Tyrannochthonius xinzhaiensis, Li, 2022

Li, Yun-Chun, 2022, Five new troglobitic species of Tyrannochthonius (Arachnida, Pseudoscorpiones, Chthoniidae) from the Yunnan, Guizhou and Sichuan Provinces, China, ZooKeys 1131, pp. 173-195 : 173

Tyrannochthonius xinzhaiensis sp. nov.

Figs 4 , 7C, D

Type material.

Holotype male: China, Yunnan Province, Zhaotong City, Zhenxiong County, Wude Town, Xinzhai Village, Daguoquan Cave, 27°35.90'N, 104°46.25'E, 1301 m a.s.l., 8 April 2017, Yun-Chun Li leg., in MCWNU (Ar-Ps-YN-0080). Paratypes: 1 male, 6 females, 6 tritonymphs, collected with the holotype, in MCWNU (Ar-Ps-YN-0007).

Diagnosis.

Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with five or six setae; epistome present; tergites V-X with four setae; coxae II with 12 terminally indented coxal spines on each side; apex of coxa I with long and rounded anteromedial process, near the apex without setae; chelal hand dorsal surface with chemosensory setae; fixed chelal finger with 26 teeth, movable chelal finger with 34 or 35 teeth. Pedipalpal femur (♂) 6.94-6.97 ×, (♀) 6.71-6.77 × longer than broad, length (♂) 1.18-1.21 mm, (♀) 1.14-1.18 mm; chela (♂) 7.90-7.91 ×, (♀) 6.44-6.42 × longer than deep, length (♂) 1.66-1.68 mm, (♀) 1.61-1.64 mm; ratio movable chelal finger/chelal hand (♂) 1.61-1.64 ×, (♀) 1.76-1.80 ×.

Etymology.

Latinized adjective, derived from the village of Xinzhai, located near the type locality.

Description.

Adult male (Fig. 7C ).

Carapace and chelicera reddish brown, remaining parts yellowish brown (Fig. 7C ).

Carapace (Fig. 4A ): 0.98-1.01 × longer than broad, no eyes or eyespots; epistome very pointed and small, triangular; carapace surface smooth, lateral margins weakly constricted posteriorly. With 17 or 18 setae arranged 5-6: 4: 4: 2: 2, anterolateral setae much shorter than others. Coxae: manducatory process pointed, with two distal setae, one long and the other slightly shorter. Pedipalpal coxa with three setae, coxa I 3, II 4, III 5, IV 5; intercoxal tubercle absent. Apex of coxa I with long and rounded anteromedial process, near the apex without setae; coxae II with 12 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 ~ ½ their length. Chelicera (Fig. 4B ): 2.59-2.61 × longer than broad, hand with five setae and one lyrifissure dorsally, movable finger with one submedial seta. Cheliceral hand with moderate hispid granulation dorsally. Fixed finger with 16 teeth, distal one largest, decreasing in size proximally; movable finger with 14 or 15 teeth; galea absent. Serrula exterior with 23 or 24 blades. Rallum composed of eight blades (Fig. 4C ), distal blade weakly recumbent basally, with fine barbules and set apart from the other blades, the latter tightly grouped and with long pinnae. Pedipalp (Fig. 4E-G ): all setae acuminate. Trochanter 1.56-1.59 ×, femur 6.94-6.97 ×, patella 1.83-1.86 × longer than broad and with four lyrifissures. Femur 2.68-2.70 × longer than patella. Chela 7.90-7.91 ×, hand 2.90-2.93 × longer than deep; movable chelal finger 1.61-1.64 × longer than hand. Chelal hand dorsal surface with a single row of five chemosensory setae between esb and ib / isb trichobothria; distal paraxial seta of hand not enlarged. Fingers straight in dorsal view (Fig. 4G ). Fixed finger with 26 teeth, middle ones larger than those at both ends; movable finger with 34 or 35 teeth (Fig. 4F ). Venom apparatus absent. Fixed chelal finger with eight trichobothria and movable finger with four, 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 nearer to tip of fixed finger; dx situated distal to et; sb near to st; b and t situated subdistally, t situated at same level as est. Opisthosoma: tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy (I-XII): 4: 4: 4: 4: 4: 4: 4: 4: 4: 4: 2: 0; sternal chaetotaxy (IV-XII): 12: 10: 10: 9: 9: 9: 7: 0: 2. Anterior genital operculum with nine setae, genital opening slit-like, with 15 or 16 marginal setae on each side (Fig. 4H ). Legs: leg I: trochanter 1.43-1.44 ×, femur 6.60-6.62 × longer than deep and 1.78-1.79 × longer than patella; patella 4.11-4.14 ×, tibia 3.88-3.92 ×, tarsus 9.57-9.60 × longer than deep. Leg IV: trochanter 1.05-1.07 ×, femoropatella 3.83-3.85 ×, tibia 5.91-5.93 × longer than deep, basitarsus 3.75-3.76 × longer than deep, with a basal tactile seta (TS = 0.20-0.21), telotarsus 12.17-12.20 × longer than deep and 2.43-2.45 × longer than basitarsus, with a tactile seta near base (TS = 0.18-0.19). Arolia on legs I and IV shorter than claws.

Adult female (Fig. 7D ).

Mostly the same as the holotype with the differences listed below.

Carapace: slightly longer than broad (1.00-1.02 ×). With 18 setae, including six on the anterior margin and two on the posterior margin. Chelicera: 2.26-2.27 × longer than broad. Pedipalp: trochanter 1.82-1.86 × longer than broad, femur 6.71-6.77 × longer than broad, patella 1.76-1.79 × longer than broad, femur 3.08-3.12 × longer than patella. Chela 6.44-6.42 × longer than deep, hand 2.20-2.22 × longer than deep; movable finger 1.76-1.80 × longer than hand. Opisthosoma: tergal chaetotaxy (I-XII): 4: 4: 3: 3: 4: 4: 4: 4: 4: 4: 2: 0; sternal chaetotaxy (IV-XII): 14: 10: 9: 9: 9: 9: 7: 0: 2. Anterior genital operculum with 9 + 6 setae on posterior margin (Fig. 4I ).

Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).

Males (females in parentheses): body length 2.76-2.85 (2.69-2.88). Carapace 0.59-0.61/0.60-0.61 (0.58-0.60/0.58-0.59). Pedipalp: trochanter 0.25-0.26/0.16-0.17 (0.31-0.34/0.17-0.19), femur 1.18-1.21/0.17-0.19 (1.14-1.18/0.17-0.19), patella 0.44-0.46/0.24-0.26 (0.37-0.40/0.21-0.23), hand 0.61-0.63/0.21-0.22 (0.55-0.58/0.25-0.26), length of movable chelal finger 0.98-1.00 (0.97-1.01), chela 1.66-1.68/0.21-0.22 (1.61-1.64/0.25-0.26). Chelicera: 0.70-0.73/0.27-0.29 (0.61-0.64/0.27-0.29). Leg I: trochanter 0.20-0.22/0.14-0.15 (0.16-0.18/0.14-0.15), femur 0.66-0.68/0.10-0.11 (0.62-0.65/0.08-0.09), patella 0.37-0.39/0.09-0.10 (0.31-0.34/0.06-0.07), tibia 0.31-0.32/0.08-0.09 (0.31-0.33/0.06-0.07), tarsus 0.67-0.69/0.07-0.08 (0.64-0.67/0.06-0.07). Leg IV: trochanter 0.21-0.23/0.20-0.21 (0.19-0.21/0.17-0.19), femoropatella 0.92-0.95/0.24-0.26 (0.83-0.86/0.22-0.24), tibia 0.65-0.67/0.11-0.12 (0.57-0.60/0.09-0.10), basitarsus 0.30-0.31/0.08-0.09 (0.27-0.29/0.07-0.08), telotarsus 0.73-0.75/0.06-0.07 (0.68-0.70/0.05-0.06).

Distribution.

China (Yunnan).

Figures

Figure 4. Tyrannochthonius xinzhaiensis sp. nov., holotype male (A-H) and paratype female (I) A carapace B right chelicera C rallum of left chelicera D process of left coxa I, ventral view E palp (minus chela) F chela, retrolateral view G chela, dorsal view H male genital area I female genital area. Scale bars: 0.20 mm.

Figure 7. A, B Tyrannochthonius huilongshanensis sp. nov., dorsal views A holotype male B paratype female C, D T. xinzhaiensis sp. nov., dorsal views C holotype male D paratype female. Scale bar: 1.00 mm (A-D).