Adiscus glabrous Tan, 1988

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 : 35-37

Adiscus glabrous Tan, 1988

(Figs 14-1; 14-2)

Adiscus glabrous Tan, 1988: 319 (type locality: Xizang; type deposited: IZ-CAS); Schöller et al., 2010: 607 (catalogue).

Material examined. CHINA: Paratype: 1 female, “ Tibet: Motuo, Gedang [Chinese letters] /Chinese Academy of Sciences [Chinese letters] / 1900–2000 m / 26. IX. 1982 // PARATYPE ”. ( IZ-CAS); Additional material: Tibet: 1 female, Bomi, 700 m, 2–3. IX. 1983, coll. Yinheng Han ( IZ-CAS) .

Redescription. Measurements. Females. BL = 2.43–2.74 mm, BW = 1.61–1.82 mm, HL = 0.77 mm, HW = 0.75 mm, PL = 0.68 mm, PW = 1.39 mm, PA = 100°, EL = 1.96 mm, EA = 135°, SL = 0.63 mm.

Body (Figs. 14-1A; 14-2A) small and ovate; above shiny, mostly yellowish brown.Antennae pale yellow, apical 5 or 6 segments dark brown. Pronotum and elytra yellow, posterior margin, middle anterior margin of pronotum, basal posterior of elytra and lateral ridge of prosternum black; elytral disc with three small black spots, first at lateral side of humerus, second at middle along basal margin, third lateral to elytral middle region. Venter pale yellowish brown.

Head dull, finely and sparsely punctate. Eyes distinct and reniform; superior eye-lobes separated wider than antennal insertions. Antennae reaching elytral humeri, scape clubbed and broadened, pedicel oblong, shorter than scape, antennomeres 3–5 slender, shorter than pedicel, 6–11 somewhat broadened.

Pronotum (Figs. 14-1A; 14-2A) convex, smooth and shiny, much broader basely than apically, basal width about twice pronotal length. Anterior margin nearly straight. Posterior margin undulated in dorsal view, and produced into an obtuse angle of about 100° at middle. Disc evenly convex, impunctate.

Elytra (Figs. 14-1A; 14-2A) as broad as long, humeri somewhat prominent, glabrous. Disc sparsely and finely punctate, arranged in 9 regular srtriae excluding scutellar row, strial intervals without minute punctures. Epipleural lobe (Fig. 14-2B) distinct, lateral margins distinctly expanded ventrally with rounded lobe at basal 1/3 of elytron, with both lobe sides forming angle of 135°, epipleura visible in lateral view.

Venter clothed with short pubescence. Prosternum (Fig. 14-2C) trapezoidal, lateral margin prominent, broadened and bifurcate. Mesoventrite broad, about 2.5 times as wide as long. Pygidium with densely fine punctures.

Female. Apical hollow in ventrite 5 shallow and oval. Spermatheca (Figs. 14-1C; 14-2D) falcate, 50°-angled bending from apex 2/3, acute at apex, moderately sclerotized, slightly become narrower from apex 1/3; duct weakly sclerotized, irregularly coiled. Rectal sclerites (Fig. 14-1D) moderately sclerotized, slightly connected between two rectangular sclerites on ventral side.

Distribution. China (Tibet).

Diagnosis. Allied to A. exilis , distinguished chiefly by the smooth body and impunctate pronotum and elytral interstriae.