Tyrannochthonius hispidus, Hou & Feng & Zhang, 2023

Hou, Yanmeng, Feng, Zegang & Zhang, Feng, 2023, Diversity of cave-dwelling pseudoscorpions from Guizhou in China, with the description of twenty-four new species of the genus Tyrannochthonius (Pseudoscorpiones, Chthoniidae), Zootaxa 5262 (1), pp. 1-158 : 54-57

Tyrannochthonius hispidus sp. nov. ‹SƭƟṁae›

Figs 42–46

Type material. Holotype ♂ (Ps.-MHBU-GZJH-19-26-01): China, Guizhou Province, Jianhe County, Yangasha Sub-district, Chuandong Village , Qilin Cave , under stones within 100–300 m from the cave entrance (Temperature: 15°C, Humidity: 80%) [26°45′58.07″N, 108°27′42.06″E], 743 m a.s.l., 13 October 2019, Zegang Feng & Lingchen Zhao leg. Paratypes: 12 ♂ (Ps.-MHBU-GZJH-19-26-02–GZJH-19-26-13), 21 ♀ (Ps.-MHBU-GZJH-19-26-14–GZJH-19-26-34), all with the same data as the holotype ; 15 ♂ (Ps.- MSWU-HBUARA#2022-521 - 01 – HBUARA#2022-521-15), 12 ♀ (Ps.- MSWU-HBUARA#2022-521 - 16 –HBUARA#2022-521-27), 13 August 2022, Yanmeng Hou, Lu Zhang, Jianzhou Sun & Wenlong Fan leg., all with the same location as the holotype .

Etymology. The specific name is derived from the Latin word “ hispidus ” (= hirsute), which refers to the increased number of setae at the posterior margin of the carapace.

Diagnosis (J ♀). Moderately sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome small and pointed, triangular; posterior margin of carapace with 2–4 setae; tergites I–VI each with 4 setae. Pedipalps slender, femur 5.80–5.93 (♂), 5.93– 6.14 (♀) times longer than broad; chela 6.68–6.72 (♂), 6.20–6.79 (♀) times longer than broad; both chelal fingers with intercalary teeth.

Description. Males (holotype and paratypes) ( Figs 43A , 44A–F , 45 , 46 ).

Colour: generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.

Cephalothorax ( Figs 44C , 45A ): carapace 0.94–0.98 times longer than broad, gently narrowed posteriorly; surface smooth, without furrows; no traces of eyes; anterior margin slightly serrate; epistome small and pointed, triangular, with 2 setae flanking base; with 18–20 setae arranged s3–4s: 4: 4: 2–3: 2–4, 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, the second situated exterior to the sole pair of setae of posterior row. Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5; manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with small, rounded anteromedial process; coxae II with 7–10 terminally indented coxal spines on each side, set as an oblique row, longer spines present in the middle of the row, becoming shorter distally and proximally and incised for about half their length ( Fig. 45C ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 44D , 45B ): large, about as long as carapace, 2.29–2.30 times longer than broad; 5 setae and 2 lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal seta shorter than others; movable finger with one medial seta. Cheliceral palm with moderate hispid granulation on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 10–12 teeth, distal one largest; movable finger with 10–13 retrorse contiguous small teeth; galea completely vestigial ( Fig. 45B ). Serrula exterior with 18–20 and serrula interior with 14–15 blades. Rallum with 6 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. 45E ).

Pedipalp ( Figs 44A, B, E , 45D , 46A, B ): long and slender, trochanter 1.20–1.31, femur 5.80–5.93, patella 2.00–2.19, chela 6.68–6.72, hand 2.32–2.33 times longer than broad; femur 2.49–2.59 times longer than patella; movable chelal finger 1.77–1.83 times longer than hand and 0.61–0.64 times longer than chela. Setae generally long and acuminate; 1 distal lyrifissure present on patella ( Figs 44E , 45D ). Chelal palm not constricted towards fingers, apodeme complex of movable chelal finger only slightly sclerotized, with weak granulation dorsally at base of fixed chelal finger. Fixed chelal finger and hand with 8 trichobothria, movable chelal finger with 4 trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist forming a nearly 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 closer to st than to b; b and t situated subdistally, t situated distal to b and slightly proximal to est ( Fig. 46A ). A tiny antiaxial lyrifissure present at base of fixed chelal finger (situated distal to ist). Both chelal fingers with a row of teeth, heterodentate, spaced regularly along the margin, larger and well-spaced teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 26–28 macrodenticles, long and pointed, plus 15– 16 intercalary microdenticles, 42–43 in total; movable chelal finger with 22–24 macrodenticles (markedly smaller than teeth on fixed chelal finger), retrorse and pointed, plus 9– 10 intercalary microdenticles and 7–8 vestigial, rounded and contiguous basal teeth, 38–42 in total ( Fig. 46A ). Chelal fingers slightly curved in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs 44B , 46B ).

Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4: 4–5: 5: 5: 4: T2T: 0; tergites VIII–IX each with an unpaired median seta. Sternal chaetotaxy III–XII: 13–15: 13–14: 10: 9: 9: 9: 9–11: 9: 0: 2. Anterior genital operculum with 10 setae, genital opening slit-like, with 10–13 marginal setae on each side, 31–34 in total ( Fig. 44F ).

Legs ( Fig. 46C, D ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur IV and patella IV. Femur of leg I 1.79–1.88 times longer than patella and with 1 lyrifissure at the base of femur; tarsus 2.27–2.43 times longer than tibia. Femoropatella of leg IV 2.68–2.70 times longer than deep; tibia 5.00–5.38 times longer than deep; with basal tactile setae on both tarsal segments: metatarsus 3.14 times longer than deep (TS= 0.32), tarsus 12.50–12.75 times longer than deep and 2.27–2.32 times longer than metatarsus (TS= 0.26–0.29). Arolium slightly shorter than the claws, not divided; claws simple.

Adult females (paratypes) ( Figs 43B , 44G ). Mostly same as males, but a little larger; with same chaetotaxy of coxae as males; tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4: 4: 5: 5: 4: T2T: 0; sternal chaetotaxy IV–XII: 14: 10: 9: 9: 10: 9–10: 8–9: 0: 2; anterior genital operculum with 9–10 setae, posterior margin with 13–14 marginal setae, 23 in total; leg IV with a long tactile seta on both tarsal segments: metatarsus 3.50–3.67 times longer than deep (TS= 0.33–0.36), tarsus 10.00 times longer than deep and 2.27–2.38 times longer than metatarsus (TS= 0.32).

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.56–1.78. Pedipalps: trochanter 0.17–0.18/0.13–0.15 (1.20–1.31), femur 0.83–0.87/0.14–0.15 (5.80–5.93), patella 0.32–0.35/0.16 (2.00–2.19), chela 1.21–1.27/0.18–0.19 (6.68–6.72), hand 0.42–0.44/0.18–0.19 (2.32– 2.33), movable chelal finger length 0.77–0.78. Chelicera 0.53–0.55/0.23–0.24 (2.29–2.30), movable finger length 0.28–0.29. Carapace 0.48–0.50/0.49–0.53 (0.94–0.98). Leg I: trochanter 0.14–0.15/0.12 (1.17–1.25), femur 0.43– 0.45/0.07–0.08 (5.38–6.43), patella 0.24/0.07 (3.43), tibia 0.21–0.22/0.05–0.06 (3.50–4.40), tarsus 0.50–0.51/0.04– 0.05 (10.20–12.50). Leg IV: trochanter 0.20–0.21/0.12–0.13 (1.62–1.67), femoropatella 0.59–0.62/0.22–0.23 (2.68– 2.70), tibia 0.43–0.45/0.08–0.09 (5.00–5.38), metatarsus 0.22/0.07 (3.14), tarsus 0.50–0.51/0.07 (12.50–12.75).

Females: body length 1.77–1.99. Pedipalps: trochanter 0.18–0.20/0.14 (1.29–1.43), femur 0.86–0.89/0.14–0.15 (5.93–6.14), patella 0.35–0.36/0.16 (2.19–2.25), chela 1.24–1.29/0.19–0.20 (6.20–6.79), hand 0.44–0.45/0.19– 0.20 (2.25–2.32), movable chelal finger length 0.77–0.82. Chelicera 0.55–0.58/0.24–0.25 (2.29–2.32), movable finger length 0.29. Carapace 0.49/0.53–0.54 (0.91–0.92). Leg I: trochanter 0.12–0.15/0.12–0.13 (1.00–1.15), femur 0.44–0.45/0.07–0.08 (5.50–6.43), patella 0.24–0.26/0.07 (3.43–3.71), tibia 0.21/0.05–0.06 (2.63–3.50), tarsus 0.49–0.51/0.05 (9.80–10.20). Leg IV: trochanter 0.20/0.13 (1.54), femoropatella 0.60–0.62/0.20–0.21 (2.95–3.00), tibia 0.44–0.45/0.08–0.09 (5.00–5.50), metatarsus 0.21–0.22/0.06 (3.50–3.67), tarsus 0.50/0.05 (10.00).

Remarks. Tyrannochthonius hispidus sp. nov. is similar to T. acutus sp. nov. in having intercalary teeth on both chelal fingers and a pointed, triangular epistome, but differs by a smaller body size (body length 1.56–1.78 (J), 1.77–1.99 (♀) vs. 2.07–2.13 (J), 2.16–2.29 (♀) mm; chela 6.68–6.72 (J), 6.20–6.79 (♀) vs. 7.29–7.65 (J), 7.38–7.79 (♀) times longer than board), fewer fixed chelal finger teeth (42‒43 vs. 57‒60) and the number of blades of rallum (6 vs. 7).

Tyrannochthonius hispidus sp. nov. can be distinguished from T. chixing , T. harveyi and T. zhai by the presence of intercalary teeth on both chelal fingers, from T. akaelus and T. ganshuanensis by the number of setae on tergites I–II (4 vs. 2), from T. antridraconis by a smaller size (body length max. 1.78 mm vs. min. 1.8 mm; chela 6.68–6.72 times vs. 7.90–8.00 times longer than board, length 1.21–1.27 (J) vs. 1.70–1.76 (J) mm), more fixed chelal finger teeth (42‒43 vs. 33‒36) and the relative position of trichobothrium sb (sb closer to st than to b vs. closer to b) ( Mahnert 2009; Gao et al. 2018, 2020).

Distribution. Known only from the type locality.

Figures

FIGURE 42. Qilin Cave, type locality of Tyrannochthonius hispidus sp. nov., A. Cave location (red arrow); B. Entrance; C. Inside the cave entrance; D–E. Areas where T. hispidus sp. nov. specimens were collected (white arrow); F. Live female of T. hispidus sp. nov. in its natural environment.

FIGURE43.Tyrannochthoniushispidussp.nov.,A.Holotypemale,habitus(dorsalview);B.Paratypefemale,habitus(dorsalview).

FIGURE 44. Tyrannochthonius hispidus sp. nov., holotype male (A–F), paratype female (G): A. Left chela (lateral view); B. Left chela (dorsal view); C. Carapace (dorsal view); D. Left chelicera (dorsal view); E. Left pedipalp (minus chela, dorsal view); F. Male genital area (ventral view); G. Female genital area (ventral view).

FIGURE 45. Tyrannochthonius hispidus sp. nov., holotype male: A. Carapace (dorsal view); B. Left chelicera (dorsal view), with details of teeth; C. Coxal spines on coxae II (ventral view); D. Left pedipalp (minus chela, dorsal view); E. Rallum. Scale bars: 0.20 mm (A–B, D); 0.10 mm (C, E).

FIGURE 46. Tyrannochthonius hispidus sp. nov., holotype male: A. Left chela (lateral view), with details of teeth and with trichobothrial pattern; B. Left chela (dorsal view); C. Leg I (lateral view); D. Leg IV (lateral view). Scale bars: 0.20 mm.