Trechus qunlaishanicus, Belousov & Kabak, 2020

Belousov, Igor A. & Kabak, Ilya I., 2020, New Trechus species of the kozlovi group from Sichuan (Coleoptera: Carabidae), Zootaxa 4786 (4), pp. 451-484 : 477-478

Trechus qunlaishanicus sp. n.

( Figs 21, 23–24 )

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Material: Holotype: 1(1) ♂, “ China, Sichuan, Qunlaishan Mt. R., SW of Lixian, W of Mt. “5892”, 4500–4600 m, 12.07.2000, Belousov I. & Kabak I. leg.” [31º19ʹ N / 103º00ʹ E] ( ZISP) . Paratypes: 12(6) ♂♂, 18♀♀, collected with holotype ( IZAS, MPU, ZISP, ZSM, CAG, CAK, CBK, CDW, CJS, CVZ) .

Description. Body length larger than average for the kozlovi -species group. Habitus ovate and rather depressed ( Fig. 21). Appendages of medium length, anterior legs stout, especially in males, middle and posterior legs slenderer, with rather thin tibiae. Antennae markedly surpassing base of elytra. Dark brown to blackish, with reddish mandibles; margins and suture of elytra, more rarely pronotum slightly paler, brownish. Legs yellowish, antennae markedly obscured from apical portions of segments 2–3.

Head average. Eyes medium-sized, longer than tempora, slightly protruding, tempora rather long, subconvex, with a few sparse hairs. Frontal furrows well impressed for most of their length, becoming much shallower behind level of posterior supraorbital seta, subangulate and approaching in middle; frons subconvex, smooth or with a few transverse wrinkles in median part. Supraorbital setae located in lines subparallel to body axis, posterior seta located far behind posterior margin of eye. Anterior supraorbital pores markedly foveolate, posterior one slightly foveolate.

Pronotum clearly transverse, rather flat, with maximal width in apical third, moderately constricted at base, its basal margin slightly longer than apical margin. Sides regularly and broadly arcuate, distinctly sinuate before hind angles, latter rectangular or slightly acute, with apices gently and obliquely truncate. Posterior margin straight for most of its length, shortly emarginate just near basal foveae, slightly convex near hind angles. Anterior angles broadly rounded, not or slightly salient. Lateral margins distinctly reflexed, lateral groove rather wide, broadened posteriad. Prebasal transverse impression rather deep, angulary curved in basal foveae, latter large and deep. Apical transverse impression continuous, deeper laterally. Discal foveae absent or small. Anterior marginal seta located in anterior third of pronotum, posterior seta at hind angle. Basal surface of pronotum coarsely rugose. Median line distinct, deeper near preapical transverse impression and very deep, nearly carinate near pronotal base.

Elytra large-sized; broad, ovate or oblong-ovate. Shoulders rounded. Marginal groove rather broad, approximately as wide as that of pronotum. Elytral striae distinct, though outer striae becoming much shallower and partially shortened; all striae finely punctate and distinctly waved. Stria 7 usually distinct, sinuate and directed to apical striole but usually without clear connection with it; striae 5 and 6 connected at level slightly behind umbilicate pore 6 and effaced posteriad; striae 2 and 3 connected at level between umbilicate pores 7 and 8; stria 4 variable, joining stria 3 or stria 5 at different levels. Inner intervals slightly convex, outer ones flat. Apical striole rather long, slightly curved posteriorly, nearly straight anteriorly. Anterior discal pore distinctly shifted posteriad compared to related species and located nearly in the end of the anterior quarter of elytra, posterior discal pore, on the contrary, displaced anteriad and located clearly before their mid-length, preapical pore situated far from elytral apex. Angulo-apical pore located much closer to exterior pore than to elytral suture, apical triangle markedly elongate, with inner side nearly parallel to body axis.

Microsculpture of dorsum very coarse, consisting of isodiametric meshes on head, base and apex of pronotum, slightly transverse meshes on disc of pronotum and markedly transverse meshes on elytra.

Fore tibia without distinct groove on their external surface, glabrous on anterior surface.

Aedeagus ( Figs 23–24 ), large, angularly bent near base, with rather short basal and long subcylindrical distal portions, ventral side of the latter nearly straight in lateral view. In dorsal view, the median lobe slightly sinuate, only faintly narrowed in apical portion. Apical disc large, apical lamella short and broadly rounded. Sagittal lobe well developed. Parameres rather long, each bearing 4 apical setae, left paramere clearly longer and thicker in apical portion than the right one, with a ventral apophysis. Endophallus armature with the distal piece complexly twisted.

Sexual dimorphism. Males differ in having larger body size (on average, 3.39 mm vs. 3.25 mm in females, significance level p≤0.05), smaller head (EW/HW, on average, 2.04 vs. 1.99 in females, p≤0.01), longer basal margin of pronotum (PW/PB, on average, 1.37 vs. 1.39 in females, p≤0.05; PA/PB, on average, 1.02 vs. 1.05 in females, p≤0.001) and longer elytra (EL/AL, on average, 1.23 vs. 1.20 in females, p≤0.05),

Comparative notes. This new species seems to be most closely related to T. shangensis sp. n. and T. mengensis sp. n. described above. All these species share some characters, such as the rather dark color of the upper-side, the large elytra flattened on disk, the coarse microsculpture of the dorsal surface and the large median lobe of aedeagus with long and nearly straight, tube-like distal portion and distinct apical disc ( Figs 23–24 vs. Figs 18–19 ). However, T. qunlaishanicus sp. n. differs from both these species in the darker color of body with antennae clearly obscured from segment 3 (vs. slightly obscured from segments 3–5, see Fig 21. vs. Figs 15–16), the pronotum with much broader lateral groove and coarser microsculpture of dorsum with less transverse meshes on pronotum as well as, in, on average, shallower striation of elytra (the apical connection of striae 3 and 4 usually much less impressed, often indistinct). The structure of the male genitalia is also different, with the median lobe slightly sinuate and apical portion nearly parallel-sided in dorsal view in T. qunlaishanicus sp. n. The endophallus armature differs largely in the shape of the proximal piece, which, in lateral view, is more oval vs. strip-like in the two above mentioned species.

Distribution. This species is only known from the type locality (Sichuan, Qunlaishan Mountain Range, WSW of Lixian City, W of Mount “5892”).

Bionomics. Trechus qunlaishanicus sp. n. occurs in the high alpine zone at elevations of 4500–4600 m.

Derivatio nominis. The species is named after the mountain range where it was found.

Figures

FIGURES 23–25. Male genitalia of Trechus spp. n., paratypes: a—lateral view, b—dorsal view. 23–24 —T. qunlaishanicus sp. n.; 25—T. chiguguanensis sp. n.

FIGURES 18–20. Male genitalia of Trechus spp. n., paratypes: a—lateral view, b—dorsal view. 18—T. shangensis sp. n.; 19—T. mengensis sp. n.; 20—T. cuspis sp. n.