Onycholabis cheni Bolkiboev & Liang sp. nov.

Fig. 1 C

Chinese common name.

陈氏爪步甲.

Type material.

Holotype. ♂ (TARI), China, Taiwan Province, Keelung City, Nuannuan District, Laoliaokeng, 25.0667°N, 121.7633°E, 290 m, 2020.05. 16, nighttime, leg. S. P. Wu, Holotype Onycholabis cheni det. Bolkiboev & Liang, 2026 [red label]. Paratypes. total 52 ♂♂ and 51 ♀♀ (IZCAS, TARI) • 7 ♂♂ and 4 ♀♀, same data as holotype, but 2020.03. 28 • 1 ♂ and 1 ♀, same data as holotype, but 2020.04. 11 • 2 ♀♀, same data as holotype, but 2020.05. 16 • 6 ♂♂ and 3 ♀♀, same data as holotype, but 2019.04. 18 • 3 ♂♂ and 6 ♀♀, same data as holotype, but 2020.01. 29 • 2 ♂♂ and 1 ♀, same data as holotype, but 2020.02. 07 • 7 ♂♂ and 3 ♀♀, same data as holotype, but 2020.02. 26 • 3 ♂♂ and 1 ♀, same data as holotype, but 2020.02. 29; 2 ♂♂ and 1 ♀, same data as holotype, but 2020.03. 07 • 4 ♂♂ and 2 ♀♀, same data as holotype, but 2021.03. 13 • 2 ♂♂ and 1 ♀, same data as holotype, but 2021.03. 29 • 1 ♀, same data as holotype, but 2021.04. 30, leg. S. P. Wu • 8 ♂♂ and 9 ♀♀, same data as holotype, but 2022.03. 22 • 1 ♂, China, same data as holotype, but 2022.04. 15 • 1 ♂ and 10 ♀♀, China, Taiwan Province, Chiayi County, Chuchi Township, Zhonghe branch of Alishan highway, 23.49075°N, 120.69969°E, 1388 m, 2017.09. 21, nighttime, leg. Liang Hongbin • 3 ♀♀, same data, but 2017.09. 22 • 1 ♂, China, Taiwan Province, Nantou County, Luku Township, Shanlinxi (Sun-link Sea Forest Recreation area), 23.6394°N, 120.7797°E, 1350 m, 2019.09. 03, leg. B. H. Kuo, S. P. Wu & Y. T. Chung • 1 ♀, same data but 23.6375°N, 120.7844°E, 1600 m, 2019.09. 09 • 2 ♂♂ and 1 ♀, China, Taiwan Province, Pingtung County, Wutai, 22.7539°N, 120.7828°E, 1000 m, 2019.10. 04, leg. B. H. Kuo, & Y. T. Chung • 2 ♂♂, China, Taiwan Province, Pingtung County, Machia, 22.6736°N, 120.6761°E, 1000 m, 2019.10. 04, leg. B. H. Kuo, & Y. T. Chung • 1 ♀, China, Taiwan Province, New Taipei City, Shihmen District, Laomei riverside, 1997.8. 21, leg. S. P. Wu. Each paratype bears a yellow label: Paratype Onycholabis cheni det. Bolkiboev & Liang, 2026.

Description.

Length: 9.4–11.3 mm.

Coloration: Body black, shiny; mandibles, labrum reddish brown; antennomeres 1–4 pale yellow, others brown; maxillary palpi pale yellow, apical palpomere reddish yellow; femora brown, tibia pale yellow, tarsi pale yellow to brown; ventral side reddish brown to black.

Microsculpture: Head hardly visible and formed of isodiametric meshes, pronotum and elytra formed of transverse meshes.

Head with small and slightly convex eyes (HW / FW = 1.58–1.82, mean 1.62, in five males and five females) and markedly constricted neck; tempora long, EYL / TL = 1.6–2.5, mean 2.20; vertex moderately convex with surface very smooth and shiny; frontal furrows deeply concave, subparallel in front and slightly divergent posteriorly, anterolateral surface of frons longitudinally smooth; anterior supraorbital seta situated anterior to mid-eye level (in several specimens with two supraorbital setae of left side, posterior supraorbital seta inserted on post-eye level); mandibles long, slender, gently curved inwards and gradually narrowing apically; terminal maxillary palpomeres slender, shorter than penultimate palpomeres, cylindrical in median portion and truncate at apices; terminal labial palpomere as long as the penultimate one; penultimate palpomeres bi-setose; median tooth of mentum bifid, with each apex sharply pointed; submentum 4 - setose; antennae filiform, extending to the middle of elytra; relative lengths of scape and antennomeres II-XI as follows: 1.10: 0.60: 2.20: 1.90: 1.40: 1.40: 1.30: 1.10: 1.10: 1.00: 1.10.

Pronotum cordate, wider than long, widest at about apical one-third, slightly narrower (in holotype) or as wide as head (in paratypes), PW / HW = 1.03–1.11 (1.07), PW / PL = 1.21–1.33 (1.26), PAW / PBW = 1.23–1.31 (1.26), PW / PAW = 1.25–1.35 (1.29), PW / PBW = 1.36–1.67 (1.42); apical margin widely and shallowly or moderately emarginate throughout; front angles rounded, obtuse at tips; lateral margins finely reflexed, arcuate before widest parts, rather gradually convergent to basal one-sixth, then slightly sinuate anterior to rectangular, moderately pointed hind angles; 1 pair of marginal setae inserted slightly before widest part, 1 pair of marginal setae situated at hind angle; basal margin distinctly bisinuate and unbordered throughout; disc moderately convex, with surface smooth, except for sparse and scattered large punctures along basal and lateral portions, median line distinctly impressed throughout, completed, basal foveae deep, rugose punctate.

Elytra subovate, moderately convex, widest slightly behind middle, almost 2 × wider than pronotum, EW / PW = 1.76–1.92 (1.87), EL / EW = 1.61–1.71 (1.67); basal border not shortened and slightly curved; shoulders less prominent than in O. hainanus and moderately rounded; lateral margins almost parallel-sided in basal portions, moderately convergent towards apices, subapical sinuation weak; apices rounded and somewhat subtruncate at sutural angle; scutellar striole long, distinctly punctate and not joining interval I; striae finely impressed, finely punctate; intervals smooth, weakly convex; interval III with first discal pore at basal one-fifth near stria III and a second behind middle and near stria II, interval IX with 16 umbilicate pores.

Prosternum rugose, punctate, proepisternum punctate in inner part, mesosternum and mesoepisterna punctate, metasternum and metepisternum smooth; metepisterna long, 2.1 × as long as wide; sternites 3–5 bi-setose; sixth visible sternite bi-setose in male, 8 - setose in female.

Legs long and slender; metacoxae bi-setose (inner seta absent); metafemora bi-setose; tarsi bisulcate; protarsomeres I – III with DAS and LAS, protarsi sulci shallow, metatarsomere I> 1.5 × as long as metatarsomere II, metatarsomere IV bilobed apically, inner lobe slightly longer than outer lobe, with LAS, without LSAS, metatarsomere V latero-ventrally asetose; claws simple (Fig. 4 G – I).

Male genitalia: Median lobe of aedeagus long and robust, slightly arcuate at basal one-third, then almost straight toward apex in lateral view, apical lamella rounded at apex in dorsal view, slightly bent ventrally; apical orifice ending at two-thirds of median lobe and not reaching basal lobe. Left paramere broadly subovate and rounded at apex; right paramere small and narrow, with rounded apex. Endophallus not covered by tiny tooth-shaped sclerite scales; in lateral view, endophallus with a weak, balloon-like, distinct fold in the middle section (Fig. 2 E, F).

Female genitalia and reproductive tract as in Fig. 3 E, F; apical gonocoxite 1.5 × shorter than basal gonocoxite, slightly curved with a relatively sharp apex, apical gonocoxite with 3 or 4 dorsolateral and 1 dorsomedial ensiform setae; basal gonocoxite with apical fringe of 8–10 setae. Bursa copulatrix small, spermatheca long, moderately arcuate, C-shaped, evenly curved throughout, with short duct, and spermathecal gland with small, spherical shape, and long duct.

Differential diagnosis.

This new species is closely similar to O. sinensis Bates, 1873, in having the pronotum cordate and with two marginal setae but differs in having the sixth visible sternite bi-setose in male (4 - setose in male of O. sinensis). It is also closely similar to O. hainanus Bolkiboev & Liang, sp. nov. in having the pronotum cordate and with two latero-marginal setae, but differs by the pronotum wider than head (PW / HW = 1.03–1.11) and moderately wider than long (PW / PL = 1.21–1.33), (pronotum narrow or as long as head (PW / HW = 0.95–1.0) and pronotum slightly wider than long (PW / PL = 1.11–1.26) in O. hainanus); elytra striae indistinctly punctate (elytra striae distinctly punctate in O. hainanus); median lobe of aedeagus robust and apical lamella slightly bent ventrally (median lobe of aedeagus slender and apical lamella strongly bent ventrally in O. hainanus).

Distribution.

China (Taiwan: Keelung City; Pingtung County; Nantou County; Chiayi County; New Taipei City) (Fig. 8 B).

Habitat.

At night, adults were collected while climbing a vertical stone surface close to a small waterfall in Chiayi County on 21 September 2017, hiding under stones in the riverbed. According to the observations of collector, Dr Shu-Ping Wu, they were abundant from January to April in a stream in Laoliaokeng (Fig. 10).

Etymology.

The new species name, cheni, is named in honor of Mr Chen Chang-Chin (陈常卿), who contributed greatly to our Carabidae research.