Allochthonius xuae, Yun-Chun LI, 2023

Yun-Chun LI, 2023, Three new species of pseudoscorpions (Arachnida: Pseudoscorpiones: Pseudotyrannochthoniidae) from caves in Yunnan and Guizhou Provinces, China, European Journal of Taxonomy 861, pp. 48-64 : 53-56

Allochthonius xuae sp. nov.

urn:lsid:zoobank.org:act:C70C86D8-8E61-4684-AEE2-DA6EBE7D5171

Figs 2 , 4C–D

Diagnosis

Differs from the other members of the genus Allochthonius by the following combination of characters: cheliceral hand with 7 setae, fixed cheliceral finger with large subapical tooth, rallum with 11 blades (each with fine barbules, the basal-most blade shorter than the others); coxae I with 8 tridentate blades, each blade with a central spine terminally distinctly expanded as fan-shaped, all situated on a common tubercle. Pedipalpal femur (♂) 5.21 ×, (♀) 5.59–5.61 × as long as broad, length (♂) 0.99 mm, (♀) 1.23– 1.24 mm; chela (♂) 4.81 ×, (♀) 4.20–4.24 × as long as broad, length (♂) 1.49 mm, (♀) 1.72–1.78 mm; ratio movable chelal finger/chelal hand (♂) 1.63 ×, (♀) 1.63–1.65 ×.

Etymology

The specific epithet was given in honour of Mrs Juan Xu, the wife of the author.

Type material

Holotype CHINA • ♂; Guizhou Province, Dafang County, Wenge Town, Sanhe Village , Yelaoda Cave ; 27º10.900′ N, 105º28.278′ E; 1438 m a.s.l.; 23 Apr. 2019; Yun-Chun Li leg.; MCWNU ( Ar-Ps-GZ-0056 ).

Paratypes CHINA • 5 ♀♀; same collection data as for holotype; MCWNU ( Ar-Ps-GZ-0012 ) .

Description

Adult male

COLOURS. Chelicerae and pedipalps reddish brown, remaining parts brown; carapace, chelicerae and abdomen with dense round white spots.

CARAPACE ( Fig. 2A ). 0.87 × as long as broad, scarcely constricted posteriorly, with 4 well-developed eyes; epistome absent, space between median setae slightly recurved. Carapace surface with 5 lyrifissures, near anterior and posterior margins. With 26 setae arranged 10: 4: 6: 2: 4.

CHELICERA. Relatively broad. Cuticle of hand gently granulate to squamate. Hand with 7 setae and 3 lyrifissures, all setae acuminate, movable finger with 1 seta in medial position, galea absent. Fixed finger with 4 conspicuous teeth, including 1 large subapical tooth, distinctly larger than others; movable finger with 21–23 teeth ( Fig. 2B ). Serrula exterior with 23–24 lamellae; serrula interior with 19–20

lamellae. Rallum composed of 11 blades with fine barbules, the apical-most one with 3 small branches at bend and basal-most 1 distinctly shorter than others ( Fig. 2D ).

PEDIPALP ( Fig. 2E–G ). All setae acuminate. Trochanter 1.47 ×, femur 5.21 ×, patella 2.47 × as long as broad, femur 2.36 × as long as patella. Chela 4.81 ×, hand 1.81 × as long as broad; movable chelal finger 1.63 × as long as hand. Fixed finger with 20 acute teeth, which middle ones larger than that in both ends; movable finger with 16 teeth, tubercle between 8 and 9. Fixed chelal finger with 8 trichobothria and movable finger with 4, eb, esb, ib, isb, and ist located basally of fixed finger and 2 special sensory hairs (xs) near the fingertip; on movable finger, st subproximal and in medial position on finger, triplet sb, b, and t distomedial to distal, distance between sb and b distinctly longer than distance between b and t.

ABDOMEN. Tergal chaetotaxy (I–XII): 4: 5: 7: 7: 8: 11: 11: 12: 10: 8: 2: 0; sternal chaetotaxy (IV–XII): 17: 16: 15: 16: 16: 12: 12: 0: 2. Manducatory process with 2 setae. Pedipalpal coxa with 3 setae, coxa I 5–6, II 5, III 7, IV 7 setae; intercoxal tubercle present with 2 setae. Coxal blades only present on coxa I, with spray of 8 clavate blades ( Fig. 2C ). Anterior genital operculum with 8 setae, without lyrifissures; genital opening with 14 setae on the right side, and 12 on the left ( Fig. 2H ).

LEGS. Leg I: trochanter 1.16 × as long as deep, femur 5.09 × as long as deep and 1.60 × as long as patella, patella 3.50 × as long as deep, tibia 4.57 × as long as deep, tarsus 9.43 × as long as deep. Leg IV: trochanter 0.90 × as long as deep, femur+patella 3.28 × as long as deep, femur shorter than patella, tibia 4.86 × as long as deep, metatarsus 3.67 × as long as deep, tarsus 11.33 × as long as deep. Metatarsus with 1 tactile seta (sub-basal, TS = 0.28), tarsus with 2 tactile setae (sub-basal, TS = 0.29; subterminal, TS = 0.20). Arolia shorter than claws, latter slender and smooth.

Adult female

Mostly the same as the holotype.

CARAPACE. 0.83–0.87 × as long as broad.

PEDIPALP. Trochanter 1.43–1.44 × as long as broad, femur 5.59–5.61 × as long as broad, patella 2.23– 2.25 × as long as broad, femur 2.51–2.54 × as long as patella. Chela 4.20–4.24 × as long as broad, hand 1.59–1.62 × as long as broad; movable finger 1.63–1.65 × as long as hand.

ABDOMEN. Tergal chaetotaxy (I–XII): 4: 5: 7: 9: 11: 11: 10: 14: 11: 10: 2: 0; sternal chaetotaxy (IV–XII): 18: 18: 16: 15: 16: 14: 12: 0: 2. Genital opening slit-like, anterior genital operculum with 17 setae, with 2 lyrifissures ( Fig. 2I ).

DIMENSIONS (length/width or, in the case of the legs, length/depth in mm). Male (females in parentheses): body length 2.92 (3.70–3.77). Carapace 0.52/0.60 (0.58–0.61/0.70–0.72). Pedipalp: trochanter 0.22/0.15 (0.30–0.32/0.21–0.23), femur 0.99/0.19 (1.23–1.24/0.22–0.23), patella 0.42/0.17 (0.49–0.51/0.22–0.23), hand 0.56/0.31 (0.65–0.67/0.41–0.44), length of movable chelal finger 0.91 (1.06–1.10), chela 1.49/0.31 (1.72–1.78/0.41–0.44). Leg I: trochanter 0.22/0.19 (0.20–0.22/0.16–0.18), femur 0.56/0.11 (0.64– 0.67/0.13–0.14), patella 0.35/0.10 (0.41–0.44/0.12–0.13), tibia 0.32/0.07 (0.39–0.41/0.09–0.10), tarsus 0.66/0.07 (0.73–0.75/0.08–0.09). Leg IV: trochanter 0.19/0.21 (0.32–0.34/0.25–0.26), femur+patella 0.82/0.25 (0.91–0.95/0.31–0.33), tibia 0.68/0.14 (0.76–0.79/0.17–0.19), metatarsus 0.33/0.09 (0.37– 0.39/0.11–0.12), tarsus 0.68/0.06 (0. 69–0.70/0.08–0.09).

Distribution

China (Guizhou).

Habitat

The cave was about 20–200 m high, the length was unknown, and the width was about 50– 200 m. The new species were collected from under wet, dimly lit rubble about 100 m from the cave entrance. The surrounding herbs were abundant, and some spiders, millipedes and Carabidae were also collected.

Figures

Fig. 2. Allochthonius xuae sp. nov. A–H. ♂, holotype (MCWNU (Ar-Ps-GZ-0056)). I. ♀, paratype (MCWNU (Ar-Ps-GZ-0012)). A. Carapace. B. Right chelicera. C. Coxal spines. D. Rallum of left chelicera. E. Left pedipalp (minus chela). F. Chela, retrolateral view. G. Chela, dorsal view. H. Male genital area. I. Female genital area. Scale bars = 0.20 mm.

Fig. 4. A–B. Allochthonius lini sp. nov., dorsal views. A. ♂, holotype (MCWNU (Ar-Ps-YN-0082)). B. ♀, paratype (MCWNU (Ar-Ps-YN-0019)). C–D. A. xuae sp. nov., dorsal views. C. ♂, holotype (MCWNU (Ar-Ps-GZ-0056)). D. ♀, paratype (MCWNU (Ar-Ps-GZ-0012)). Scale bar = 1.00 mm.