Tyrannochthonius rudongyanensis, Sun & Guo & Zhang, 2025

Tyrannochthonius rudongyanensis sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Type material.

Holotype • ♂ (Ps. - MHBU -GX 2019101001 ): China, Guangxi, Guilin City, Xingan County, Rudongyan Cave [25.574192 ° N, 110.620256 ° E], 240 m a. s. l., 10 October 2019, Zegang Feng & Lingchen Zhao leg. GoogleMaps Paratypes • 2 ♀ (Ps. - MHBU -GX 2019101002 –03) all with the same data as the holotype GoogleMaps • 3 ♀ (Ps. - MHBU -GX 2023020401 –03), Rudongyan Cave [25.570469 ° N, 110.627489 ° E], 213 m a. s. l., 04 February 2023, Xiangbo Guo, Jianzhou Sun, Tao Zheng & Songtao Shi leg. GoogleMaps

Etymology.

Named after the type locality, Rudongyan Cave.

Diagnosis.

(♂ ♀) Moderately sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome distinctly pointed, triangular; posterior margin of carapace with 2 setae; tergites I – IV each with four setae. Pedipalps slender, femur 6.29 (♂), 6.20–7.33 (♀) times longer than broad, length 0.88 (♂), 0.88–0.93 (♀); chela 7.23 (♂), 6.50–6.73 (♀) times longer than broad, length 1.23 (♂), 1.20–1.30 (♀); both chelal fingers with intercalary teeth; sb closer to b than st.

Description.

Adult male (Figs 2 View Figure 2 – 4 View Figure 4 ).

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

Cephalothorax (Figs 3 D View Figure 3 , 4 D View Figure 4 ): carapace nearly subquadrate, 1.00 times as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin slightly serrate; epistome triangular, without eyes or eyespots; with 18 setae arranged s 4 s: 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 the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta more than 1 / 2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 12–13 terminally indented coxal spines on each side, set as an oblique and arched row, central spines slightly longer than the others (Fig. 4 F View Figure 4 ); intercoxal tubercle absent; chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 3 C View Figure 3 , 4 C View Figure 4 ): almost as long as carapace, 2.04 times 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 14 teeth, distal one largest; movable finger with 13 contiguous small teeth; galea completely vestigial (Fig. 4 C View Figure 4 ). Serrula exterior with 22 and serrula interior with 15 blades. Rallum with eight blades, the distal one longest, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 4 E View Figure 4 ).

Pedipalp (Figs 3 A, B, E View Figure 3 , 4 A, B, G View Figure 4 ): trochanter 1.79, femur 6.29, patella 2.13, chela 7.23, hand 2.71 times as long as broad; femur 2.59 times as long as patella; movable chelal finger 1.72 times as long as hand and 0.64 times 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 slightly closer to b than to st; b and t situated subdistally, t slightly distal to it and distal to b; est situated proximal to b and close to it (Figs 3 A View Figure 3 , 4 A View Figure 4 ). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 3 B View Figure 3 , 4 B View Figure 4 ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 32 well-spaced, strongly pointed teeth and 28 intercalary microdenticles; movable finger with 18 well-spaced, strongly pointed teeth, plus 18 intercalary microdenticles and 11 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: 4: T 2 T: 0. Sternal chaetotaxy IV – XII: 12: 9: 7: 7: 7: 7: 7: -: 2. Genital region: sternite II with 11 setae scattered on median area, genital opening slit-like, sternite III with a row of 16 setae (Fig. 3 F View Figure 3 ).

Legs (Fig. 4 H – I View Figure 4 ): fine granulation present on anterodorsal faces of femur IV and patella IV. Leg I: femur 1.89 times as long as patella; tarsus 2.21 times as long as tibia. Leg IV: femoropatella 4.00 times as long as deep; tibia 5.90 times as long as deep; with basal tactile setae on both tarsal segments: basitarsus 3.57 times as long as deep (TS = 0.40), telotarsus 13.00 times as long as deep and 2.60 times as long as basitarsus (TS = 0.38). Setae of leg I (trochanter to tibia) 3: 12: 8: 10, setae of leg IV (trochanter to basitarsus) 1: 3: 6: 11: 9. Arolium not divided, slightly shorter than the simple claws.

Adult females (paratypes) (Figs 2 B View Figure 2 , 3 G View Figure 3 ). Mostly same as males; tergal chaetotaxy I – XII: 4: 4: 4: 4: 4: 4: 4: 4–5: 4–5: 4–5: T 2 T: 0; sternal chaetotaxy IV – XII: 12–14: 10: 9–10: 9: 9: 8–10: 7: -: 2. Genital region: sternite II with 9–10 setae scattered on median area, sternite III with a row of six setae.

Dimensions (length / breadth or, in the case of the legs, length / depth in mm; ratios in parentheses). Male: body length 1.88. Pedipalps: trochanter 0.25 / 0.14 (1.79), femur 0.88 / 0.14 (6.29), patella 0.34 / 0.16 (2.13), chela 1.23 / 0.17 (7.23), hand 0.46 / 0.17 (2.71), movable chelal finger length 0.79. Chelicera 0.49 / 0.24 (2.04), movable finger length 0.28. Carapace 0.54 / 0.54 (1.00). Leg I: trochanter 0.16 / 0.12 (1.33), femur 0.51 / 0.07 (7.29), patella 0.27 / 0.07 (3.86), tibia 0.24 / 0.06 (4.00), tarsus 0.53 / 0.05 (10.06). Leg IV: trochanter 0.23 / 0.14 (1.64), femoropatella 0.84 / 0.21 (4.00), tibia 0.59 / 0.10 (5.90), basitarsus 0.25 / 0.07 (3.57), telotarsus 0.65 / 0.05 (13.00).

Females: body length 1.73–1.84. Pedipalps: trochanter 0.25–0.27 / 0.15 – 0.16 (1.67–1.69), femur 0.88–0.93 / 0.12 – 0.15 (6.20–7.33), patella 0.34–0.37 / 0.15 – 0.18 (2.05–2.27), chela 1.20–1.30 / 0.18 – 0.20 (6.50–6.73), hand 0.46–0.50 / 0.18 – 0.20 (2.50–2.58), movable chelal finger length 0.77–0.83. Chelicera 0.54–0.61 / 0.25 – 0.27 (2.16–2.26), movable finger length 0.27–0.31. Carapace 0.55–0.58 / 0.54 – 0.58 (1.00–1.05). Leg I: trochanter 0.16–0.17 / 0.10 – 0.13 (1.31–1.60), femur 0.51–0.53 / 0.07 – 0.08 (6.50–7.57), patella 0.27–0.30 / 0.07 (3.86–4.29), tibia 0.23–0.25 / 0.06 (3.83–4.17), tarsus 0.53–0.56 / 0.05 (10.60–11.20). Leg IV: trochanter 0.20–0.24 / 0.11 – 0.16 (1.44–1.82), femoropatella 0.79–0.87 / 0.21 (3.36–3.76), tibia 0.56–0.60 / 0.09 – 0.10 (5.80–6.22), basitarsus 0.23–0.25 / 0.07 – 0.08 (3.00–3.29), telotarsus 0.62–0.67 / 0.05 (12.40–13.40).

Ecology.

All the specimens were collected under clod and rocks inside the cave (Fig. 5 View Figure 5 ).

Distribution.

Known only from the type locality (Guangxi Zhuang Autonomous Region, China).