Pachymerium lingshouense sp. nov.

Figs 1 D, 2 D, 7

Type material examined.

Holotype. China • ♂ (CMMI 20230920007 D), Hebei Province, Lingshou, Wuyuezhai National Forest Park, 20. ix. 2023, leg. Huiqin Ma. Paratypes. China • 4 ♂♂ 5 ♀♀ (CMMI 20140921002 D, 20140927001 D – 005 D, 20230920009 D – 011 D), same locality as holotype, 20. ix. 2023, 21–27. ix. 2014, leg. Huiqin Ma.

Diagnosis.

Body length reaching at least 28 mm; number of leg-bearing segments 41–49; clypeus with two indistinct and internally areolate clypeal areas; lacking poorly defined, pigmented, weakly areolate areas close to posterior margin (Fig. 2 D); labral mid-piece with seven stout denticles, each side-piece entire, with ~ 25–27 bristles on lateral parts; coxosternite of forcipular segment with anterior denticles; chitin lines incomplete, vanishing before reaching the condyle, ~ 0.7 × as long as the coxosternite; coxopleuron with 18–23 (♂), 21–25 (♀) coxal pores in adults, opening independently on ventral and dorsal sides of coxopleuron.

Description of holotype (adult male).

Body 37 mm long; with 49 leg-bearing segments; body tapering distally. Color (in ethanol 75 %) pale orange; forcipules darker.

Cephalic capsule (Fig. 7 A, C, D) subrectangular; ~ 1.5 × longer than wide; anterior margin convex; areolation uniform on the entire surface; with an indistinct transverse suture. Clypeal areas indistinct and internally areolate; without poorly defined, pigmented, weakly areolate areas. Clypeal setae: one pair anterior, 4–5 pairs intermediate, one pair posterior. Labral mid-piece wider than long, with seven stout denticles; with ~ 25–27 bristles on lateral parts.

Antennae (Fig. 7 B) almost uniform in width; ~ 3.0 × as long as the length of the head. Basal articles only slightly more elongated (article II ~ 1.1 × as long as wide); distal articles stouter (article XIII ~ 1.0 × as long as wide); article XIV ~ 2.0 × as long as wide. Setae gradually denser and shorter from the basal articles to the distal ones. Articles I – XIII with two whorls of long, distinct setae along with numerous short setae; remaining articles equipped with uniform short setae.

Mandible (Fig. 7 E) with a single pectinate lamella with ~ 28 hyaline teeth.

First maxillae (Fig. 7 F). Coxosternite entire; uniformly areolate; with pair a of lateral lappets; 3 + 3 setae close to the anterior margin. Coxal projection subtriangular; longer than wide; ventral side with 6 + 7 setae on distal half; dorsal surface with numerous small sensilla on distal half. Telopodite with two articles, telopodite longer than coxal projection; distinctly articulated; one external lappet on each article; ventral side with 11 + 7 setae on distal half; dorsal surface with numerous small sensilla on distal half.

Second maxillae (Fig. 7 F). Coxosternite entire; uniformly areolate; anterior margin deeply concave; 6 + 8 setae on the middle part; metameric pores opening close to posterior margin. Telopodite composed of three articles; gradually narrowing towards the tip; pretarsus of telopodite pointed, almost straight and gradually tapering towards the tip.

Forcipular segment (Fig. 7 G). Tergite subtrapezoid; ~ 2.1 × as wide as long. Coxosternite ~ 1.2 × as wide as long on exposed part; anterior margin moderately projecting with respect to its condyles; anterior border with shallow medial concavity; with anterior denticles; chitin lines incomplete, vanishing before reaching the condyle, ~ 0.7 × as long as the coxosternite. Trochanteroprefemur ~ 1.9 × as long as wide. Forcipular articles from trochanteroprefemur to tarsungulum with 1, 0, 0, and 1 denticle, respectively; basal denticle of the tarsungulum is subtriangular. Tarsungulum ~ 2.5 × as long as wide. Basal denticle of tarsungulum with distal margin distinctly convex and ~ 0.3 × as long as the basal breadth of the tarsungulum. Calyx of venom gland short, ~ 1.2 × as long as wide, situated in femur.

Leg-bearing segments (Fig. 7 H, I). Tergites of leg-bearing segments with two paramedian sulci, becoming faint or obsolete on posterior segments. Metasternites subrectangular; without a mid-longitudinal sulcus. Ventral pores begin on leg-bearing segment 1 as a transverse group (~ 9 pores) close to posterior margin plus two paired pore-fields (~ 10 + 7 pores) close to anterior margin; on segment 4 the transverse group replaced by two paired pore-fields (~ 16 + 11 pores), with two paired pore-fields (~ 27 + 33 pores) close to anterior and middle regions; absent from segment 17 and posterior. Legs 1 smaller than the others; pretarsus claw-like, reaching ~ 1 / 4 of the length of the tarsus.

Ultimate leg-bearing segment (Fig. 7 J, K). Pretergite ~ 3.6 × as wide as long on exposed part. Metatergite ~ 1.1 × as wide as long, subtrapezoid. Metasternite ~ 1.1 × as wide as long; posterior margin ~ 0.4 × as wide as anterior margin; with dense setae. Coxopleuron with 19–22 pores, opening independently, scattered on the ventral and dorsal sides of coxopleuron; setae on the coxopleuron distinctly denser close to the ventral posterior edge. Ultimate leg with dense setae on ventral and lateral sides. Ultimate pretarsus claw-like; ~ 0.3 × as long as tarsus. Ultimate legs swollen, with scattered setae; dense short setae on ventral sides.

Postpedal segments (Fig. 7 J). Intermediate sternite distinct and exposed; first genital sternite separated from pleurites by distinct sutures; gonopods biarticulate, with setae; penis conical; anal pores indistinct.

Differences in paratype (adult female). Body 32–39 mm long; with 39–49 leg-bearing segments.

Ultimate leg-bearing segment (Fig. 7 L, M). Coxopleuron with 21–25 pores, opening independently, scattered on the ventral and dorsal sides of coxopleuron. Ultimate pretarsus claw-like; ~ 0.2 × as long as tarsus. Ultimate legs slender, with scattered setae; a few setae on ventral sides.

Postpedal segments (Fig. 7 L). Intermediate sternite distinct and exposed; first genital pleurosternite ~ 1.8 × as wide as long, posterior margin slightly concave, uniformly with sparse setae; gonopods lamina distinctly bilobate, with sparse setae; anal pores present.

Differences in paratype (adult male).

Body 28–35 mm long; with 45–49 leg-bearing segments.

Etymology.

The name refers to its type locality Lingshou county. We suggest the Chinese common name as “灵寿地蜈蚣”.

Remarks.

This species is also provisionally placed in the genus Pachymerium. Like Pachymerium multiseriale sp. nov., it resembles P. ferrugineum, but differs in possessing a narrow, subtriangular labrum and a clypeus with two indistinct, internally areolate clypeal areas, lacking the poorly defined, pigmented, weakly areolate areas near the posterior margin. It is distinguished from P. multiseriale by the absence of rows of dentate projections on the lateral parts of the labrum.

Distribution.

China (Hebei Province).