Parobisium tiani, Feng & Wynne & Zhang, 2020

Feng, Zegang, Wynne, J. Judson & Zhang, Feng, 2020, Cave-dwelling pseudoscorpions of China with descriptions of four new hypogean species of Parobisium (Pseudoscorpiones, Neobisiidae) from Guizhou Province, Subterranean Biology 34, pp. 61-98 : 61

Parobisium tiani sp. nov. Figs 14 , 15 , 16 , 17

Type material.

Holotype male (Ps.-MHBU-GZ13070901): China, Guizhou Province, Liupanshui City, Pan County, Chengguan Town, Biyun Cave (Figs 1A , 21 ), [25°46'29.97"N, 104°38'15.81"E], 1500 m elevation, 9 July 2013, Mingyi Tian leg. Paratypes: 1 female (Ps.-MHBU-GZ13070902), same location as holotype, 09 July 2013, Mingyi Tian leg; 2 males (Ps.-MHBU-GZ19080501, GZ19080502), 2 females (Ps.-MHBU-GZ19080503, GZ19080504) same location as holotype, estimated cave deep zone, 05 August 2019, Zegang Feng, Chen Zhang leg.

Etymology.

The name is a patronym to honor Chinese cave biologist, Mingyi Tian. He provided us with his pseudoscorpion specimens and assisted in developing this study.

Distribution.

This species is known only from the type locality.

Diagnosis.

This new troglomorphic species can be easily distinguished from other members of the genus Parobisium by following combination of characters: carapace with two faint eye spots ( P. wangae has four developed eyes, P. motianense , P. qiangzhuang and P. sanlouense with four eye spots; P. magangensis , P. xiaowutaicum and P. yuantongi lacks eyes/eye spots); epistome triangular, with rounded top (small, rounded in P. motianense , P. qiangzhuang and P. sanlouense ; triangular, with rounded top in P. tiani and P. yuantongi ; rounded in P. magangensis and P. xiaowutaicum ); pedipalpal femur 5.63-5.75 times longer than wide (8.91-8.97 times in P. magangensis ; 4.66-4.90 times in P. motianense ; 3.89-4.11 times in P. qiangzhuang ; 6.50-6.59 times in P. sanlouense ; 3.60-3.65 times in P. wangae ; 4.65 times in P. xiaowutaicum ; 6.75 times in P. yuantongi ); patella 4.52-4.58 times longer than wide (7.64-7.84 times in P. magangensis ; 3.09-3.39 times in P. motianense ; 2.54-2.60 times in P. qiangzhuang ; 5.07-5.11 times in P. sanlouense ; 1.89-2.16 times in P. wangae ; 3.14 times in P. xiaowutaicum ; 5.70 times in P. yuantongi ); pedipalpal hand with granulation (smooth in P. magangensis , P. wangae and P. xiaowutaicum ; with granulation present on chelal hand in P. tiani ; with granulation present on inside lateral of femur and chelal hand in P. qiangzhuang and P. sanlouense ; with granulation present on femur, inside lateral of patella and chelal hand in P. yuantongi ); chela (with pedicel) 4.97-5.03 times longer than wide (8.67-8.69 times in P. magangensis ; 3.72-4.06 times in P. motianense ; 3.12-3.25 times in P. qiangzhuang ; 6.08-6.34 times in P. sanlouense ; 3.13-3.52 times in P. wangae ; 3.14 times in P. xiaowutaicum ; 5.70 times in P. yuantongi ); both chelal finger has 104-112 teeth (146-162 in P. magangensis ; 71-75 in P. qiangzhuang ; 57-74 in P. wangae ; 73-75 in P. xiaowutaicum ).

Description.

Male (Fig. 15A ). Carapace, chelicerae, and pedipalps reddish brown or yellowish brown; abdomen and legs yellowish or yellowish brown.

Carapace (Figs 16A , 17A ): Smooth, 1.22-1.27 times longer than broad, with a total of 24 setae, including 4 on anterior margin, 6 on posterior margin, and 1 on each side of anterior lateral margin; with 2 faint eye spots on a flat surface; epistome triangular, with rounded top.

Chelicera (Figs 16C , 17B ): Hand with 7 setae, movable finger with 1 submedial seta; fixed finger with 13-16 teeth; movable finger with 13-16 teeth; serrula exterior with 39-42 lamellae; serrula interior with 20-24 lamellae. Galea (Fig. 17D ) replaced by a small rounded transparent sclerotic knob. Rallum (Fig. 17C ) with 8 pinnate blade, distal-most blade with expanded base, and together with the second blade separated from the others, proximal one short.

Pedipalps (Figs 16E-F , 17H-I, K ): Apex of coxa rounded, with 5 setae on each side, pedipalpal coxa with 7-8 setae. Pedipalp smooth and slender except for hand, which is finely granular. Trochanter 2.67-2.70 times longer than wide, femur 5.63-5.73, patella 4.52-4.58 times longer than wide, pedicel about half the entire length of patella, chela (with pedicel) 4.97-5.03, chela (without pedicel) 4.39-4.40 times longer than wide, movable finger 1.44-1.45 times longer than hand (without pedicel). Fixed chelal finger with 8 trichobothria, movable finger with 4, eb and esb on lateral margin of hand; ib, ist and isb closely grouped at the base of the fixed finger; est slightly distal of finger middle; it closer to fingertip than et; on movable finger, st nearer to t than to sb, the latter slightly nearer st than to b (Figs 16F , 17H-I ). Venom apparatus present only in fixed chelal finger, venom duct short, not extending past half of the distance to et. Fixed chelal finger with 104-109 teeth, movable finger with 105-112 teeth.

Abdomen: Pleural membrane granulated. Tergal chaetotaxy (I-XI): 8-9/ 8-9/ 9/ 10/ 9/ 9-11/ 9-10/ 10-11/ 10-12/ 10-11/ 6-7; sternal chaetotaxy (IV-XI): 7-8/ 12-13/ 14/ 12-13/ 11-13/ 11-12/ 11-12/ 3-4; stigmata with 5-6 setae; anal cone with 2 dorsal and 2 ventral setae. Male genital area (Figs 16G , 17F ): sternite II with 34-43 scattered setae; sternite III with anteromedian groove flanked by one small seta on each side, with 15 posterior setae.

Legs: Coxa chaetotaxy (I-IV): 6-7/ 4-5/ 4-5/ 7. Leg I (Figs 16I , 17L ): femur 6.27-6.50, patella 3.54-4.23, tibia 8.87-9.08, basitarsus 3.73-3.93, telotarsus 5.07-5.85 times longer than deep, femur 1.54-1.62 times longer than patella, telotarsus 1.36-1.38 times longer than basitarsus. Leg IV (Figs 16J , 17M ): femur + patella 5.30-5.46 times longer than deep, femur shorter than patella, tibia 9.04-9.75, basitarsus 4.06-4.41, telotarsus 5.61-6.20 times longer than deep, telotarsus 1.35 times longer than basitarsus; basitarsus with a tactile setae in basally (TS=0.12-0.15), telotarsus with a tactile setae in middle (TS=0.46-0.47); subterminal tarsal seta (Fig. 17J ) bifurcate, both branches dentate; arolium not divided, shorter than the slender and simple claws.

Female (paratypes) (Fig. 15B ): Mostly same as holotype.

Chelicera. Hand with 7 setae, movable finger with 1 submedial seta; fixed finger with 13-16 teeth; movable finger with 12-19 teeth; serrula exterior with 39-41 lamellae; serrula interior with 22-23 lamellae. Galea (Fig. 17E ) replaced by a semicircular transparent sclerotic knob; rallum of 8-9 blades, similar to holotype.

Pedipalps. Trochanter 2.44-2.61, femur 5.59-5.61, patella 4.38-4.57 times longer than wide; chela (with pedicel) 4.25-4.46 times longer than wide, chela (without pedicel) 3.79-4.00 times longer than wide, movable finger 1.26-1.28 times longer than hand (without pedicel). Fixed chelal finger with 96-106 teeth, movable finger with 97-105 teeth.

Abdomen. Tergal chaetotaxy (I-XI): 6-7/ 7-9/ 8-9/ 8-10/ 9-11/ 10-12/ 9-12/ 9-12/ 11-12/ 11/ 6-7; sternal chaetotaxy (IV-XI): 8-9/ 13-15/ 13-16/ 13-15/ 13-15/ 12-13/ 12-14/ 3. Female genital area (Figs 16H , 17G ): sternite II with 3-8 setae on each side; sternite III with a row of 13-16 setae on the posterior margin.

Measurements: (length/breadth or depth in mm; ratios for most characters in parentheses). Male (holotype and paratypes). Body length 3.87-5.09. Carapace 1.22-1.27 (1.32-1.43/1.08-1.13). Pedipalpal trochanter 2.67-2.70 (1.04-1.16/0.39-0.43), femur 5.63-5.73 (2.29-2.42/0.40-0.43), patella 4.52-4.58 (2.17-2.38/0.48-0.52), chela (with pedicel) 4.97-5.03 (3.28-3.52/0.66-0.70), chela (without pedicel) 4.39-4.40 (2.90-3.08/0.66-0.70), hand length (without pedicel) 1.32-1.36, movable finger length 1.91-1.96 (1.44-1.45 times longer than hand without pedicel). Leg I: trochanter 1.35-1.50 (0.42/0.28-0.31), femur 6.27-6.50 (1.38-1.43/0.22), patella 3.54-4.23 (0.85-0.93/0.22-0.24), tibia 8.87-9.08 (1.18-1.33/0.13-0.15), basitarsus 3.73-3.93 (0.55-0.56/0.14-0.15), telotarsus 5.07-5.85 (0.76/0.13-0.15). Leg IV: trochanter 2.43-2.79 (0.68-0.78/0.28), femur + patella 5.30-5.46 (2.13-2.28/0.39-0.43), tibia 9.04-9.75 (2.17-2.34/0.24), basitarsus 4.06-4.41 (0.69-0.75/0.17), telotarsus 5.61-6.20 (0.93-1.01/0.15-0.18).

Female (paratypes). Body length 4.63-5.48. Carapace 1.19-1.27 (1.30-1.60/1.09-1.26). Pedipalpal trochanter 2.44-2.61 (0.95-1.15/0.39-0.44), femur 5.59-5.61 (2.18-2.47/0.39-0.44), patella 4.38-4.57 (2.06-2.47/0.47-0.54), chela (with pedicel) 4.25-4.46 (3.03-3.61/0.68-0.85), chela (without pedicel) 3.79-4.00 (2.72-3.22/0.68-0.85), hand length (without pedicel) 1.29-1.55, movable finger length 1.65-1.95 (1.26-1.28 times longer than hand without pedicel). Leg I: trochanter 1.47-1.60 (0.40-0.44/0.25-0.30), femur 5.39-5.92 (1.24-1.48/0.23-0.25), patella 3.75-4.18 (0.75-0.92/0.20-0.22), tibia 7.00-7.33 (1.05-1.32/0.15-0.18), basitarsus 3.14-4.07 (0.44-0.61/0.14-0.15), telotarsus 5.00-5.43 (0.65-0.76/0.13-0.14). Leg IV: trochanter 2.48-2.61 (0.67-0.81/0.27-0.31), femur + patella 5.91-5.97 (2.01-2.27/0.34-0.38), tibia 9.38-9.67 (1.97-2.32/0.21-0.24), basitarsus 3.82-4.53 (0.65-0.77/0.17), telotarsus 6.00-6.13 (0.90-0.98/0.15-0.16).

Figures

Figure 1. Study area, general cave locations, and type locality for each species, Guizhou Province, China. A Biyun Cave, Parobisium tiani sp. nov. B Zharou Cave, Parobisium qiangzhuang sp. nov. C Motian Cave, Parobisium motianense sp. nov. D Sanlou Cave, Parobisium sanlouense sp. nov.

Figure 14. Parobisium tiani sp. nov. Male habitus.

Figure 15. Parobisium tiani sp. nov. A Holotype male, dorsal view B Paratype female, dorsal view.

Figure 16. Parobisium tiani sp. nov., holotype male (A - C, E - G, I - J), female (D, H). A Carapace, dorsal view B Eye area, lateral view C Right chelicera of male, dorsal view D Right chelicera of female, dorsal view E Right pedipalp, dorsal view F Right chela, lateral view G Male genitalia H Female genitalia I Right leg I, lateral view J Right leg IV, lateral view.

Figure 17. Parobisium tiani sp. nov., holotype male (A-D, F, H-M), female (E, G). A Carapace, dorsal view B Right chelicera, dorsal view C Rallum D Movable finger of chelicera (male), showing sclerotic knob E Movable finger of chelicera (female), showing sclerotic knob F Male genitalia G Female genitalia H Right chela, dorsal view I Right chelal fingers, lateral view J Subterminal tarsal seta K Right pedipalp, dorsal view (trochanter, femur, and patella) L Right leg I, lateral view M Right leg IV, lateral view. Scale bars: 0.1 mm (C - E, J), 0.25 mm (B, F - G), 0.5 mm (A), 1 mm (H - I, K - M).

Figure 21. Biyun Cave, type locality of Parobisium tiani sp. nov. A Surrounding surface habitat with two entrances, entrance 1 (white arrow) and entrance 2 (red arrow) B Entrance 1 (white arrow) C Entrance 2 (red arrow) D Passage where specimens were collected (blue arrow).