Allochthonius lini, 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 : 50-53

Allochthonius lini sp. nov.

urn:lsid:zoobank.org:act:A63F930C-B176-411F-8254-6B843FF240F7

Figs 1 , 4A–B

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 basal and subapical tooth, rallum with 11 blades (each with fine barbules, the basal-most blade shorter than the others); and 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 (♂) 5.56–5.59 ×, (♀) 4.95–4.98 × as long as broad, length (♂) 0.89–0.92 mm, (♀) 0.99–1.01 mm; chela (♂) 4.78–4.81 ×, (♀) 4.44–4.50 × as long as broad, length (♂) 1.29–1.31 mm, (♀) 1.51–1.54 mm; ratio movable chelal finger/chelal hand (♂) 1.78–1.82 ×, (♀) 0.97–0.99 ×.

Etymology

The specific epithet was given in honour of Dr Yu-Chen Lin (College of Life Science, Sichuan University, China), not only due to the assistance provided during fieldwork, but also for his great contribution to the knowledge of arthropods, especially Mysmenidae .

Type material

Holotype CHINA • ♂; Yunnan Province, Zhaotong City, Zhenxiong County, Wude Town , Xinzhai Village , Xiaoguoquan Cave ; 25.586027° N, 104.762101° E; 1220 m a.s.l.; 9 Apr. 2017; Yun-Chun Li leg.; MCWNU ( Ar-Ps-YN-0082 ).

Paratypes CHINA • 9 ♂♂, 9 ♀♀; same collection data as for holotype; MCWNU ( Ar-Ps-YN-0027 ) • 3 ♂♂, 3 ♀♀; same collection data as for preceding; 30 Aug. 2020; Yun-Chun Li, Yu-Chen Lin, Ya Li and Yun-Fei Shu leg.; MCWNU ( Ar-Ps-YN-0019 ) .

Description

Adult male

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

CARAPACE ( Fig. 1A ). 0.81–0.85 × as long as broad, scarcely constricted posteriorly, with 4 welldeveloped eyes; epistome absent, space between median setae slightly recurved. Carapace surface with 4 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, all setae acuminate, movable finger with 1 seta in medial position, with 1 small lyrifissure in most dorsal row of setae on hand, galea absent. Fixed finger with 5 conspicuous teeth, including 1 large basal tooth and 1 subapical tooth; movable finger with 17–19 teeth ( Fig. 1B ). Serrula exterior with 21–24 lamellae; serrula interior with 16–18 lamellae. Rallum composed of 11 blades with fine barbules, basal-most 1 distinctly shorter than others ( Fig. 1D ).

PEDIPALP ( Fig. 1G–I ). All setae acuminate. Trochanter 1.47–1.51 ×, femur 5.56–5.59 ×, patella 2.19– 2.24 × as long as broad, femur 2.54–2.60 × as long as patella. Chela 4.78–4.81 × and hand 1.70–1.77 × as long as broad; movable chelal finger 1.78–1.82 × as long as hand. Fixed finger with 17 acute teeth, including 1 large basal tooth, almost close to junction; movable finger with 16 teeth, tubercle between 9 and 10. 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 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 sligthly longer than distance between b and t.

ABDOMEN. Tergal chaetotaxy (I–XII): 4: 6: 8: 9: 11: 12: 12: 13: 10: 6: 2: 0; sternal chaetotaxy (IV–XII): 18: 18: 16: 18: 16: 13: 7: 0: 2. Manducatory process with 2 setae. Pedipalpal coxa with 3 setae, coxa I 4, II 5, III 5–6, IV 6–7 setae; intercoxal tubercle present with 2 setae ( Fig. 1J ). Coxal blades only present on coxa I, with spray of 8 clavate blades ( Fig. 1C ). Anterior genital operculum with 8 setae and 2 lyrifissures; genital opening with 15 setae on the right side, and 12 on the left ( Fig. 1K ).

LEGS ( Fig. 1E–F ). Leg I: trochanter 1.20–1.21 × as long as deep, femur 4.17–4.22 × as long as deep and 1.72–1.75 × as long as patella, patella 2.90–2.93 × as long as deep, tibia 3.63–3.65 × as long as deep, tarsus 9.33–9.40 × as long as deep. Leg IV: trochanter 1.56–1.58 × as long as deep, femur +patella 3.14–3.20 × as long as deep, femur shorter than patella, tibia 5.18–5.23 × as long as deep, metatarsus 3.25–3.29 × as long as deep, tarsus 9.67–9.70 × as long as deep. Metatarsus with 1 tactile seta (subbasal, TS = 0.21), tarsus with 2 tactile setae (sub-basal, TS = 0.19; subterminal, TS = 0.17). Arolia shorter than claws, latter slender and smooth.

Adult female

Mostly the same as the holotype.

CARAPACE. 0.80–0.85 × as long as broad.

PEDIPALP. Trochanter 1.20–1.24 × as long as broad, femur 4.95–4.98 × as long as broad, patella 2.00– 2.07 × as long as broad, femur 2.48–2.51 × as long as patella. Chela 4.44–4.50 × as long as broad, hand 1.62–1.65 × as long as broad; movable finger 1.76–1.81 × as long as hand.

ABDOMEN. Tergal chaetotaxy (I–XII): 4: 6: 7: 11: 11: 11: 12: 14: 9: 6: 2: 0; sternal chaetotaxy (IV– XII): 18: 17: 16: 16: 14: 12: 8: 0: 2. Genital opening slit-like, anterior genital operculum with 10 setae, without lyrifissures ( Fig. 1L ).

DIMENSIONS (length/width or, in the case of the legs, length/depth in mm). Males (females in parentheses). Body length 2.72–2.81 (2.81–2.93). Carapace 0.48–0.51/0.59–0.61 (0.53–0.58/0.66– 0.70). Pedipalp: trochanter 0.25–0.26/0.17–0.18 (0.24–0.26/0.20–0.22), femur 0.89–0.92/0.16–0.19 (0.99–1.01/0.20–0.21), patella 0.35–0.37/0.16–0.18 (0.40–0.44/0.20–0.21), hand 0.46–0.48/0.27–0.28 (0.55–0.59/0.34–0.36), length of movable chelal finger 0.82–0.84 (0.97–0.99), chela 1.29–1.31/0.27– 0.28 (1.51–1.54/0.34–0.36). Leg I: trochanter 0.18–0.19/0.15–0.17 (0.22–0.24/0.19–0.20), femur 0.50–0.54/0.12–0.13 (0.55–0.57/0.11–0.12), patella 0.29–0.31/0.10–0.11 (0.34–0.37/0.10–0.11), tibia 0.29–0.31/0.08–0.10 (0.32–0.34/0.08–0.09), tarsus 0.56–0.58/0.06–0.07 (0.62–0.65/0.07–0.08). Leg IV: trochanter 0.25–0.28/0.16–0.18 (0.20–0.22/0.18–0.19), femur +patella 0.69–0.72/0.22–0.23 (0.78–0.82/0.24–0.26), tibia 0.57–0.59/0.11–0.12 (0.66–0.69/0.12–0.13), metatarsus 0.26–0.28/0.08– 0.09 (0.29–0.31/0.10–0.11), tarsus 0.58–0.61/0.06–0.07 (0.67–0.69/0.07–0.08).

Distribution

China (Yunnan).

Habitat

The cave was 10–80 m high, 300 m long and 50–200 m wide. The new species were collected from under the wet and dimly lit gravel 10–50 m away from the cave entrance. In addition, some spiders and Carabidae were also collected in the area.

Figures

Fig. 1. Allochthonius lini sp. nov. A–K. ♂, holotype (MCWNU (Ar-Ps-YN-0082)). L. ♀, paratype (MCWNU (Ar-Ps-YN-0019)). A. Carapace. B. Right chelicera. C. Coxal spines. D. Rallum of left chelicera. E. Right leg I, lateral view. F. Right leg IV, lateral view. G. Right pedipalp (minus chela). H. Chela, retrolateral view. I. Chela, dorsal view. J. Intercoxal tubercle. K. Male genital area. L. 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.