Lagynochthonius longquanensis, Hou, Feng & Zhang, 2023

Lagynochthonius longquanensis sp. nov.

Chinese name. AEȃȗ伪Dz

Figs 36–39 View FIGURE 36 View FIGURE 37 View FIGURE 38 View FIGURE 39

Type material. Holotype ♀ (Ps.- MHBU-SC2019100601 ): China, Sichuan Province, Luzhou City, Xuyong County, Lubu Town , Longquan Cave [28.10264792°N, 105.47175407°E], 363 m a.s.l., 6 October 2019, Zegang Feng, Liu Fu, Long Hao & Jiaqi Zhao leg. GoogleMaps

Etymology. Named after the type locality, Longquan Cave.

Diagnosis. (♀). small sized hypogean species; galea slightly bump-shaped; carapace with two eyespots,anterior margin smooth; epistome absent; tergites Ⅰ–ⅠⅠ each with two setae, tergites ⅠⅠⅠ–ⅠV with four setae. Rallum with eight blades. Pedipalps slender, chela 5.50 times as long as broad; femur 5.54 times as long as broad; both chelal fingers without intercalary teeth and a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand.

Description. Adult female (holotype) ( Figs 36A View FIGURE 36 , 37 View FIGURE 37 , 38 View FIGURE 38 , 39 View FIGURE 39 ).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker black, soft parts pale.

Cephalothorax ( Figs 37D, F View FIGURE 37 , 38A View FIGURE 38 ): carapace nearly subquadrate, 0.90 times as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrations; epistome absent, with two eyespots; with 18 setae arranged s4s: 4: 4: 2: 2; with three pairs of lyrifissures, first and second pair situated middle and flank to the setae of ocular row, third pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta more than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 7 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others ( Fig. 38D View FIGURE 38 ); intercoxal tubercle absent; chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera ( Figs37C View FIGURE 37 , 38B View FIGURE 38 ): almost as long as carapace, 1.71 times as long as broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral hand with moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 12 teeth, distal one largest; movable finger with 10 retrorse contiguous small teeth; galea represented by a very slight bump on movable finger ( Fig. 37B View FIGURE 37 ). Serrula exterior with 22 and serrula interior with 13 blades. Rallum with eight 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. 38C View FIGURE 38 ).

Pedipalp ( Figs 37A–B, 37G View FIGURE 37 , 38E View FIGURE 38 , 39A–B View FIGURE 39 ): trochanter 1.90, femur 5.54, patella 2.00, chela 5.50, hand 2.25 times as long as broad; femur 2.58 times as long as patella; movable chelal finger 1.44 times as long as hand and 0.59 times as long as chela. Setae generally long and acuminate. Chelal hand gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. 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 at base of fixed chelal finger; esb slightly distal eb and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, slightly close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t slightly distal to it and distal to b; est situated distal to b and close to it ( Figs. 37A View FIGURE 37 , 39A View FIGURE 39 ). Microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs. 37B View FIGURE 37 , 39B View FIGURE 39 ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 19 well-spaced, pointed teeth, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with 11 well-spaced, pointed teeth, 7 vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 4: 4: 5: 6: 5: 6: 5: 4: T2T: 0. Sternal chaetotaxy IV– XII: 8: 10: 10: 10: 10: 10: 8: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 6 setae ( Fig. 37E View FIGURE 37 ).

Legs ( Fig. 39C–D View FIGURE 39 ): fine granulation present on anterodorsal faces of femur IV and patella IV. Leg Ⅰ: femur 1.88 times as long as patella; tarsus 2.18 times as long as tibia. Leg IV: femoropatella 2.26 times as long as deep; tibia 4.43 times as long as deep; with basal tactile setae on both tarsal segments: basitarsus 3.00 times as long as deep (TS = 0.40), telotarsus 7.25 times as long as deep and 1.93 times as long as basitarsus (TS = 0.38). Setae of leg I (trochanter to tibia) 1: 7: 6: 7, setae of leg IV (trochanter to basitarsus) 2: 1: 5: 7: 7. Arolium not divided, slightly shorter than the simple claws.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Female: body length 0.99. Pedipalps: trochanter 0.19/0.10 (1.90), femur 0.61/0.11 (5.54), patella 0.24/0.12 (2.00), chela 0.88/0.16 (5.50), hand 0.36/0.16 (2.25), movable chelal finger length 0.52. Chelicera 0.36/0.21 (1.71), movable finger length 0.21. Carapace 0.37/0.41 (0.90). Leg I: trochanter 0.11/0.07 (1.57), femur 0.30/0.06 (5.00), patella 0.16/0.05 (3.20), tibia 0.16/0.04 (4.00), tarsus 0.35/0.03 (11.67). Leg IV: trochanter 0.15/0.10 (1.50), femoropatella 0.43/0.19 (2.26), tibia 0.31/0.07 (4.43), basitarsus 0.15/0.05 (3.00), telotarsus 0.29/0.04 (7.25).

Remarks. Lagynochthonius longquanensis sp. nov. differs from all other hypogean species of the genus except L. infirmus sp. nov. by the absence of intercalary teeth on both chelal fingers, the presence of two setae on tergites Ⅰ–II and the presence of two eyespots on the carapace. It differs infirmus sp. nov. by the shorter (0.88 mm (♀) compared to 1.69–1.77 mm (♀) in L. infirmus sp. nov.) and thinner chela (5.50 (♀) times as long as broad compared to 7.75–8.13 (♀) times as long as broad in L. infirmus sp. nov.), the presence of four setae in tergite ⅠII (vs. two in L. infirmus sp. nov.), and the absence of epistome (vs. present in L. infirmus sp. nov.).

Distribution. Known only from the type locality, Longquan Cave ( China, Sichuan Province).