Lagynochthonius houi, Sun & Guo & Zhang, 2024

Sun, Jianzhou, Guo, Xiangbo & Zhang, Feng, 2024, Five new epigean Lagynochthonius species (Pseudoscorpiones, Chthoniidae) from southern China, ZooKeys 1198, pp. 101-134 : 101

Lagynochthonius houi sp. nov.

Figs 14 , 15 , 16 , 17 Chinese name: 侯氏拉伪蝎

Type material.

Holotype ♂ (Ps.-MHBU-GZ2022080901): China, Guizhou Province, Qiannan Prefecture, Pintang County, Tangbian Town, Xindian Village, under topsoil and in the leaf litter layer [25°37′42.19″N, 106°43′55.15″E], 991 m a.s.l., 9 August 2022, Yanmeng Hou, Lu Zhang, Jianzhou Sun & Wenlong Fan leg. Paratypes: 2 ♂ (Ps.-MHBU-GZ2022080902-03) and 1 ♀ (Ps.-MHBU-GZ2022080904), all with the same data as the holotype.

Etymology.

This species is named for Yanmeng Hou, who participated in field work and collected some of the specimens. A noun in apposition.

Diagnosis.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome triangular; tergites I and II each with two setae, III and IV each with four setae. Rallum with eight blades. Pedipalps slender, chela 6.31-6.75 (♂), 5.20 (♀) × as long as broad; femur 5.90-6.78 (♂), 6.25 (♀) × as long as broad; chelal fingers without intercalary teeth, fixed chelal finger with a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.

Description.

Males (holotype and paratypes) (Figs 14A , 15A-F , 16 , 17 ).

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

Cephalothorax (Figs 15D , 16A ): carapace nearly subquadrate, 0.91-0.97 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other aera smooth, without furrows; anterior margin smooth, without serrate; epistome small and triangular; four eyes, anterior pair of eyes well-developed, posterior pair with flat lenses; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, second pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 9-12 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 16D ); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 15C , 16B ): almost as long as carapace, 1.71-1.88 × as long as broad; five setae and three lyrifissures (including an exterior condylar lyrifissure, an exterior lyrifissure and extra lyrifissure (near sub basal setae)) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 9-12 teeth, distal one largest; movable finger with 11-13 retrorse contiguous small teeth; galea completely vestigial (Fig. 16B ). Serrula exterior with 17-22 and serrula interior with 11-14 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. 16C ).

Pedipalp (Figs 15A, B, E , 16E , 17A, B ): trochanter 2.00-2.12, femur 5.90-6.78, patella 2.44-2.67, chela 6.31-6.75, hand 3.23-3.25 × as long as broad; femur 2.45-2.68 × as long as patella; movable chelal finger 0.95-1.05 × as long as hand and 0.49-0.51 × as long as chela. Setae generally long and acuminate. Chelal palm 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 forming a straight 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 slightly closer to st than to b; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b (Figs 15A , 17A ). Fixed chelal finger with sensilla af1-2 close together, near tip; movable chelal finger with four sensilla: am1-2 near tip, p2 slightly distad of sb, p1 distad of p2 and very close to chelal teeth (Fig. 17A ). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 15B , 17B ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 15-19 well-spaced, pointed teeth, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with seven well-spaced, pointed teeth, plus 10-12 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: 4: 4: 4: 5-6: 5-8: 4: T2T: 0. Sternal chaetotaxy IV-XII: 10: 10-11: 8-10: 8-10: 9-10: 9-10: 9: -: 2. Genital region: sternite II with 8-9 setae scattered on median area, genital opening slit-like, sternite III with 16-18 setae (Fig. 15F ).

Legs (Fig. 17C, D ): fine granulation present on anterodorsal faces of trochanter IV, femur I, IV and patella IV. Leg III: Femur 1.94-2.21 × as long as patella; tarsus 2.00-2.29 × as long as tibia. Leg IV: Femoropatella 2.67-3.29 × as long as deep; tibia 5.00-5.83 × as long as deep; with basal tactile setae on both tarsal segments: Basitarsus 2.67-3.60 × as long as deep (TS = 0.31-0.39), telotarsus 10.50-13.00 × as long as deep and 2.47-2.50 × as long as basitarsus (TS = 0.23-0.26). Setae of leg I (trochanter to tibia) 3-4: 9-10: 4-6: 6-8, setae of leg IV (trochanter to basitarsus) 2-3: 2-3: 4-6: 7-8: 5-7. Arolium not divided, slightly shorter than the simple claws.

Adult female (paratype) (Figs 14B , 15G ). mostly same as males; tergal chaetotaxy I-XII: 2: 2: 4: 4: 4: 5: 5: 6: 6: 4: T2T: 0; sternal chaetotaxy IV-XII: 8: 11: 10: 10: 10: 11: 9: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 10 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: Body length 1.29-1.41. Pedipalps: trochanter 0.17-0.18/0.08-0.09 (2.00-2.12), femur 0.59-0.61/0.09-0.10 (5.90-6.78), patella 0.22-0.24/0.09-0.10 (2.30-2.67), chela 0.77-0.82/0.12-0.13 (6.31-6.75), hand 0.39-0.42/0.12-0.13 (3.23-3.25), movable chelal finger length 0.38-0.41. Chelicera 0.29-0.32/0.17 (1.71-1.88), movable finger length 0.17-0.19. Carapace 0.32-0.36/0.35-0.37 (0.91-0.97). Leg I: trochanter 0.11-0.12/0.07-0.09 (1.33-1.57), femur 0.31-0.35/0.07-0.09 (5.50-6.20), patella 0.14-0.17/0.04-0.05 (2.80-4.25), tibia 0.16-0.18/0.04 (4.00-4.50), tarsus 0.36-0.39/0.03-0.04 (9.75-12.67). Leg IV: trochanter 0.17-0.19/0.10-0.13 (1.31-1.72), femoropatella 0.54-0.56/0.17-0.21 (2.67-3.29), tibia 0.35-0.37/0.06-0.07 (5.00-5.83), basitarsus 0.16-0.18/0.05-0.06 (2.67-3.60), telotarsus 0.39-0.42/0.03-0.04 (10.50-13.00).

Females: body length 1.68. Pedipalps: trochanter 0.22/0.11 (2.00), femur 0.75/0.12 (6.25), patella 0.28/0.13(2.15), chela 1.04/0.20 (5.20), hand 0.55/0.12 (2.75), movable chelal finger length 0.50. Chelicera 0.41/0.24 (1.71), movable finger length 0.25. Carapace 0.40/0.47 (0.85). Leg I: trochanter 0.13/0.12 (1.08), femur 0.40/0.08 (5.00), patella 0.21/0.07 (3.00), tibia 0.21/0.06 (3.50), tarsus 0.46/0.05 (9.20). Leg IV: trochanter 0.21/0.14 (1.50), femoropatella 0.67/0.25 (2.68), tibia 0.43/0.08 (5.38), basitarsus 0.22/0.07 (3.14), telotarsus 0.51/0.05 (10.20).

Remarks.

Lagynochthonius houi sp. nov. differs from all other epigean species of the genus Lagynochthonius from China except L. duo sp. nov. by the following combination of characters: the presence of a triangular epistome and the presence of two setae on tergite I and II ( Beier 1951, 1967; Hu and Zhang 2012a, b; Zhang and Zhang 2014).

Lagynochthonius houi sp. nov. differs from L. duo sp. nov. in the length of the movable chelal finger which is 0.95-1.05 × as long as the hand in males and 0.91 × as long as the hand in female, whereas in L. duo sp. nov. it is 1.11-1.27 × as long as the hand in males and 1.11 × as long as hand in female. Additionally, L. houi sp. nov. lacks intercalary tooth on the chelal fingers, whereas the fixed chelal finger posesses intercalary teeth in L. duo sp. nov.

Distribution.

China (Guizhou Province).

Figures

Figure 14. Lagynochthonius houi sp. nov. A holotype male (dorsal view) B paratype female (dorsal view).

Figure 15. Lagynochthonius houi sp. nov., holotype male (A-F) paratype female (G): A left chela (lateral view) B left chela (dorsal view) C left chelicera (dorsal view) D carapace (dorsal view) E left pedipalp (minus chela, dorsal view) F male genital area (ventral view) G female genital area (ventral view).

Figure 16. Lagynochthonius houi sp. nov., holotype male A carapace (dorsal view) B left chelicera (dorsal view), with details of teeth C rallum D coxal spines on coxae II (ventral view) E left pedipalp (minus chela, dorsal view).

Figure 17. Lagynochthonius houi sp. nov., holotype male 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). Abbreviations: for the chelal trichobothria: b = basal; sb = sub-basal; st = subterminal; t = terminal; ib = interior basal; isb = interior sub-basal; ist = interior sub-terminal; it = interior terminal; eb = exterior basal; esb = exterior sub-basal; est = exterior sub-terminal; et = exterior terminal. For other abbreviations: af, apical sensilla of fixed chelal finger, am, apical sensilla of movable chelal finger; dx, duplex trichobothria; p 1 - 2, proximal sensilla of movable chelal finger; td, modified tooth.