Adiscus tanae Duan & Zhou, 2022

Duan, Wen-Yuan & Zhou, Hong-Zhang, 2022, Revision of the genus Adiscus Gistel, 1857 (Coleoptera: Chrysomelidae, Cryptocephalinae) from mainland China, Zootaxa 5096 (1), pp. 1-80 : 13-15

Adiscus tanae Duan & Zhou , sp. nov.

(Figs 4-1; 4-2; 4-3)

Type locality. CHINA: Tibet: Cona County .

Material examined. Holotype: male, CHINA: Tibet: Cona County, Lemenba Nationality Township, Senmuzha Scenic Area , 27°83′N 91°73′E, 2791 m, 19. VIII. 2019, coll. Renjie Zhang ( IZ-CAS).

Description. Measurements. Male. BL = 2.34 mm, BW = 1.77 mm, HL = 0.65 mm, HW = 0.70 mm, PL = 0.73 mm, PW = 1.58 mm, EL = 1.75 mm, AL = 0.95 mm, AW = 0.35 mm.

Body (Fig. 4-1A) short ovate, subquadrate with rounded angles; dorsum smooth. Head pale testaceous, apical part fuscous. Antennomeres 1–5 yellowish brown, 6–11 fuscous; clypeus yellowish brown; labrum and mandibles slightly reddish brown, and apex of mandibles black. Pronotum yellowish brown, basal margin narrowly black. Elytra darkish brown, with two yellowish brown markings, one on disc, a short stripe, extending from suture to 3 rd puncture row; the other at apex, oval. Venter with middle darkish brown, apex yellowish brown.

Head (Fig. 4-1D) dull; finely and sparsely punctate; partly strigose on frons. Eyes reniform, distinctly and deeply emarginated; superior eye-lobes separated by moderately greater distance than antennal insertions. Clypeus slightly prominent and declivous, finely wrinkled, with fine pubescence, anterior margin arched and emarginated apically. Antennae (Fig. 4-1C) long and thick, densely pubescent, reaching elytral humeri; scape clubbed, pedicel subspherical, slightly long, about 2/3 as long as scape, antennomeres 3–5 short and thin, each about equal in length and shorter than pedicel, 6–11 somewhat broadened and flattened, narrow at base and broad apically, last segment pointed apically.

Pronotum (Fig. 4-1A) convex and smooth, much broader basely than apically, with basal width about twice of pronotal length. Anterior margin nearly straight. Posterior margin undulated and produced into an acute angle of about 80° at middle. Disc evenly convex, impunctate.

Elytra (Fig. 4-1A) with humeri prominent and glabrous, as broad as prothorax at base, widest slightly behind humeri, feebly rounded at side and apex. Disc sparsely and distinctly punctate, with 11 regular striae, intervals without minute punctures. Epipleural lobe (Fig. 4-3A) large, lateral margins distinctly expanded ventrally with rounded lobe at basal 1/3 of elytron, with both lobe sides forming angle of 130°; epipleura obliquely placed and visible in lateral view.

Venter (Fig. 4-1E) clothed with silver pubescence and distinct punctures. Prosternum (Fig. 4-3B) trapezoidal, lateral margin broad and convex strongly, lateral ridges elevated, anterior and posterior margins slightly concave, central ridge absent. Mesoventrite rectangular, 1.5 times as wide as long, lateral ridges slightly elevated. Metaventrite with distinct coarse punctures. Pygidium with dense punctures and pubescence.

Aedeagus. (Figs. 4-2; 4-3C–E) Median lobe elongate, about 2.8 times as long as wide, apical 1/3 of median lobe nearly parallel-sided, middle part constricted. Apex of median lobe slightly narrower than middle, a little acute at apex, moderately curved in lateral view, without setae on each side of apex, densely punctate on ventral side of distal part. Median orifice with median sclerite bending inwards beyond surface. Inner sac rather oblong cylindrical and oblong, middle part spherical. Tegmen Y-shaped, weakly sclerotized, almost translucent.

Distribution: China (Tibet).

Diagnosis. This species is easily distinguished from all its congeners by the elytra with two yellowish brown markings and the aedeagus without pubescence. The female is unknown.

Etymology. The specific epithet is named in memory of the former professor, Ms. Tan Juan-jie.