Stenohya bicornuta, Guo, Zang & Fe. Zhang, 2019

Guo, Xiangbo, Zang, Xiao & Zhang, Feng, 2019, Two New Stenohya Species (Pseudoscorpiones: Neobisiidae) From The Gaoligong Mountains, Southwestern China, Acta Zoologica Academiae Scientiarum Hungaricae 65 (2), pp. 95-105 : 100-104

Stenohya bicornuta sp. n.

( Figs 4–6)

Type material. Holotype male (Ps.- MHBU-YN14040201 ), China: Yunnan Province, Baoshan City, Gaoligong Mountains (25°17’N, 98°45’E), alt. 2681 m, 2 April 2014, leg: Tian Lu . Paratypes: one male and one female (Ps.-MHBU- YN14040202–03), collected with holotype .

Etymology. The specific name is derived from the Latin word “ bicornuta ”, meaning “two horns”, referring to the shape of the projection on the chelal hand of male which is located on medial surface near base of chelal finger and has two hornlike bulges at the top.

Diagnosis. Carapace with 4 well-developed eyes, epistome triangular; apex of pedipalpal coxa with 8 long setae; male chelal hand with a projection on medial surface near base of finger, and this projection with two hornlike bulges at the top; movable chelal finger enlarged at the base (female chelal hand without projection, movable finger not enlarged at the base).

Description of males ( Fig. 4a) – Colour almost brown, abdomen darker, legs yellowish. Setae of body straight and acicular.

Carapace ( Figs 5a, 6b). Entirely smooth, 1.22–1.25 times longer than broad, with a total of 24 setae, including 6 near anterior margin and 6 near posterior margin; with one pair lyrifissures near the anterior eyes; epistome short and triangular in shape, with rounded apex; with 4 corneate eyes.

Chelicera ( Figs 5b, 6e). Hand with 7 setae and 2 lyrifissures, movable finger with 1 seta situated sub-medially; fixed finger with 12–13 teeth; movable finger with 7 teeth; serrula exterior with 37–40 lamellae; serrula interior with 35–36 lamellae; galea ( Fig. 5d) divided into 2 main branches, each branch secondarily divided to 3 rami; rallum consisting of 8 blades, all with anteriorly-directed spinules, the basalmost blade shortest ( Fig. 5c).

Pedipalps ( Figs 5f, 5g, 6a, 6c, 6d). Apex of pedipalpal coxa rounded, with 8 long setae. Femur and patella with several tubercles prolaterally; chela smooth; chelal hand with a projection on medial surface near base of finger, and this projection with two hornlike bulges at the top; movable finger enlarged at the base; trochanter 1.53–1.91, femur 5.27–5.87, patella 4.00–4.29, chela (with pedicel) 4.36–4.79, chela (without pedicel) 4.11–4.56 times longer than broad, movable finger 1.56–1.64 times longer than hand (with pedicel); fixed chelal finger with 8, movable finger with 4 trichobothria: eb, esb, ib and isb located basally, et, est and it situated distally, ist closer to est -et -ist than to isb -ib -esb -eb in fixed chelal finger; trichobothria t and st in distal fourth, b and sb in basal fourth of movable finger. Venom apparatus present only in fixed chelal finger, duct very short. Fixed chelal finger with 91–94 small, cusped teeth, movable finger with 72 small teeth, cusped teeth located only in distal third of the finger.

Abdomen. Pleural membrane granulated. Tergites and sternites undivided, tergal chaetotaxy (I–XI): 4: 8–9: 10: 11–12: 13: 13: 14–16: 14: 12: 13: 9, sternal chaetotaxy (IV–XI): 22: 26–29: 28: 28: 24: 22: 18: 8; in addition, sternites VI–VIII with 18–24 medial scattered glandular setae; sternite III with 7, sternite IV with 6 setae along anterior margin of each stigmata; anal cone with 2 dorsal and 2 ventral setae. Genital area ( Figs 5h, 6f): sternite II with total of 43–44 setae and 2 lyrifissures; sternite III with 21–23 setae and 2 lyrifissures anteriorly, 20 setae on posterior margin. Genitalia with 10 setae on posterior genital plate.

Legs. Leg I ( Fig. 6i) and leg IV ( Figs 5j, 6j) typical. Tibia IV with a sub-medial tactile seta (TS = 0.64–0.67), basitarsus IV with 3 tactile setae situated basally, medially and chela, lateral view; b = carapace, dorsal view; c = right chelal hand and the base of movable finger, ventral view (showing the chelal hand projection); d = right pedipalp, dorsal view; e = right chelicera, dorsal view; f = genital area; g = genital area; h = right pedipalp, dorsal view; i = right leg I, lateral view; j = right leg IV, lateral view distally (TS = 0.14, 0.56–0.60, 0.84–0.89), telotarsus IV with 2 tactile setae (TS = 0.40, 0.68). Subterminal tarsal seta with 4 branches; arolium not divided, shorter than the slender, simple claws.

Description of female ( Fig. 4b) – As in holotype, except where noted.

Chelicera. Fixed finger with 14 teeth; movable finger with 7 teeth; serrula exterior with 37 lamellae; serrula interior with 33 lamellae; galea with 7 terminal rami ( Fig. 5e).

Pedipalps ( Fig. 5h). Femur, patella and chela entirely smooth; chelal hand without projection, movable chelal finger of normal size at base; trochanter 1.57, femur 5.37, patella 3.48, chela (with pedicel) 4.20, chela (without pedicel) 3.79 times longer than broad, movable finger 1.22 times longer than hand (with pedicel). Fixed chelal finger with 105 small, cusped teeth, movable finger with 88 small teeth, only teeth in distal third of the finger with cusp.

Abdomen. Tergal chaetotaxy (I–XI): 4: 8: 8: 12: 10: 10: 12: 11: 13: 12: 9, sternal chaetotaxy (IV–XI): 20: 27: 22: 22: 20: 17: 14: 7; sternites VI–VIII in addition with 2 medial scattered glandular setae. Genital area ( Figs 5i, 6g): sternite II with 14 setae and 2 lyrifissures; sternite III with a row of 28 setae and 2 lyrifissures along posterior margin.

Measurements (in mm; ratios in parentheses are length/breadth or, for legs, length/ depth). Male. Body length 3.75–4.14. Carapace 1.44–1.50/1.15–1.23 (1.22–1.25×). Chelicera 0.81–0.85/0.39 (2.08–2.18×), movable finger length 0.53–0.56. Pedipalpal trochanter 0.86– 0.90/0.45–0.59, femur 2.16–2.23/0.38–0.41, patella 1.92–1.93/0.45–0.48, chela (with pedicel) 3.27–3.35/0.70–0.75, chela (without pedicel) 3.08–3.19/0.70–0.75, hand (with pedicel) 1.27–1.30/0.70–0.75 (1.73–1.81×), movable finger length 1.98–2.13. Leg I: trochanter 0.40– 0.42/0.29–0.30 (1.38–1.40×), femur 1.09–1.11/0.20–0.22 (4.95–5.55×), patella 0.78–0.79/0.19– 0.20 (3.95–4.11×), tibia 0.90–0.91/0.15 (6.00–6.07×), basitarsus 0.56–0.58/0.11–0.12 (4.83– 5.09×), telotarsus 0.60–0.61/0.11–0.12 (5.08–5.45×). Leg IV: trochanter 0.69–0.72/0.26–0.28 (2.57–2.65×), femur + patella 1.91/0.34–0.37 (5.16–5.62×), tibia 1.59–1.64/0.20–0.22 (7.23– 8.20×), basitarsus 0.73–0.78/0.13–0.15 (5.20–5.62×), telotarsus 0.94–0.96/0.13 (7.23–7.38×).

Female. Body length 4.72. Carapace 1.39/1.28 (1.09×). Chelicera: 0.91/0.48 (1.90×), movable finger length 0.58. Pedipalpal trochanter 0.83/0.53, femur 2.04/0.38, patella 1.60/0.46, chela (with pedicel) 3.26/0.81, chela (without pedicel) 3.07/0.81, hand (with pedicel) 1.47/0.81 (1.81×), movable finger length 1.80. Leg I: trochanter 0.42/0.29 (1.45×), femur 1.05/0.21 (5.00×), patella 0.73/0.20 (3.65×), tibia 0.84/0.15 (5.60×), basitarsus 0.52/0.11 (4.73×), telotarsus 0.60/0.11 (5.45×). Leg IV: trochanter 0.73/0.27 (2.70×), femur + patella 1.84/0.39 (4.72×), tibia 1.51/0.22 (6.86×), basitarsus 0.72/0.13 (5.54×), telotarsus 0.93/0.13 (7.15×).

Distribution. China (Yunnan).

Remarks. Appearance of a distinct projection on prolateral face of the chela in dorsal view has been previously described for S. hamata ( Leclerc et Mahnert, 1988) from Thailand, S. curvata and S. meiacantha from China ( LECLERC & MAHNERT 1988, ZHAO et al. 2011, YANG & ZHANG 2013). Stenohya bicornuta can be easily separated from the others by the location and shape of this peculiar projection, e.g. in S. hamata , there is a thorn-like projection near base of finger on retrolateral face of the chelal hand which is pointed distally (see LECLERC & MAHNERT 1988: Figs 4–5), in S. curvata , it is a spine-like projection on prolateral face of the chelal hand (see ZHAO et al. 2011: Figs 4, 7–8), and in S. meiacantha , the projection on chelal hand is relatively blunt and distinctly small (see YANG & ZHANG 2013: Fig. 21), while in S. bicornuta , chelal hand projection is large and almost rectangular in shape with two hornlike bulges at the top.