Lagynochthonius gibbus, 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 gibbus sp. nov.

Figs 6 , 7 , 8 , 9 Chinese name: 驼峰拉伪蝎

Type material.

Holotype ♂ (Ps.-MHBU-GZ2022070301): China, Guizhou Province, Tongren City, Jiangkou County, 500 m near Wanjiatun, under topsoil and in the leaf litter layer [27°43′32.5″N, 108°41′17.9″E], 509 m a.s.l., 3 July 2022, Yanmeng Hou, Lu Zhang, Nana Zhan, Jianzhou Sun & Long Lin leg. Paratype: 1 ♀ (Ps.-MHBU-GZ2022070302), all with the same data as the holotype, 2 ♂ (Ps.-MHBU-GZ2022062805-06) and 2 ♀ (Ps.-MHBU-GZ2022062803-04): Tongren City, Sinan County, Zhangjiazhai Town, 700 m near Zhangjiaping, under topsoil and in the leaf litter layer [27°56′39.16″N, 108°4′21.8″E], 731 m a.s.l., 28 June 20, Yanmeng Hou, Lu Zhang, Nana Zhan, Jianzhou Sun & Long Lin leg.

Etymology.

The specific name is derived from the Latin word gibbus, meaning hump-shaped, which refers to the shape of epistome. A noun in apposition.

Diagnosis.

(♂♀). Moderately sized epigean species; carapace with four eyes, anterior margin smooth and epistome hump-shaped; tergites I-IV each with four setae. Rallum with eight blades. Pedipalps slender, chela 6.64-7.00 (♂), 5.12-5.69 (♀) × as long as broad; femur 5.78-7.00 (♂), 5.64-6.33 (♀) × as long as broad; only fixed chelal finger with intercalary teeth and 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 6A , 7A-F , 8 , 9 ).

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

Cephalothorax (Figs 7D , 8A ): carapace nearly subquadrate, 0.97-1.03 × as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrate; epistome small and hump-shaped; 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. 8D ); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 7C , 8B ): almost as long as carapace, 1.71-2.00 × 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 palm has moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 12-15 teeth, distal one largest; movable finger with 16-18 retrorse contiguous small teeth; galea completely vestigial (Fig. 8B ). Serrula exterior with 17-20 and serrula interior with 14-20 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. 8C ).

Pedipalp (Figs 7A, B, E , 8E , 9A, B ): trochanter 1.78-1.89, femur 5.78-7.00, patella 2.33-2.56, chela 6.64-7.00, hand 3.09-3.18 × as long as broad; femur 2.43-2.60 × as long as patella; movable chelal finger 1.15-1.20 × as long as hand and 0.53-0.55 × 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, 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 and close to it (Figs 7A , 9A ). 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 proximad of sb and very close to chelal teeth (Fig. 9A ). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 7B , 9B ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 20 or 21 well-spaced, pointed teeth, plus three or four intercalary microdenticles, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with 6-8 well-spaced, pointed teeth, plus 5-7 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: 4: 4: 4: 4: 4: 4: 5-6: 6-7: 6: 4: T2T: 0. Sternal chaetotaxy IV-XII: 10-12: 12-16: 10-13: 12-13: 12-13: 11-12: 9-10: -: 2. Genital region: sternite II with eight setae scattered on median area, genital opening slit-like, sternite III with 18-24 setae (Fig. 7F ).

Legs (Fig. 9C, D ): fine granulation present on anterodorsal faces of trochanter IV, femur I; scale-like texture display on anterodorsal faces of femoropatella IV. Leg I: femur 1.65-1.71 × as long as patella; tarsus 2.06-2.20 × as long as tibia. Leg IV: femoropatella 2.50-3.06 × as long as deep; tibia 4.43-4.71 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.33-3.40 × as long as deep (TS = 0.29-0.42), telotarsus 9.00-12.00 × as long as deep and 2.12-2.57 × as long as basitarsus (TS = 0.25-0.28). Setae of leg I (trochanter to tibia) 3-4: 7-11: 6-8: 8-9, setae of leg IV (trochanter to basitarsus) 3: 2-3: 4-7: 7-9: 6-10. Arolium not divided, slightly shorter than the simple claws.

Adult females (paratypes) (Figs 6B , 7G ). Mostly same as males; tergal chaetotaxy I-XII: 4: 4: 4: 4-5: 5-6: 6: 5-6: 6: 5-8: 4-5: T2T: 0; sternal chaetotaxy IV-XII: 10-13: 11-13: 11-13: 10-14: 10-13: 10-13: 9-10: -: 2. Genital region: sternite II with 10 setae scattered on median area, sternite III with a row of 10-12 setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.23-1.39. Pedipalps: trochanter 0.16-0.17/0.09 (1.78-1.89), femur 0.52-0.56/0.08-0.09 (5.78-7.00), patella 0.20-0.23/0.08-0.09 (2.33-2.56), chela 0.73-0.77/0.11 (6.64-7.00), hand 0.34-0.35/0.11 (3.09-3.18), movable chelal finger length 0.39-0.42. Chelicera 0.29-0.30/0.15-0.17 (1.71-2.00), movable finger length 0.18-0.19. Carapace 0.33-0.35/0.34-0.35 (0.97-1.03). Leg I: trochanter 0.10-0.11/0.08-0.09 (1.11-1.38), femur 0.28-0.30/0.06 (4.67-5.00), patella 0.17-0.18/0.05 (3.40-3.60), tibia 0.15-0.16/0.04 (3.75-4.00), tarsus 0.33/0.03-0.04 (8.25-11.00). Leg IV: trochanter 0.10-0.17/0.10-0.11 (1.00-1.70), femoropatella 0.48-0.50/0.16-0.20 (2.50-3.06), tibia 0.31-0.33/0.07 (4.43-4.71), basitarsus 0.14-0.17/0.03-0.04 (2.33-3.40), telotarsus 0.36/0.03-0.04 (9.00-12.00).

Females: body length 1.64-1.82. Pedipalps: trochanter 0.16-0.19/0.09-0.11 (1.60-1.78), femur 0.57-0.64/0.09-0.11 (5.64-6.33), patella 0.23-0.26/0.08-0.12 (1.92-2.30), chela 0.79-0.91/0.15-0.17 (5.12-5.69), hand 0.38-0.43/0.15-0.17 (2.53-2.69), movable chelal finger length 0.42-0.48. Chelicera 0.34-0.38/0.19-0.22 (1.72-1.79), movable finger length 0.21-0.24. Carapace 0.35-0.40/0.39-0.44 (0.88-0.91). Leg I: trochanter 0.12-0.13/0.07-0.09 (1.33-1.71), femur 0.29-0.33/0.06-0.07 (4.71-5.50), patella 0.16-0.19/0.04-0.06 (2.67-4.75), tibia 0.15-0.18/0.04-0.05 (3.60-3.75), tarsus 0.34-0.37/0.04 (8.50-9.25). Leg IV: trochanter 0.16-0.17/0.10-0.14 (1.14-1.70), femoropatella 0.49-0.56/0.18-0.22 (2.52-2.72), tibia 0.33-0.37/0.06-0.08 (4.50-4.71), basitarsus 0.17-0.19/0.06 (2.83-3.17), telotarsus 0.36-0.43/0.03-0.04 (10.00-12.00).

Remarks.

Lagynochthonius gibbus sp. nov. most closely resembles L. duo sp. nov. due to the presence of intercalary teeth only on the fixed chelal finger, the presence of eight blades on rallum, and similar size (chela length of males 0.73-0.80 mm, females 0.79-0.91 mm). However, the new species differs from L. duo sp. nov. in the shape of the epistome which is hump-shaped in L. gibbus sp. nov., but triangular in L. duo sp. nov., and in the number of setae on tergites I and II, with four setae on each in L. gibbus sp. nov. compared to two setae on each in L. duo sp. nov.

Distribution.

China (Guizhou Province).

Figures

Figure 6. Lagynochthonius gibbus sp. nov. A holotype male (dorsal view) B paratype female (dorsal view).

Figure 7. Lagynochthonius gibbus sp. nov., holotype male (A-F) paratype female (G): A left chela (lateral view) B left chela (dorsal view) C right 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 8. Lagynochthonius gibbus sp. nov., holotype male A carapace (dorsal view) B right 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 9. Lagynochthonius gibbus 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.