06) and 2 ♀ (Ps.-MHBU-GZ2022062803–04): Tongren City, Sinan County, Zhangjiazhai Town, 700 m near Zhangjiaping, under topsoil and in the leaf litter layer [27°56′39.16″N, 108°4′21.8″E], 731 m a.s.l., 28 June 20, Yanmeng Hou, Lu Zhang, Nana Zhan, Jianzhou Sun & Long Lin leg.

The specific name is derived from the Latin word gibbus, meaning hump-shaped, which refers to the shape of epistome. A noun in apposition.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome hump-shaped; tergites I–IV each with four setae. Rallum with eight blades. Pedipalps slender, chela 6.64–7.00 (♂), 5.12–5.69 (♀) × as long as broad; femur 5.78–7.00 (♂), 5.64–6.33 (♀) × as long as broad; only fixed chelal finger with intercalary teeth and a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Males (holotype and paratypes) (Figs 6A, 7A–F, 8, 9).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker.

Cephalothorax (Figs 7D, 8A): carapace nearly subquadrate, 0.97–1.03 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrate; epistome small and hump-shaped; four eyes, anterior pair of eyes well-developed, posterior pair with flat lenses; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 9–12 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 8D); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 7C, 8B): almost as long as carapace, 1.71–2.00 × as long as broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 12–15 teeth, distal one largest; movable finger with 16–18 retrorse contiguous small teeth; galea completely vestigial (Fig. 8B). Serrula exterior with 17–20 and serrula interior with 14–20 blades. Rallum with eight blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 8C).

Pedipalp (Figs 7A, B, E, 8E, 9A, B): trochanter 1.78–1.89, femur 5.78–7.00, patella 2.33–2.56, chela 6.64–7.00, hand 3.09–3.18 × as long as broad; femur 2.43–2.60 × as long as patella; movable chelal finger 1.15–1.20 × as long as hand and 0.53–0.55 × as long as chela. Setae generally long and acuminate. Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist forming a straight oblique row at base of fixed chelal finger; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b and close to it (Figs 7A, 9A). Fixed chelal finger with sensilla af_1–2 close together, near tip; movable chelal finger with four sensilla: am_1–2 near tip, p₂ slightly distad of sb, p₁ proximad of sb and very close to chelal teeth (Fig. 9A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 7B, 9B). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 20 or 21 well-spaced, pointed teeth, plus three or four intercalary microdenticles, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with 6–8 well-spaced, pointed teeth, plus 5–7 vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4: 5–6: 6–7: 6: 4: T2T: 0. Sternal chaetotaxy IV–XII: 10–12: 12–16: 10–13: 12–13: 12–13: 11–12: 9–10: -: 2. Genital region: sternite II with eight setae scattered on median area, genital opening slit-like, sternite III with 18–24 setae (Fig. 7F).

Legs (Fig. 9C, D): fine granulation present on anterodorsal faces of trochanter IV, femur I; scale-like texture display on anterodorsal faces of femoropatella IV. Leg I: femur 1.65–1.71 × as long as patella; tarsus 2.06–2.20 × as long as tibia. Leg IV: femoropatella 2.50–3.06 × as long as deep; tibia 4.43–4.71 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.33–3.40 × as long as deep (TS = 0.29–0.42), telotarsus 9.00–12.00 × as long as deep and 2.12–2.57 × as long as basitarsus (TS = 0.25–0.28). Setae of leg I (trochanter to tibia) 3–4: 7–11: 6–8: 8–9, setae of leg IV (trochanter to basitarsus) 3: 2–3: 4–7: 7–9: 6–10. Arolium not divided, slightly shorter than the simple claws.

Adult females (paratypes) (Figs 6B, 7G). Mostly same as males; tergal chaetotaxy I–XII: 4: 4: 4: 4–5: 5–6: 6: 5–6: 6: 5–8: 4–5: T2T: 0; sternal chaetotaxy IV–XII: 10–13: 11–13: 11–13: 10–14: 10–13: 10–13: 9–10: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 10–12 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.23–1.39. Pedipalps: trochanter 0.16–0.17/0.09 (1.78–1.89), femur 0.52–0.56/0.08–0.09 (5.78–7.00), patella 0.20–0.23/0.08–0.09 (2.33–2.56), chela 0.73–0.77/0.11 (6.64–7.00), hand 0.34–0.35/0.11 (3.09–3.18), movable chelal finger length 0.39–0.42. Chelicera 0.29–0.30/0.15–0.17 (1.71–2.00), movable finger length 0.18–0.19. Carapace 0.33–0.35/0.34–0.35 (0.97–1.03). Leg I: trochanter 0.10–0.11/0.08–0.09 (1.11–1.38), femur 0.28–0.30/0.06 (4.67–5.00), patella 0.17–0.18/0.05 (3.40–3.60), tibia 0.15–0.16/0.04 (3.75–4.00), tarsus 0.33/0.03–0.04 (8.25–11.00). Leg IV: trochanter 0.10–0.17/0.10–0.11 (1.00–1.70), femoropatella 0.48–0.50/0.16–0.20 (2.50–3.06), tibia 0.31–0.33/0.07 (4.43–4.71), basitarsus 0.14–0.17/0.03–0.04 (2.33–3.40), telotarsus 0.36/0.03–0.04 (9.00–12.00).

Females: body length 1.64–1.82. Pedipalps: trochanter 0.16–0.19/0.09–0.11 (1.60–1.78), femur 0.57–0.64/0.09–0.11 (5.64–6.33), patella 0.23–0.26/0.08–0.12 (1.92–2.30), chela 0.79–0.91/0.15–0.17 (5.12–5.69), hand 0.38–0.43/0.15–0.17 (2.53–2.69), movable chelal finger length 0.42–0.48. Chelicera 0.34–0.38/0.19–0.22 (1.72–1.79), movable finger length 0.21–0.24. Carapace 0.35–0.40/0.39–0.44 (0.88–0.91). Leg I: trochanter 0.12–0.13/0.07–0.09 (1.33–1.71), femur 0.29–0.33/0.06–0.07 (4.71–5.50), patella 0.16–0.19/0.04–0.06 (2.67–4.75), tibia 0.15–0.18/0.04–0.05 (3.60–3.75), tarsus 0.34–0.37/0.04 (8.50–9.25). Leg IV: trochanter 0.16–0.17/0.10–0.14 (1.14–1.70), femoropatella 0.49–0.56/0.18–0.22 (2.52–2.72), tibia 0.33–0.37/0.06–0.08 (4.50–4.71), basitarsus 0.17–0.19/0.06 (2.83–3.17), telotarsus 0.36–0.43/0.03–0.04 (10.00–12.00).

Lagynochthonius gibbus sp. nov. most closely resembles L. duo sp. nov. due to the presence of intercalary teeth only on the fixed chelal finger, the presence of eight blades on rallum, and similar size (chela length of males 0.73–0.80 mm, females 0.79–0.91 mm). However, the new species differs from L. duo sp. nov. in the shape of the epistome which is hump-shaped in L. gibbus sp. nov., but triangular in L. duo sp. nov., and in the number of setae on tergites I and II, with four setae on each in L. gibbus sp. nov. compared to two setae on each in L. duo sp. nov.

China (Guizhou Province).

Holotype ♂ (Ps.-MHBU-GZ2022080701): China, Guizhou Province, Qianxinan Prefecture, Wangmu County, Dayi Town, Heping Village, Near Provincial Highway 209, under topsoil and in the leaf litter layer [25°23′54.8″N, 106°7′37.08″E], 1553 m a.s.l., 7 August 2022, Yanmeng Hou, Lu Zhang, Jianzhou Sun & Wenlong Fan leg. Paratypes: 5 ♂ (Ps.-MHBU-GZ2022080702–06) and 2 ♀ (Ps.-MHBU-GZ2022080707–08), all with the same data as the holotype.

Named after the Heping Village, the type locality. A noun in apposition.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome hump-shaped; tergites I–IV each with four setae. Rallum with seven blades. Pedipalps slender, chela 6.08–6.82 (♂), 5.33–5.44 (♀) × as long as broad; femur 6.25–7.00 (♂), 6.20–6.30 (♀) × as long as broad; both chelal fingers with intercalary teeth, fixed chelal finger with a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Males (holotype and paratypes) (Figs 10A, 11A–F, 12, 13).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker.

Cephalothorax (Figs 11D, 12A): carapace nearly subquadrate, 0.97–1.03 × as long as broad, strongly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrate; epistome small and hump-shaped; four well-developed eyes; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 8–10 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 12D); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 11C, 12B): almost as long as carapace, 1.63–1.81 × as long as broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 9–12 teeth, distal one largest; movable finger with 12–15 retrorse contiguous small teeth; galea completely vestigial (Fig. 12B). Serrula exterior with 16–23 and serrula interior with 14–20 blades. Rallum with eight blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 12C).

Pedipalp (Figs 11A, B, 11E, 12E, 13A, B): trochanter 1.50–1.78, femur 6.25–7.00, patella 2.11–2.88, chela 6.08–6.82, hand 2.83–3.10 × as long as broad; femur 2.43–2.84 × as long as patella; movable chelal finger 1.11–1.27 × as long as hand and 0.53–0.57 × as long as chela. Setae generally long and acuminate. Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist at base of fixed chelal finger; esb and eb at almost the same level and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b and close to it (Figs 11A, 13A). Fixed chelal finger with sensilla af_1–2 close together, near tip; movable chelal finger with four sensilla: am_1–2 near tip, p₂ slightly distad of sb, p₁ proximad of sb and very close to chelal teeth (Fig. 13A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 11B, 13B). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 16–20 well-spaced, pointed teeth, plus 5–7 intercalary microdenticles, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with seven or eight well-spaced, pointed teeth, plus 2–5 intercalary microdenticles and six or seven vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4–5: 5–6: 5–7: 5–6: 4: T2T: 0. Sternal chaetotaxy IV–XII: 8–12: 10–12: 10–13: 10–12: 11–12: 10–12: 9: -: 2. Genital region: sternite II with 10 setae scattered on median area, genital opening slit-like, sternite III with 16–18 setae (Fig. 11F).

Legs (Fig. 13C, D): fine granulation present on anterodorsal faces of trochanter IV, femur I; scale-like texture display on anterodorsal faces of femoropatella IV. Leg I: femur 1.69–2.00 × as long as patella; tarsus 1.93–2.36 × as long as tibia. Leg IV: femoropatella 2.40–2.67 × as long as deep; tibia 4.00–4.71 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.50–2.80 × as long as deep (TS = 0.33–0.43), telotarsus 8.75–11.67 × as long as deep and 2.33–2.64 × as long as basitarsus (TS = 0.24–0.30). Setae of leg I (trochanter to tibia) 3–4: 8–10: 6–7: 7–10, setae of leg IV (trochanter to basitarsus) 2–3: 3–4: 6–8: 7–9: 6–10. Arolium not divided, slightly shorter than the simple claws.

Adult females (paratypes) (Figs 10B, 11G). Mostly same as males; tergal chaetotaxy I–XII: 4: 4: 4: 4–5: 5–6: 6: 6: 6–8: 6: 4: T2T: 0; sternal chaetotaxy IV–XII: 10–12: 12–13: 12–14: 11–12: 10–12: 8–11: 10: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 12 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.18–1.38. Pedipalps: trochanter 0.14–0.16/0.08–0.10 (1.50–1.78), femur 0.50–0.56/0.08–0.09 (6.25–7.00), patella 0.19–0.23/0.08–0.09 (2.11–2.88), chela 0.67–0.75/0.10–0.12 (6.08–6.82), hand 0.31–0.35/0.10–0.12 (2.83–3.10), movable chelal finger length 0.37–0.42. Chelicera 0.26–0.32/0.16–0.18 (1.63–1.81), movable finger length 0.15–0.18. Carapace 0.31–0.37/0.34–0.38 (0.89–1.09). Leg I: trochanter 0.10–0.12/0.07–0.10 (1.20–1.57), femur 0.26–0.30/0.05–0.06 (4.50–6.00), patella 0.15–0.16/0.05–0.06 (2.67–3.20), tibia 0.13–0.16/0.04 (3.25–4.00), tarsus 0.29–0.33/0.03–0.04 (7.25–11.00). Leg IV: trochanter 0.14–0.18/0.10–0.11 (1.36–1.63), femoropatella 0.44–0.50/0.17–0.20 (2.40–2.67), tibia 0.29–0.33/0.07–0.08 (4.00–4.71), basitarsus 0.13–0.15/0.05–0.06 (2.50–2.80), telotarsus 0.34–0.37/0.03–0.04 (8.75–11.67).

Females: body length 1.34–1.43. Pedipalps: trochanter 0.15–0.18/0.11–0.12 (1.25–1.64), femur 0.63–0.64/0.10 (6.20–6.30), patella 0.24–0.25/0.11–0.12 (2.08–2.18), chela 0.83–0.87/0.15–0.16 (5.33–5.44), hand 0.41–0.44/0.15–0.16 (2.73–7.75), movable chelal finger length 0.51–0.52. Chelicera 0.34–0.39/0.20 (1.70–1.95), movable finger length 0.21–0.23. Carapace 0.38–0.39/0.42 (0.90–0.93). Leg I: trochanter 0.11–0.13/0.09–0.10 (1.10–1.44), femur 0.32/0.06–0.07 (4.57–5.33), patella 0.16–0.17/0.06 (2.67–2.83), tibia 0.16–0.17/0.05 (3.2–3.4), tarsus 0.34–0.35/0.04–0.05 (6.80–8.75). Leg IV: trochanter 0.16–0.18/0.11–0.12 (1.45–1.50), femoropatella 0.54–0.55/0.18–0.21 (2.62–3.00), tibia 0.33–0.35/0.08–0.09 (3.89–4.12), basitarsus 0.16/0.06 (2.67), telotarsus 0.39/0.04 (9.75).

Lagynochthonius hepingensis sp. nov. most closely resembles L. tonkinensis in the presence of intercalary teeth on both chelal fingers and the presence of four setae on both tergal chaetotaxy I–II. However, it differs by the presence of a hump-shaped epistome and four well-developed eyes, whereas L. tonkinensis has a flat, rounded epistome and spot-like posterior pair of eyes (Beier 1951).

China (Guizhou Province).

Holotype ♂ (Ps.-MHBU-GZ2022080901): China, Guizhou Province, Qiannan Prefecture, Pintang County, Tangbian Town, Xindian Village, under topsoil and in the leaf litter layer [25°37′42.19″N, 106°43′55.15″E], 991 m a.s.l., 9 August 2022, Yanmeng Hou, Lu Zhang, Jianzhou Sun & Wenlong Fan leg. Paratypes: 2 ♂ (Ps.-MHBU-GZ2022080902–03) and 1 ♀ (Ps.-MHBU-GZ2022080904), all with the same data as the holotype.

This species is named for Yanmeng Hou, who participated in field work and collected some of the specimens. A noun in apposition.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome triangular; tergites I and II each with two setae, III and IV each with four setae. Rallum with eight blades. Pedipalps slender, chela 6.31–6.75 (♂), 5.20 (♀) × as long as broad; femur 5.90–6.78 (♂), 6.25 (♀) × as long as broad; chelal fingers without intercalary teeth, fixed chelal finger with a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Males (holotype and paratypes) (Figs 14A, 15A–F, 16, 17).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker.

Cephalothorax (Figs 15D, 16A): carapace nearly subquadrate, 0.91–0.97 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other aera smooth, without furrows; anterior margin smooth, without serrate; epistome small and triangular; four eyes, anterior pair of eyes well-developed, posterior pair with flat lenses; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 9–12 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 16D); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 15C, 16B): almost as long as carapace, 1.71–1.88 × as long as broad; five setae and three lyrifissures (including an exterior condylar lyrifissure, an exterior lyrifissure and extra lyrifissure (near sub basal setae)) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 9–12 teeth, distal one largest; movable finger with 11–13 retrorse contiguous small teeth; galea completely vestigial (Fig. 16B). Serrula exterior with 17–22 and serrula interior with 11–14 blades. Rallum with eight blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 16C).

Pedipalp (Figs 15A, B, E, 16E, 17A, B): trochanter 2.00–2.12, femur 5.90–6.78, patella 2.44–2.67, chela 6.31–6.75, hand 3.23–3.25 × as long as broad; femur 2.45–2.68 × as long as patella; movable chelal finger 0.95–1.05 × as long as hand and 0.49–0.51 × as long as chela. Setae generally long and acuminate. Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist forming a straight oblique row at base of fixed chelal finger; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, very close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b (Figs 15A, 17A). Fixed chelal finger with sensilla af_1–2 close together, near tip; movable chelal finger with four sensilla: am_1–2 near tip, p₂ slightly distad of sb, p₁ distad of p₂ and very close to chelal teeth (Fig. 17A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 15B, 17B). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 15–19 well-spaced, pointed teeth, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with seven well-spaced, pointed teeth, plus 10–12 vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 4: 4: 4: 4: 4: 5–6: 5–8: 4: T2T: 0. Sternal chaetotaxy IV–XII: 10: 10–11: 8–10: 8–10: 9–10: 9–10: 9: -: 2. Genital region: sternite II with 8–9 setae scattered on median area, genital opening slit-like, sternite III with 16–18 setae (Fig. 15F).

Legs (Fig. 17C, D): fine granulation present on anterodorsal faces of trochanter IV, femur I, IV and patella IV. Leg III: Femur 1.94–2.21 × as long as patella; tarsus 2.00–2.29 × as long as tibia. Leg IV: Femoropatella 2.67–3.29 × as long as deep; tibia 5.00–5.83 × as long as deep; with basal tactile setae on both tarsal segments: Basitarsus 2.67–3.60 × as long as deep (TS = 0.31–0.39), telotarsus 10.50–13.00 × as long as deep and 2.47–2.50 × as long as basitarsus (TS = 0.23–0.26). Setae of leg I (trochanter to tibia) 3–4: 9–10: 4–6: 6–8, setae of leg IV (trochanter to basitarsus) 2–3: 2–3: 4–6: 7–8: 5–7. Arolium not divided, slightly shorter than the simple claws.

Adult female (paratype) (Figs 14B, 15G). mostly same as males; tergal chaetotaxy I–XII: 2: 2: 4: 4: 4: 5: 5: 6: 6: 4: T2T: 0; sternal chaetotaxy IV–XII: 8: 11: 10: 10: 10: 11: 9: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 10 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: Body length 1.29–1.41. Pedipalps: trochanter 0.17–0.18/0.08–0.09 (2.00–2.12), femur 0.59–0.61/0.09–0.10 (5.90–6.78), patella 0.22–0.24/0.09–0.10 (2.30–2.67), chela 0.77–0.82/0.12–0.13 (6.31–6.75), hand 0.39–0.42/0.12–0.13 (3.23–3.25), movable chelal finger length 0.38–0.41. Chelicera 0.29–0.32/0.17 (1.71–1.88), movable finger length 0.17–0.19. Carapace 0.32–0.36/0.35–0.37 (0.91–0.97). Leg I: trochanter 0.11–0.12/0.07–0.09 (1.33–1.57), femur 0.31–0.35/0.07–0.09 (5.50–6.20), patella 0.14–0.17/0.04–0.05 (2.80–4.25), tibia 0.16–0.18/0.04 (4.00–4.50), tarsus 0.36–0.39/0.03–0.04 (9.75–12.67). Leg IV: trochanter 0.17–0.19/0.10–0.13 (1.31–1.72), femoropatella 0.54–0.56/0.17–0.21 (2.67–3.29), tibia 0.35–0.37/0.06–0.07 (5.00–5.83), basitarsus 0.16–0.18/0.05–0.06 (2.67–3.60), telotarsus 0.39–0.42/0.03–0.04 (10.50–13.00).

Females: body length 1.68. Pedipalps: trochanter 0.22/0.11 (2.00), femur 0.75/0.12 (6.25), patella 0.28/0.13(2.15), chela 1.04/0.20 (5.20), hand 0.55/0.12 (2.75), movable chelal finger length 0.50. Chelicera 0.41/0.24 (1.71), movable finger length 0.25. Carapace 0.40/0.47 (0.85). Leg I: trochanter 0.13/0.12 (1.08), femur 0.40/0.08 (5.00), patella 0.21/0.07 (3.00), tibia 0.21/0.06 (3.50), tarsus 0.46/0.05 (9.20). Leg IV: trochanter 0.21/0.14 (1.50), femoropatella 0.67/0.25 (2.68), tibia 0.43/0.08 (5.38), basitarsus 0.22/0.07 (3.14), telotarsus 0.51/0.05 (10.20).

Lagynochthonius houi sp. nov. differs from all other epigean species of the genus Lagynochthonius from China except L. duo sp. nov. by the following combination of characters: the presence of a triangular epistome and the presence of two setae on tergite I and II (Beier 1951, 1967; Hu and Zhang 2012a, b; Zhang and Zhang 2014).

Lagynochthonius houi sp. nov. differs from L. duo sp. nov. in the length of the movable chelal finger which is 0.95–1.05 × as long as the hand in males and 0.91 × as long as the hand in female, whereas in L. duo sp. nov. it is 1.11–1.27 × as long as the hand in males and 1.11 × as long as hand in female. Additionally, L. houi sp. nov. lacks intercalary tooth on the chelal fingers, whereas the fixed chelal finger posesses intercalary teeth in L. duo sp. nov.

China (Guizhou Province).

Holotype ♂ (Ps.-MHBU-GZ2022070201): China, Guizhou Province, Tongren City, Yinjiang County, 500 m near Sanhua Mountain, under topsoil and in the leaf litter layer [27°53′40.73″N, 108°32′46.16″E], 818 m a.s.l., 7 July 2022, Yanmeng Hou, Lu Zhang, Nana Zhan, Jianzhou Sun & Long Lin leg. Paratypes: 2 ♂ (Ps.-MHBU-GZ2022070203 & GZ2022070205) and 2 ♀ (Ps.-MHBU-GZ2022070202 & GZ2022070204), all with the same data as the holotype.

Named after the Sanhua Mountain, near the type locality. A noun in apposition.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome hump-shaped; tergites I–IV each with four setae. Rallum with seven blades. Pedipalps slender, chela 6.80–7.89 (♂), 5.31–5.40 (♀) × as long as broad; femur 6.50–6.63 (♂), 5.70–6.00 (♀) × as long as broad; chelal fingers without intercalary teeth, fixed chelal finger with a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Males (holotype and paratypes) (Figs 18A, 19A–F, 20, 21).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker.

Cephalothorax (Figs 19D, 20A): carapace nearly subquadrate, 0.92–0.97 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrate; epistome small and hump-shaped; four eyes, anterior pair of eyes well-developed, posterior pair with flat lenses; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 9–11 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 20D); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 19C, 20B): almost as long as carapace, 1.81–1.93 × as long as broad; five setae and three lyrifissures (including an exterior condylar lyrifissure, an exterior lyrifissure and extra lyrifissure (near sub basal setae)) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 14–18 teeth, distal one largest; movable finger with 16–18 retrorse contiguous small teeth; galea completely vestigial (Fig. 20B). Serrula exterior with 19–20 and serrula interior with 10–12 blades. Rallum with seven blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 20C).

Pedipalp (Figs 19A, B, E, 20E, 21A, B): trochanter 1.88–2.14, femur 6.50–6.75, patella 2.22–2.50, chela 6.80–7.89, hand 3.20–3.67 × as long as broad; femur 2.57–2.65 × as long as patella; movable chelal finger 1.15–1.19 × as long as hand and 0.53–0.56 × as long as chela. Setae generally long and acuminate. Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist at base of fixed chelal finger; esb and eb at almost the same level and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, very close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b and close to it (Figs 19A, 21A). Fixed chelal finger with sensilla af_1–2 close together, near tip; movable chelal finger with four sensilla: am_1–2 near tip, p₂ slightly distad of sb, p₁ proximad of sb and very close to chelal teeth (Fig. 21A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 19B, 21B). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 18 or 19 well-spaced, pointed teeth, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with six well-spaced, pointed teeth, plus 8–10 vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4–6: 4–6: 5–6: 6: 4: T2T: 0. Sternal chaetotaxy IV–XII: 10–12: 10–11: 11–13: 9–13: 10–12: 10–12: 9: -: 2. Genital region: sternite II with ten setae scattered on median area, genital opening slit-like, sternite III with 16–18 setae (Fig. 19F).

Legs (Fig. 21C, D): fine granulation present on anterodorsal faces of trochanter IV, femur I; scale-like texture display on anterodorsal faces of femoropatella IV. Leg I: femur 2.57–2.65 × as long as patella; tarsus 2.07–2.28 × as long as tibia. Leg IV: femoropatella 2.67–3.00 × as long as deep; tibia 4.43–5.33 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.50–3.50 × as long as deep (TS = 0.36–0.43), telotarsus 8.75–11.67 × as long as deep and 2.33–2.36 × as long as basitarsus (TS = 0.21–0.23). Setae of leg I (trochanter to tibia) 3–4: 7–8: 3–6: 6–9, setae of leg IV (trochanter to basitarsus) 2–3: 3–5: 5–6: 7–8: 5–7. Arolium not divided, slightly shorter than the simple claws.

Adult females (paratypes) (Figs 18B, 19G). Mostly same as males; tergal chaetotaxy I–XII: 4: 4: 4: 4: 4–6: 6: 5–6: 6: 6: 4: T2T: 0; sternal chaetotaxy IV–XII: 12–13: 13–15: 11–13: 11–12: 12: 11: 9–10: -: 2. Genital region: sternite II with ten setae scattered on median area, sternite III with a row of 10–12 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.30–1.36. Pedipalps: trochanter 0.15/0.07–0.08 (1.88–2.14), femur 0.52–0.54/0.08 (6.50–6.63), patella 0.20–0.21/0.08–0.09 (2.22–2.50), chela 0.68–0.73/0.09–0.10 (6.80–7.89), hand 0.32–0.34/0.09–0.10 (3.20–3.67), movable chelal finger length 0.38–0.41. Chelicera 0.29–0.30/0.15–0.16 (1.81–1.93), movable finger length 0.18–0.19. Carapace 0.32–0.36/0.35–0.37 (0.91–0.97). Leg I: trochanter 0.09–0.11/0.08–0.09 (1.00–1.22), femur 0.27–0.28/0.05 (5.40–5.60), patella 0.13–0.15/0.05–0.06 (2.33–3.00), tibia 0.14–0.15/0.04–0.05 (2.80–3.75), tarsus 0.30–0.32/0.03 (10.00–10.67). Leg IV: trochanter 0.13–0.16/0.10–0.11 (1.30–1.45), femoropatella 0.46–0.48/0.16–0.18 (2.67–3.00), tibia 0.31–0.32/0.06–0.07 (4.43–5.33), basitarsus 0.14–0.15/0.04–0.06 (2.50–3.50), telotarsus 0.33–0.35/0.03–0.04 (8.75–11.67).

Females: body length 1.61–1.71. Pedipalps: trochanter 0.15–0.19/0.08–0.09 (1.67–2.38), femur 0.57–0.60/0.10 (5.70–6.00), patella 0.25–0.26/0.11 (2.27–2.36), chela 0.81–0.85/0.15–0.16 (5.2), hand 0.39–0.41/0.15–0.16 (2.75), movable chelal finger length 0.43–0.45. Chelicera 0.34–0.37/0.19–0.21 (1.76–1.79), movable finger length 0.22–0.23. Carapace 0.35–0.36/0.34–0.37 (0.82–0.88). Leg I: trochanter 0.09–0.13/0.09 (1.33–1.44), femur 0.30–0.32/0.06–0.08 (3.75–5.33), patella 0.17–0.18/0.05–0.06 (2.83–3.60), tibia 0.16–0.17/0.04–0.05 (3.20–4.25), tarsus 0.34–0.35/0.04 (8.50–8.75). Leg IV: trochanter 0.15–0.19/0.10–0.12 (1.50–1.58), femoropatella 0.49–0.54/0.21 (2.33–2.57), tibia 0.35–0.36/0.07 (5.00–5.14), basitarsus 0.15–0.16/0.06–0.07 (2.29–2.50), telotarsus 0.36–0.38/0.03–0.04 (9.50–12.00).

Lagynochthonius sanhuaensis sp. nov. most closely resembles L. niger in the absence of intercalary teeth and the presence of four setae on tergites I and II, but differs from it in several characters. First, the new species has a shorter (0.68–0.73 mm compared to 0.75–0.93 mm in L. niger) and thinner chela (6.80–7.89 × as long as broad compared to 5.17–6.25 × as long as broad in L. niger) in males. Second, the shape of the epistome is hump-shaped in L. sanhuaensis sp. nov., whereas it is triangular in L. niger. Third, the rallum has seven blades in L. sanhuaensis sp. nov., whereas it has eight blades in L. niger (Hu and Zhang 2012a).

China (Guizhou Province).