Allochthonius xinqiaoensis, Gao & Hou & Zhang, 2023

Gao, Zhizhong, Hou, Yanmeng & Zhang, Feng, 2023, Four new species of cave-adapted pseudoscorpions (Pseudoscorpiones, Pseudotyrannochthoniidae) from Guizhou, China, ZooKeys 1139, pp. 33-69 : 33

Allochthonius xinqiaoensis sp. nov.

Figs 1D , 13 , 14 , 15 , 16 , 17 Chinese name 新桥异伪蝎

Type material.

Holotype: China • ♀; Guizhou Province, Fenggang County, Heba Town, Xinqiao Village, Sanjie Cave; 27°54.23'N, 107°47.80'E; 828 m a.s.l.; 26 Jul. 2019; Zegang Feng, Zhaoyi Li and Chen Zhang leg.; under a stone in the deep zone; Ps.-MHBU-GZC190726 (Figs 1D , 13 ).

Diagnosis

(♀). The new species can be recognized by the following combination of characters: each cheliceral finger with several small basal teeth between large teeth, most of which appear in pairs, the fingertips blunt, not sharp; rallum with eight blades (each with fine pinnate, the basal-most blade shorter than the others); pedipalps slender, femur 9.71, chela 5.44 × longer than broad, both chelal fingers with a row of teeth (each chelal finger with 23 teeth), slightly retrorse and pointed.

Etymology.

Named after the village of Xinqiao, near the type locality.

Description.

Adult female (male unknown) (Figs 14 - 17 ). Color (Figs 14 , 15 ): generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale. Cephalothorax (Figs 15B, D , 16A, C ): carapace inverted trapezoid, 1.00 × longer than broad, gently narrowed posteriorly; surface smooth, without furrows but with seven lyrifissures and the posterior part with squamous sculpturing; no traces of eyes; epistomal process absent, space between median setae slightly recurved; with 14 setae arranged 4: 4: 2: 2: 2, preocular setae absent, most setae heavy, long and gently curved. Chaetotaxy of coxae: P 3, I 6, II 7-9, III 5, IV 5; manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; coxal spines present on coxa I only, consisting of a tubercle expanded terminally into a characteristic “spray” or “fan” of six elevated processes which extend apically, subequal in length (Figs 15D , 16C ); bisetose intercoxal tubercle present between coxae III and IV (Fig. 15D ). Chelicera (Figs 15C , 16B, E ): large, approximately as long as carapace, 2.38 × longer than broad; five setae present on hand, all setae acuminate, ventrobasal seta shorter than others; movable finger with a medial seta; exterior condylar lyrifissure and exterior lyrifissure exist, palm with five extra (surrounding an accessory seta). Cheliceral palm with moderate hispid granulation on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with nine acute teeth, distal one largest; movable finger with a slight bump apical tooth and 12 retrorse contiguous teeth of equal length, each finger with several small basal teeth between large teeth, most of which appear in pairs, four on movable finger and six on fixed finger; the fingertips blunt, not sharp; galea represented by a very slight bump on movable finger. Serrula exterior with 17 blades and serrula interior with ten blades. Rallum in two rows and composed of eight blades with fine pinnate, of which the basal-most blade shorter than the others (Fig. 16E ). Pedipalp (Figs 15A , 16D , 17A, B ): long and slender, trochanter 1.63, femur 9.71, patella 2.83, chela 5.44, hand 2.25 × longer than broad; femur 2.67 × longer than patella; movable chelal finger 1.44 × longer than hand and 0.60 × longer than chela. Setae generally long and acuminate; two distal lyrifissures present on patella, femur with one (Fig. 16D ). Chelal palm robust and slightly constricted towards fingers. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib, isb, eb, esb, and ist clustered at the base of fixed finger, ist slightly distal to esb; it slightly distal to est, situated subdistally; et situated subdistally, very close to chelal teeth; dx situated distal to et, near the tip of fixed finger; sb situated closer to b than to st (Fig. 17A ). Microsetae (chemosensory setae) absent on hand and both palpal fingers. Sensilla absent. Both chelal fingers with a row of teeth, homodentate, spaced regularly along the margin, larger and well-spaced teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 23 teeth, slightly retrorse and pointed; movable chelal finger with 23 teeth (slightly smaller than teeth on fixed chelal finger) and a tubercle between the eleventh and twelfth teeth (Fig. 17A ). Chelal fingers markedly curved in dorsal view (Fig. 17B ). Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I-XII: 3: 4: 4: 6: 6: 6: 6: 7: 5: 4: TT: 0; tergites VIII and IX each with an unpaired median seta; a lyrifissure on each side of tergites I-IX. Sternal chaetotaxy IV-XII: 9: 12: 11: 12: 12: 9: 8: 0: 2. Anterior genital operculum with six setae plus 12 setae on posterior margin, with a pair of lyrifissures present anterolateral and posteriolateral to genital opening, respectively (Fig. 15E ). Legs (Fig. 17C, D ): generally typical, long, and slender. Fine granulation present on anterodorsal faces of femur IV and patella IV. Femur of leg I 1.61 × longer than patella and with one lyrifissure at the base of femur; tarsus 2.24 × longer than tibia. Femoropatella of leg IV 4.74 × longer than deep and with one lyrifissure at the base of femur; tibia 6.58 × longer than deep; with basal tactile setae on both tarsal segments: basitarsus 4.44 × longer than deep (TS = 0.28), telotarsus 14.29 × longer than deep and 2.50 × longer than basitarsus (TS = 0.20). Setae of leg I (trochanter to tibia) 2: 12: 11: 19, setae of leg IV (trochanter to basitarsus) 3: 2: 6: 24: 14. Arolium slightly shorter than the claws, not divided; claws simple. Dimensions of female holotype (length/breadth or, in the case of the legs, length/depth in mm): body length 2.01. Pedipalps: trochanter 0.31/0.19, femur 1.36/0.14, patella 0.51/0.18, chela 1.74/0.32, hand 0.72/0.32, movable finger length 1.04. Chelicera 0.57/0.24, movable finger length 0.32. Carapace 0.55/0.55. Leg I: trochanter 0.22/0.17, femur 0.79/0.10, patella 0.49/0.09, tibia 0.38/0.07, tarsus 0.85/0.06. Leg IV: trochanter 0.34/0.19, femoropatella 1.09/0.23, tibia 0.79/0.12, basitarsus 0.40/0.09, telotarsus 1.00/0.07.

Remarks.

Allochthonius xinqiaoensis sp. nov. is similar to A. ishikawai shiragatakiensis Morikawa, 1954 in having a pair of distinctly curved chelal fingers, but differs by the presence of lower number of rallum blades (8 vs. 10), larger body size (body length 2.01 vs. 1.75 mm) and more chelal fingers teeth (23 vs. 9 on the fixed chelal finger and 23 vs. 11 on the movable chelal finger).

Allochthonius xinqiaoensis sp. nov. can be distinguished from A. pandus sp. nov. by the presence of more blades of coxal spines (6 vs. 4), lower number of rallum blades (8 vs. 9), thicker chela (chela 5.44 (♀) × vs. 6.64-7.15 (♀) × longer than broad), more setae on the coxae (3: 6: 7-9: 5: 5 vs. 3: 4: 5: 5: 5) and lower number of teeth on the chelal fingers (23 vs. 31-33 teeth on the fixed chelal finger and 23 vs. 26-28 teeth on the movable chelal finger); Allochthonius xinqiaoensis sp. nov. can be distinguished from A. bainiensis sp. nov. by the presence a pair of distinctly curved chelal fingers.

Allochthonius xinqiaoensis sp. nov. differs from A. brevitus and A. yoshizawai in the number of setae on the anterior of the carapace (4 vs. 6) and the cheliceral hand (5 vs. 6), and the number of rallum blades (8 vs. 11).

Allochthonius xinqiaoensis sp. nov. can be distinguished from A. ishikawai and all the other A. ishikawai subspecies by the number of setae on the carapace (14 vs. 16 or more), the presence of lower number of rallum blades (8 vs. 10) and more teeth on both chelal fingers (23 vs. 11-17 teeth on the movable chelal finger and 23 vs. 9-17 teeth on the fixed chelal finger).

Allochthonius xinqiaoensis sp. nov. can be distinguished from the other species of Allochthonius by the absence of any traces of eyes ( Morikawa 1954, 1956, 1960; Hu and Zhang 2012; Viana and Ferreira 2021; WPC 2022).

Distribution and habitat.

This species is only known from the type locality, Sanjie Cave (Figs 1D , 13 ), which is located ~ 1.8 km northeast of Xinqiao Village (Fenggang County). This limestone cave has a small oval entrance (~ 1 m high and 2 m wide), ~ 200 meters in length, with a large, elongated exit at the end of the cave (~ 5 m high and 50 m wide). The interior entirety of the cave is large, inclined and extending downwards. The cave ground was covered with stones. The specimen was collected under a stone ~ 100 m from the cave entrance.

Figures

Figure 1. Study area with indication of cave locations representing the type localities. Each color represents an administrative region (red: Guizhou Province; purple: Weining County; green: Xishui County; blue: Fenggang County) A Wulibei Cave (Spelaeochthonius wulibeiensis sp. nov.) B Liangfeng Cave (Allochthonius bainiensis sp. nov.) C Daozuo Cave (A. pandus sp. nov.) D Sanjie Cave (A. xinqiaoensis sp. nov.).

Figure 13. Sanjie Cave, type locality of Allochthonius xinqiaoensis sp. nov. A entrance B inside the cave entrance C area where A. xinqiaoensis sp. nov. specimen was collected D, E exit.

Figure 14. Allochthonius xinqiaoensis sp. nov., holotype female, habitus (minus left chelicera, pedipalp, legs I and IV, dorsal view). Scale bar: 0.50 mm.

Figure 15. Allochthonius xinqiaoensis sp. nov., holotype female A left chela (lateral view) B carapace (dorsal view) C left chelicera (dorsal view) D coxae (ventral view) E female genital area (ventral view). Scale bars: 0.20 mm (A, D); 0.10 mm (B, C, E).

Figure 16. Allochthonius xinqiaoensis sp. nov., holotype female A carapace (dorsal view), two broken ocular row setae are shown as dashed lines B left chelicera (dorsal view), with details of teeth C coxal spines on coxae I (ventral view) D left pedipalp (minus chela, dorsal view) E rallum. Scale bars: 0.20 mm (A, B, D); 0.10 mm (C, E).

Figure 17. Allochthonius xinqiaoensis sp. nov., holotype female A left chela (lateral view), with details of teeth and trichobothrial pattern B left chela (dorsal view) C leg I (lateral view) D leg IV (lateral view). Scale bars: 0.20 mm.