Adiscus transversalis Tan, 1992

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 : 73-75

Adiscus transversalis Tan, 1992

(Figs 30-1; 30-2)

Adiscus transversalis Tan, 1992b: 783 (type locality: Yunnan; type locality: IZ-CAS); Schöller et al., 2010: 608 (catalogue).

Material examined. CHINA: Holotype: male, “ Yunnan, Lushui, Yaojiaping [ Chinese letters] / 2800 m / Chinese Academy of Sciences [ Chinese letters] // 6. VI. 1981 / coll. Shuyong Wang [Chinese letters] // HOLOTYPE ”. ( IZ-CAS) ; Paratypes: 2 females, same data as holotype ; 1 female, “ Yunnan, Dali, Mt. Cang [ Cangshan ] [ Chinese letters] / 2850 m / Chinese Academy of Sciences [ Chinese letters] // 30. VI. 1981 / coll. Shuyong Wang [Chinese letters] // PARATYPE ”. ( IZ-CAS) .

Redescription (based on females as male holotype in poor condition).

Measurements. Females. BL = 2.42–2.81 mm, BW = 1.64–1.96 mm, HL = 0.89 mm, HW = 0.85 mm, PL = 0.69 mm, PW = 1.56 mm, PA = 90°, EL = 2.07 mm, EA = 160°, SL = 0.85 mm.

Body (Figs. 30-1A; 30-2A) broadly ovate; dorsum mostly yellowish brown. Head dark reddish brown; vertex slightly tinged with black; antennomeres 1–4 yellowish brown, 5–11 dark. Pronotum yellowish brown, anterior middle region and basal margin black. Elytra yellowish brown, with transverse black band extending across whole basal margin. Legs yellowish brown. Venter black, but propleura yellowish brown.

Head shiny; finely and sparsely punctate.Eyes reniform; superior eye-lobes separated by slightly greater distance than antennal insertions. Clypeus densely granulose and sparsely punctate. Anterior margin of labrum with sparse hairs. Last segment of labial palpus swollen, and apical segment of maxillary palp securiform. Antennae reaching elytral humeri, scape clubbed, pedicel oblong, about 2/3 as long as scape, antennomeres 3–5 slender, cylindrical, about as long as pedicel, 6–11 somewhat broadened, with dense hairs.

Pronotum (Figs. 30-1A; 30-2A) broad, narrowed anteriorly, basal width about 2.3 times of pronotal length. Anterior margin nearly straight. Posterior margin sinuate with fine serration, and its middle portion produced into an obtuse angle of 100°. Disc evenly convex, smooth, impunctate, anterior and hind angles about 90°.

Elytra (Figs. 30-1A; 30-2A) as broad as prothorax at base, humeri somewhat prominent. Disc distinctly and finely punctate, with 11 regular striae, intervals nearly without minute punctures. Epipleural lobe (Fig. 30-2B) weak, lateral margins slightly expanded ventrally and with weak lobe at basal 1/4 of elytron, with both lobe sides forming angle of 160°, epipleura obliquely placed and visible in lateral view.

Venter clothed with sparse pubescence. Prosternal episternum transversely and coarsely rugose, prosternal epimeron smooth, prosternum (Fig. 30-2C) broad, surface rugged, anterior and posterior margins concave, hind angles slightly protruding, lateral margin not protruding. Mesoventrite broad, twice as wide as long, hind angle slightly protruding. Pygidium with coarse punctures.

Female. Body more robust than male, apical hollow in ventrite 5 shallow. Spermatheca (Figs. 30-1C; 30- 2D) falcate, 45°-angled bending halfway, acute at apex, strongly dilated at base 1/3, then become narrower; duct weakly sclerotized, weakly and irregularly coiled. Rectal sclerites (Fig. 30-1D) strongly sclerotized, not connected between two rectangular sclerites on ventral side.

Distribution. China (Yunnan).

Diagnosis. Easily distinguished from all its congeners by the distinct broad pronotum and the elytral banding.