Tyrannochthonius dongjiensis, 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 dongjiensis sp. nov.

Figs 1 , 6A, B

Type material.

Holotype male: China, Guizhou Province, Luodian County, Dongjia Town, Dongjia Village, Nameless Cave, 25°38.53'N, 106°54.67'E, 869 m a.s.l., 7 October 2019, Yun-Chun Li leg., in MCWNU (Ar-Ps-GZ-0055). Paratypes: 2 males, 4 females, collected with the holotype, in MCWNU (Ar-Ps-GZ-0008); 5 males, 2 females, Guizhou Province, Pingtang County, Tangbian Town, Baima Cave, 25°40'6.13"N, 106°45'53.89"E, 870 m a.s.l., 6 October 2019, Yun-Chun Li leg., in MCWNU (Ar-Ps-GZ-0010).

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 six setae; epistome absent; rallum composed of six blades; tergites I-IV with two setae; apex of coxa I with long and rounded anteromedial process, near the apex with a seta; chelal hand dorsal surface with chemosensory setae; fixed chelal finger with 24 or 25 teeth, movable chelal finger with 27-29 retrorse teeth. Pedipalpal femur (♂) 7.58-7.63 ×, (♀) 7.36-7.42 × longer than broad, length (♂) 0.91-0.95 mm, (♀) 1.03-1.07 mm; chela (♂) 7.88-7.90 ×, (♀) 7.06-7.10 longer than deep, length (♂) 1.25-1.28 mm, (♀) 1.20-1.24 mm; ratio movable chelal finger/chelal hand (♂) 1.86-1.90 ×, (♀) 1.88-1.93 ×.

Etymology.

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

Description.

Adult male (Fig. 6A ).

Pale yellow-orange, chelicera slightly darker, soft parts pale (Fig. 6A ).

Carapace (Fig. 1A ): 1.26-1.30 × longer than broad, no eyes or eyespots; epistome absent; carapace surface smooth, lateral margins distinctly constricted posteriorly. With 18 setae arranged 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 with a seta (Fig. 1E ); coxae II with nine 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 (Fig. 1D ). Chelicera (Fig. 1B ): 1.82-1.85 × 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 eight or nine teeth, distal one largest, decreasing in size proximally; movable finger with 12 or 13 teeth; galea absent. Serrula exterior with 22-25 blades. Rallum composed of six blades (Fig. 1C ), 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. 1H-J ): all setae acuminate. Trochanter 1.56-1.61 ×, femur 7.58-7.63 ×, patella 2.73-2.76 × longer than broad and with three lyrifissures (Fig. 1H ). Femur 2.22-2.31 × longer than patella. Chela 7.88-7.90 ×, hand 2.63-2.66 × longer than deep; movable chelal finger 1.86-1.90 × 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. 1J ). Fixed finger with 24 or 25 teeth, middle ones larger than those at both ends; movable finger with 27-29 retrorse teeth (Fig. 1I ). 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 half-way between st and b; 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): 2: 2: 2: 2: 3-4: 4: 4: 4: 4: 2: 0; sternal chaetotaxy (IV-XII): 12: 7: 7: 7: 7: 7: 7: 0: 2. Anterior genital operculum with ten setae, genital opening slit-like, with 14 or 15 setae on the right side and 18 on the left (Fig. 1K ). Legs (Fig. 1F, G ): leg I: trochanter 1.00-1.03 ×, femur 7.63-7.66 × longer than deep and 1.91-1.97 × longer than patella; patella 4.57-4.59 ×, tibia 4.33-4.37 ×, tarsus 13.40-13.44 × longer than deep. Leg IV: trochanter 0.88-0.96 ×, femoropatella 3.83-3.87 ×, tibia 6.89-6.92 × longer than deep, basitarsus 3.75-3.80 ×longer than deep, with a basal tactile seta (TS = 0.24-0.25), telotarsus 15.2-15.5 ×longer than deep and 2.53-2.55 × longer than basitarsus, with a tactile seta near base (TS = 0.23-0.24). Arolia on legs I and IV shorter than claws.

Adult female (Fig. 6B ).

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

Carapace: slightly longer than broad (1.13-1.15 ×). Chelicera: 2.30-2.33 × longer than broad. Pedipalp: trochanter 1.80-1.86 × longer than broad, femur 7.36-7.42 × longer than broad, patella 2.63-2.70 × longer than broad, femur 2.45-2.49 × longer than patella. Chela 7.06-7.10 × longer than deep, hand 2.41-2.46 × longer than deep; movable finger 1.88-1.93 × longer than hand. Opisthosoma: tergal chaetotaxy (I-XII): 2: 2: 2: 2: 4: 4: 4: 4: 4: 2: 2: 0; sternal chaetotaxy (IV-XII): 14: 12: 8: 7: 7: 9: 7: 0: 2. Anterior genital operculum with 9 + 14 setae on posterior margin (Fig. 1L ).

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

Males (females in parentheses): body length 2.24-2.30 (2.49-2.56). Carapace 0.54-0.57/0.43-0.45 (0.53-0.55/0.47-0.48). Pedipalp: trochanter 0.25-0.28/0.16-0.18 (0.27-0.29/0.15-0.17), femur 0.91-0.95/0.12-0.14 (1.03-1.07/0.14-0.16), patella 0.41-0.44/0.15-0.17 (0.42-0.44/0.16-0.18), hand 0.42-0.45/0.16-0.17 (0.41-0.44/0.17-0.18), length of movable chelal finger 0.78-0.80 (0.77-0.79), chela 1.25-1.28/0.16-0.17 (1.20-1.24/0.17-0.18). Chelicera: 0.51-0.53/0.28-0.29 (0.53-0.55/0.23-0.24). Leg I: trochanter 0.15-0.17/0.15-0.16 (0.15-0.17/0.14-0.16), femur 0.61-0.64/0.08-0.09 (0.62-0.65/0.08-0.09), patella 0.32-0.35/0.07-0.08 (0.31-0.34/0.07-0.08), tibia 0.26-0.27/0.06-0.07 (0.27-0.29/0.06-0.07), tarsus 0.67-0.69/0.05-0.06 (0.66-0.68/0.05-0.06). Leg IV: trochanter 0.15-0.17/0.17-0.18 (0.17-0.19/0.14-0.16), femoropatella 0.88-0.92/0.23-0.25 (0.90-0.93/0.22-0.24), tibia 0.62-0.65/0.09-0.10 (0.63-0.65/0.09-0.10), basitarsus 0.30-0.32/0.08-0.09 (0.29-0.31/0.08-0.09), telotarsus 0.76-0.79/0.05-0.06 (0.79-0.82/0.06-0.07).

Distribution.

China (Guizhou).

Figures

Figure 1. Tyrannochthonius dongjiensis sp. nov., holotype male (A-K) and paratype female (L) A carapace B left chelicera C rallum of left chelicera D coxal spines E process of left coxa I, ventral view F left leg I, lateral view G left leg IV, lateral view H palp (minus chela) I chela, retrolateral view J chela, dorsal view K male genital area L female genital area. Scale bars: 0.20 mm

Figure 6. A, B Tyrannochthonius dongjiensis sp. nov., dorsal views A holotype male B paratype female C, D T. huaerensis sp. nov., dorsal views C holotype male D paratype female. Scale bar: 1.00 mm (A-D).