Lagynochthonius daidaiensis, Hou & Feng & Zhang, 2023

Hou, Yanmeng, Feng, Zegang & Zhang, Feng, 2023, Three new species of cave-adapted pseudoscorpions (Pseudoscorpiones, Chthoniidae) from eastern Yunnan, China, ZooKeys 1153, pp. 73-95 : 73

Lagynochthonius daidaiensis sp. nov.

Figs 10 , 11 , 12 , 13 Chinese name: 呆呆拉伪蝎

Type material.

Holotype: China • ♀; Yunnan Province, Qiubei County, Shuanglongying Town, Pingtan Village, Daidai Cave; 24°19.772'N, 104°14.355'E; 1228 m a.s.l.; 20 Jul. 2021; Zegang Feng, Hongru Xu, Liu Fu and Nana Zhan leg.; under a stone in the dark zone; Ps.-MHBU-HBUARA#2021-176-01 (Figs 1A , 10 ). Paratypes: • 2 ♀; the same data as the holotype; Ps.-MSWU-HBUARA#2021-176-02-HBUARA#2021-176-03.

Diagnosis

(♀). Moderately sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome pointed and small, triangular; posterior margin of carapace with two setae; tergites I-IV each with two setae. Pedipalps slender, femur 7.79-8.07 × longer than broad; chela 7.67-8.39 × longer than deep; both chelal fingers without intercalary teeth but fixed chelal finger with a modified accessory tooth (td) on dorso-antiaxial face.

Etymology.

Named after the type locality, Daidai Cave.

Description.

Adult females (male unknown) (Figs 10C , 11 - 13 ). Color: generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale. Cephalothorax (Figs 12C , 13A, C ): carapace 0.97 × longer than broad, gently narrowed posteriorly; surface smooth, without furrows; no traces of eyes; anterior margin slightly serrate; epistome pointed and small, triangular; with 18 setae arranged s4s:4:4:2:2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with three pairs of lyrifissures, the first two pairs situated middle and lateral to the setae of ocular row respectively, the third situated exterior to the sole pair of setae of posterior row. Chaetotaxy of coxae: P 3, I 3, II 3-4, III 5, IV 5; manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with small, rounded anteromedial process; coxae II with 11 or 12 terminally indented coxal spines on each side, set as an oblique and arc row, longer spines present in the middle of the row, becoming shorter distally and proximally and incised for ca. half their length (Fig. 13C ); intercoxal tubercle absent; without sub-oral seta. Chelicera (Figs 12D , 13B, D ): large, ca. as long as carapace, 2.41 × longer than broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal seta shorter than others; movable finger with one medial seta. Cheliceral palm with moderate hispid granulation on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 15-17 teeth, distal one largest; movable finger with 12 retrorse contiguous small teeth; galea absent (Fig. 13B ). Serrula exterior with 21 blades and serrula interior with 13 or 14 blades. Rallum with seven blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided (Fig. 13D ). Pedipalp (Figs 12A, B, F , 13E-G ): long and slender, trochanter 1.25-1.41, femur 7.79-8.07, patella 2.35-2.53, chela 7.67-8.39, hand 3.29-3.61 × longer than broad; femur 2.83-2.87 × longer than patella; movable chelal finger 1.32-1.35 × longer than hand and 0.57-0.58 × longer than chela. Setae generally long and acuminate; one distal lyrifissure present on patella (Figs 12F , 13E ). Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized, with weak granulation dorsally at base of fixed chelal finger. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb, and ist forming an oblique row at base of fixed chelal finger; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, very close to chelal teeth; dx situated distal to et; sb situated midway between b and st; b and t situated subdistally, t situated distal to b; est and it situated between b and t (Fig. 13F ). A tiny antiaxial lyrifissure present at base of fixed chelal finger (situated distal to ist). Both chelal fingers with a row of teeth, homodentate, spaced regularly along the margin, larger teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 35 or 36 macrodenticles, slightly retrorse and pointed, plus a modified accessory tooth on dorso-antiaxial face (td, close to dx), 36 or 37 in total; movable chelal finger with 20-22 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus nine or ten vestigial, rounded and contiguous basal teeth, 30 or 31 in total (Fig. 13F ). Chelal fingers slightly curved in dorsal view; microsetae (sc) present on dorsum of chelal hand (Figs 12B , 13G ). Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I-XII: 2:2:2:2:4:4-5:4-5:5:5:4:T2T:0, tergites VIII and IX each with an unpaired median seta. Sternal chaetotaxy IV-XII: 11-12:7-8:7:7-8:7-8:7:7-8:0:2. Anterior genital operculum with 10 setae, posterior margin with 13-14 marginal setae, 23-24 in total (Fig. 12E ). Legs (Fig. 13H, I ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur IV and patella IV. Femur of leg I 1.88-1.97 × longer than patella and with one lyrifissure at the base of femur; tarsus 2.72-2.73 × longer than tibia. Femoropatella of leg IV 4.00 × longer than deep; tibia 6.20-6.33 × longer than deep; with basal tactile setae on both tarsal segments: basitarsus 3.50-3.71 × longer than deep (TS = 0.29-0.35), telotarsus 14.60-15.20 × longer than deep and 2.71-2.81 × longer than basitarsus (TS = 0.36). Arolium slightly shorter than the claws, not divided; claws simple. Dimensions of adult females (length/breadth or, in the case of the legs, also for chela and hand, length/depth in mm): body length 1.85-2.04. Pedipalps: trochanter 0.20-0.24/0.16-0.17, femur 1.09-1.13/0.14, patella 0.38-0.40/0.15-0.17, chela 1.51-1.61/0.18-0.21, hand 0.65-0.69/0.18-0.21, movable chelal finger length 0.86-0.93. Chelicera 0.65-0.70/0.27-0.29, movable finger length 0.34-0.36. Carapace 0.56-0.58/0.58-0.60. Leg I: trochanter 0.16-0.18/0.15, femur 0.60-0.65/0.08, patella 0.32-0.33/0.07, tibia 0.25-0.26/0.05-0.06, tarsus 0.68-0.71/0.05. Leg IV: trochanter 0.25-0.26/0.15, femoropatella 0.84-0.92/0.21-0.23, tibia 0.57-0.62/0.09-0.10, basitarsus 0.26-0.28/0.07-0.08, telotarsus 0.73-0.76/0.05.

Remarks.

Lagynochthonius daidaiensis sp. nov. is similar to L. laoxueyanensis Hou, Gao & Zhang, 2022 (from Yunnan, China), but differs by the number of setae on tergites III-IV (2 vs. 4), a shorter chela (chela 7.67-8.39 vs. 6.88-7.22 (♀) × longer than deep, length 1.51-1.61 vs. 1.65-1.66 mm) and the number of coxal spines blades (11 or 12 vs. 9) ( Hou et al. 2022a).

Lagynochthonius daidaiensis sp. nov. can be easily distinguished from L. fengi Hou, Gao & Zhang, 2022, L. retrorsus Hou, Gao & Zhang, 2022, L. serratus Hou, Gao & Zhang, 2022, L. spinulentus Hou, Gao & Zhang, 2022, L. xiaolinensis Hou, Gao & Zhang, 2022 and L. yaowangguensis Hou, Gao & Zhang, 2022 by the absence of intercalary teeth on both chelal fingers; from L. crassus Hou, Gao & Zhang, 2022 by lacking a pair of anterior eyespots; from L. magnidentatus Hou, Gao & Zhang, 2022 and L. xinjiaoensis Hou, Gao & Zhang, 2022 by the presence of two carapaceal antero-median setae; from L. bailongtanensis Li, Liu & Shi, 2019, L. minimus Hou, Gao & Zhang, 2022 and L. xibaiensis Hou, Gao & Zhang, 2022 by the number of setae on tergites I-II (2 vs. 3-4) ( Li et al. 2019; Hou et al. 2022b).

Distribution.

Known only from the type locality.

Figures

Figure 1. Study area, general cave locations, and type locality for each species, Yunnan Province, China. Each color represents an administrative region (green: Yunnan Province; red: Fuyuan County) A Daidai Cave (Lagynochthonius daidaiensis sp. nov.) B Xianren Cave (Tyrannochthonius capito sp. nov.) C, D unnamed cave and Dongtianfu Cave (T. calvatus sp. nov.).

Figure 10. Daidai Cave (type locality), habitat of Lagynochthonius daidaiensis sp. nov. A entrance B inside the cave entrance C live female of L. daidaiensis sp. nov. in its natural environment.

Figure 11. Lagynochthonius daidaiensis sp. nov., holotype female, habitus (dorsal view). Scale bar: 0.50 mm.

Figure 12. Lagynochthonius daidaiensis sp. nov., holotype female A left chela (lateral view) B left chela (dorsal view) C carapace (dorsal view) D left chelicera (dorsal view) E female genital area (ventral view) F left pedipalp (minus chela, dorsal view). Scale bars: 0.20 mm (A, B, F); 0.10 mm (C-E).

Figure 13. Lagynochthonius daidaiensis sp. nov., holotype female A carapace (dorsal view) B left chelicera (dorsal view) with details of dentation C coxal spines on coxae II (ventral view) D rallum E left pedipalp (minus chela, dorsal view) F left chela (lateral view) with details of dentation and trichobothrial pattern G left chela (dorsal view) H leg I (lateral view) I leg IV (lateral view). Scale bars: 0.20 mm (A, B, E-I); 0.10 mm (C, D).