Lagynochthonius duo, 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 duo sp. nov.

Figs 1 , 2 , 3 , 4 , 5 Chinese name: 双毛拉伪蝎

Type material.

Holotype ♂ (Ps.-MHBU-GX2022080201): China, Guangxi, Guilin City, Longsheng Autonomous County, Longji Town, Anjiangping Area, under topsoil and in the leaf litter layer [25°42′15.15″N, 110°3′3.87″E], 419 m a.s.l., 2 August 2023, Kun Yu & Jianzhou Sun leg. Paratypes: 3 ♂ (Ps.-MHBU-GX2022080203-05) and 1 ♀ (Ps.-MHBU-GX2022080202), all with the same data as the holotype.

Etymology.

The specific name is derived from the Latin word duo, meaning dual, which refers to the presence of two setae on both tergites I and II. 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 6.17-7.27 (♂), 5.06 (♀) × as long as broad; femur 5.60-6.67 (♂), 6.70 (♀) × 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 1A , 2A-F , 3 , 4 ).

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

Cephalothorax (Figs 2D , 3A ): carapace nearly subquadrate, 0.95-0.97 × 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 triangular; four well-developed eyes; 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 10 or 11 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others (Fig. 3D ); intercoxal tubercle absent; Chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera (Figs 2C , 3B ): almost as long as carapace, 1.76-1.94 × 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 11-17 teeth, distal one largest; movable finger with 13-18 retrorse contiguous small teeth; galea completely vestigial (Fig. 3B ). Serrula exterior with 20 and serrula interior with 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. 3C ).

Pedipalp (Figs 2A, B, E , 3E , 4A, B ): trochanter 1.78-1.89, femur 5.60-6.67, patella 2.30-2.56, chela 6.17-7.27, hand 2.83-3.27 × as long as broad; femur 2.43-2.84 × as long as patella; movable chelal finger 1.11-1.27 × as long as hand and 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 at base of fixed chelal finger; esb and eb at almost the same level and ist slightly distal to esb; 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 2A , 4A ). 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 p1, p1 slightly distad of sb and very close to chelal teeth (Fig. 4A ). Microsetae (chemosensory setae) present on dorsum of chelal hand (Figs 2B , 4B ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 17 or 18 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 six or seven well-spaced, pointed teeth, plus nine or ten vestigial, rounded, 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: 5-7: 5-6: 4: T2T: 0. Sternal chaetotaxy IV-XII: 8-10: 10-12: 11-12: 10-11: 10-12: 10-12: 9: -: 2. Genital region: sternite II with 6-10 setae scattered on median area, genital opening slit-like, sternite III with 18-20 setae (Fig. 3F ).

Legs (Fig. 4C, 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 1.71-1.94 × as long as patella; tarsus 1.88-2.13 × as long as tibia. Leg IV: femoropatella 2.65-2.81 × as long as deep; tibia 4.38-5.14 × as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.50-3.20 × as long as deep (TS = 0.35-0.53), telotarsus 9.25-12.00 × as long as deep and 2.29-2.47 × as long as basitarsus (TS = 0.23-0.33). Setae of leg I (trochanter to tibia) 3-5: 7-11: 6-7: 8-12, setae of leg IV (trochanter to basitarsus) 3: 3: 7-8: 8-9: 5-8. Arolium not divided, slightly shorter than the simple claws.

Adult female (paratype) (Figs 1B , 2G ). Mostly same as males; tergal chaetotaxy I-XII: 2: 2: 4: 4: 4: 6: 6: 7: 7: 4: T2T: 0; sternal chaetotaxy IV-XII: 9: 12: 12: 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 1.24-1.44. Pedipalps: trochanter 0.16-0.17/0.09 (1.78-1.89), femur 0.56-0.60/0.09-0.10 (5.60-6.67), patella 0.21-0.24/0.09-0.10 (2.30-2.56), chela 0.74-0.80/0.11-0.12 (6.17-7.27), hand 0.34-0.37/0.11-0.12 (2.83-3.27), movable chelal finger length 0.41-0.44. Chelicera 0.29-0.33/0.16-0.17 (1.76-1.94), movable finger length 0.20-0.21. Carapace 0.34-0.36/0.35-0.38 (0.95-0.97). Leg I: trochanter 0.10-0.12/0.08 (1.25-1.50), femur 0.29-0.33/0.06 (4.83-5.50), patella 0.17/0.05-0.06 (2.83-3.40), tibia 0.15-0.17/0.04 (3.75-4.25), tarsus 0.32-0.35/0.04 (8.00-8.75). Leg IV: trochanter 0.15-0.17/0.10 (1.50-1.70), femoropatella 0.45-0.53/0.16-0.20 (2.65-2.81), tibia 0.33-0.36/0.06-0.08 (4.38-5.14), basitarsus 0.15-0.17/0.05-0.06 (2.50-3.20), telotarsus 0.36-0.39/0.03-0.04 (9.25-12.00).

Females: body length 1.57. Pedipalps: trochanter 0.17/0.11 (1.54), femur 0.67/0.10 (6.70), patella 0.26/0.11 (2.36), chela 0.91/0.18 (5.06), hand 0.44/0.18 (2.44), movable chelal finger length 0.49. Chelicera 0.37/0.21 (1.76), movable finger length 0.23. Carapace 0.38/0.43 (0.88). Leg I: trochanter 0.18/0.10 (1.80), femur 0.35/0.07 (5.00), patella 0.18/0.06 (3.00), tibia 0.18/0.06 (3.00), tarsus 0.39/0.04 (9.75). Leg IV: trochanter 0.19/0.11 (1.73), femoropatella 0.59/0.22 (2.68), tibia 0.38/0.08 (4.75), basitarsus 0.18/0.07 (2.57), telotarsus 0.42/0.04 (10.50).

Remarks.

Lagynochthonius duo sp. nov. differs from all other epigean species of the genus Lagynochthonius from China except L. medog by the tergal chaetotaxy I-IV: 2: 2: 4: 4. It differs from L. medog in the presence of an epistome, which is absent in L. medog , and in the presence of only fixed chelal fingers with intercalary teeth in L. duo sp. nov., whereas both chelal fingers have intercalary teeth in L. medog ( Beier 1951, 1967; Hu and Zhang 2012a, b; Zhang and Zhang 2014).

Distribution.

China (Guangxi).

Figures

Figure 1. Lagynochthonius duo sp. nov. A holotype male (dorsal view) B paratype female (dorsal view).

Figure 2. Lagynochthonius duo 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 3. Lagynochthonius duo 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 4. Lagynochthonius duo 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.

Figure 5. Type locality of Lagynochthonius duo sp. nov. A stone step road B selected deciduous layers C beside the stream D areas where L. duo sp. nov. specimens were collected.