Tyrannochthonius xiannvyanensis sp. nov.

urn:lsid:zoobank.org:act: 732B6785-C1B6-4F71-B9D1-526839238FCB

Figs 1J, 35–39

Diagnosis

(♂ ♀) Moderately sized troglomorphic species with elongated appendages; four eyes, anterior pair of eyes reduced, posterior pair of eyespots; anterior margin of carapace thin, finely denticulated, epistome small, rounded and obtuse; posterior margin of carapace with 2 setae; tergites I–IV each with four setae. Pedipalps slender, femur 6.53–6.80 (♂), 6.75–7.27 (♀) × as long as broad, length 0.98–1.02 (♂), 1.08–1.09 (♀); chela 7.21–7.33 (♂), 6.77–6.91 (♀) × as long as broad, length 1.32–1.37 (♂), 1.45–1.49 (♀); both chelal fingers with intercalary teeth; sb midway between st and b.

Etymology

Named after the type locality, Xiannvyan Cave.

Vernacular name

仙kƌ伪$.

Type material

Holotype

CHINA • ♂; Guangxi, Hechi City, Yizhou District, Qingyuan Town, Yankou Village, Xiannvyan Cave; 24.488011° N, 108.567428° E; 150 m a.s.l.; 4 Oct. 2019; Zegang Feng and Lingchen Zhao leg.; MHBU, Ps.- MHBU-GX2019100401.

Paratypes

CHINA • 1 ♂, 2 ♀♀; same data as for holotype; MHBU, Ps.- MHBU-GX2019100402–04.

Description

Adult male (Figs 35–39)

COLOR. Generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker black, soft parts pale.

CEPHALOTHORAX (Figs 36D, 37A). Carapace nearly subquadrate, 1.04 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin slightly serrate; epistome small, rounded and obtuse; four eyes, anterior pair of eyes reduced, posterior pair of eyespots; with 18 setae arranged s4s: 4: 4: 2: 2, most setae acuminate, sturdy, long and gently curved, anterolateral setae much shorter than others; with three pairs of lyrifissures, first and second pair situated middle and flank to the setae of ocular row, third pair situated lateral to sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta more than ½ as long as medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 12 terminally indented coxal spines on each side, set as an oblique and arched row, central spines slightly longer than others (Fig. 37D); intercoxal tubercle absent; chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

CHELICERA (Figs 36C, 37B). Almost as long as carapace, 1.79–1.86 × 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 hand with 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 10–15 contiguous small teeth; galea completely vestigial (Fig. 36C). Serrula exterior with 20–22 and serrula interior with 12–13 blades. Rallum with eight blades, distal one longest, with fine barbules and slightly set apart from other blades, latter tightly grouped and with long pinnae, some of which subdivided (Fig. 37C).

PEDIPALP (Figs 36A–B, F, 37E, 38A–B). Trochanter 1.63–1.81, femur 6.53–6.80, patella 2.29–2.69, chela 7.21–7.33, hand 2.50–2.68 × as long as broad; femur 2.37–2.51 × as long as patella; movable chelal finger 1.71–1.93 × as long as hand and 0.64–0.65 × as long as chela. Setae generally long and acuminate. Chelal hand not constricted towards fingers, apodeme complex of movable chelal finger slightly 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 slightly distal eb and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, slightly close to chelal teeth; dx situated distal to et; sb midway between st and b; b and t situated subdistally, it slightly distal to t and t distal to est; est slightly distal to b (Figs 36A, 38A). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 36B, 38B). Both chelal fingers with row of teeth, spaced regularly along margin, teeth smaller distally and proximally: fixed finger with 30–34 well-spaced, slightly retrorse and pointed teeth and 25– 26 intercalary microdenticles; movable finger with 20–24 almost contiguous, slightly retrorse and pointed teeth, plus 9– 14 intercalary microdenticles and 6–10 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: 4–5: 5–6: 5–6: 4–6: T2T: 0. Sternal chaetotaxy IV–XII: 12: 8–10:6–8: 6–8: 7–9:9: 9: -:2. Genital region: sternite II with 9–10 setae scattered on median area, genital opening slit-like, sternite III with row of 14–16 setae (Fig. 36G).

LEGS (Fig. 38C–D). Fine granulation present on anterodorsal faces of femur IV and patella IV. Leg I: femur 1.93–2.00 × as long as patella; tarsus 2.25–2.32 × as long as tibia. Leg IV: femoropatella 2.79– 2.90 × as long as deep; tibia 5.27–5.36 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.67–2.78 × as long as deep (TS = 0.24–0.33), telotarsus 10.83–13.00 × as long as deep and 2.60–2.71 × as long as basitarsus (TS = 0.18–0.23). Setae of leg I (trochanter to tibia) 3: 10–11: 7–8: 8–10, setae of leg IV (trochanter to basitarsus) 1–2: 3: 6: 8–9: 8–9. Arolium not divided, slightly shorter than simple claws.

Adult females (paratypes; Figs 35B, 36H)

Mostly same as males; tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4: 4: 5: 6: 4: T2T: 0; sternal chaetotaxy IV–XII: 10–12: 10–11: 6–8: 8–9: 9–10: 9–10: 9: -:2. Genital region: sternite II with 10 setae scattered on median area, sternite III with row of 12 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses)

Males

Body length 1.85–2.13. Pedipalps: trochanter 0.26–0.29/0.16 (1.63–1.81), femur 0.98–1.02/0.15 (6.53– 6.80), patella 0.39–0.43/0.16–0.17 (2.29–2.69), chela 1.32–1.37/0.18–0.19 (7.21–7.33), hand 0.45– 0.51/0.18–0.19 (2.50–2.68), movable chelal finger length 0.87. Chelicera 0.52–0.54/0.29 (1.79–1.86), movable finger length 0.30. Carapace 0.58–0.59/0.56–0.57 (1.04). Leg I: trochanter 0.18–0.21/0.14–0.15 (1.29–1.40), femur 0.52–0.56/0.09 (5.78–6.22), patella 0.26–0.29/0.07–0.08 (3.63–3.71), tibia 0.25– 0.28/0.06 (4.17–4.67), tarsus 0.58–0.63/0.05–0.06 (10.50–11.60). Leg IV: trochanter 0.26–0.27/0.16– 0.18 (1.44–1.69), femoropatella 0.81–0.90/0.29–0.31 (2.79–2.90), tibia 0.58–0.59/0.11 (5.27–5.36), basitarsus 0.24–0.25/0.09 (2.67–2.78), telotarsus 0.65/0.05–0.06 (10.83–13.00).

Females

Body length 1.90–2.26. Pedipalps: trochanter 0.29–0.32/0.17 (1.71–1.88), femur 1.08–1.09/0.15–0.16 (6.75–7.27), patella 0.43–0.45/0.18–0.19 (2.37–2.39), chela 1.45–1.49/0.21–0.22 (6.77–6.91), hand 0.53–0.59/0.21–0.22 (2.52–2.68), movable chelal finger length 0.92–0.94. Chelicera 0.59–0.61/0.30– 0.32 (1.84–2.03), movable finger length 0.30–0.31. Carapace 0.63–0.64/0.60–0.61 (1.03–1.07). Leg I: trochanter 0.21–0.22/0.16 (1.32–1.38), femur 0.55–0.56/0.10 (5.50–5.60), patella 0.28–0.29/0.08 (3.50– 3.63), tibia 0.28–0.29/0.07 (4.00–4.14), tarsus 0.63–0.65/0.06 (10.50–10.83). Leg IV: trochanter 0.27– 0.28/0.17–0.18 (1.5–1.65), femoropatella 0.90–0.92/0.30–0.31 (2.96–3.00), tibia 0.53–0.60/0.10–0.12 (5.00–5.30), basitarsus 0.27/0.09 (3.00), telotarsus 0.67–0.68/0.05–0.06 (11.33–13.40).

Remarks

Tyrannochthonius xiannvyanensis sp. nov. most closely resembles T. fenghuangensis sp. nov. in the position of trichobothrium sb (sb midway between st and b), the shape of epistome (small, rounded and obtuse) and carapace with four eyes, anterior pair of eyes reduced, posterior pair of eyespots, but differs in several characters as follows: longer and thinner pedipalpal chela (length 1.32–1.37 mm (♂), 1.45–1.49 mm (♀), 7.21–7.33 (♂), 6.77–6.91 (♀) × as long as broad compared to length 0.79 mm (♂), 0.82–0.83 mm (♀), 6.08 (♂), 5.13–5.19 (♀) × as long as broad in T. fenghuangensis) and longer and thinner pedipalpal femur (length 0.98–1.02 mm (♂), 1.08–1.09 (♀), 6.53–6.80 (♂), 6.75–7.27 (♀) × as long as broad compared to length 0.54 mm (♂), 0.55–0.58 mm (♀), 5.40 (♂), 4.83–5.50 (♀) × as long as broad in T. fenghuangensis).

Distribution

Known only from the type locality, Xiannvyan Cave (Guangxi, China).