Adiscus tibialis Chen & Pu, 1980

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 : 71-73

Adiscus tibialis Chen & Pu, 1980

(Figs 29-1; 29-2)

Adiscus tibialis Chen & Pu, 1980: 111 (type locality: Yunnan; type deposited: IZ-CAS); Schöller et al., 2010: 608 (catalogue).

Material examined. CHINA: Holotype: male, “ Yunnan: Xishuangbanna Mengzhe [Chinese letters] / Chinese Academy of Sciences [ Chinese letters] // 29. VI. 1958 / coll. Shuyong Wang [Chinese letters] // HOLOTYPE ”. ( IZ-CAS) ; Paratypes: 1 male, “ Yunnan: Xishuangbanna Mengzhe [Chinese letters] / Chinese Academy of Sciences [ Chinese letters] // 25. VI. 1958 / coll. Shuyong Wang [Chinese letters] // PARATYPE ”. ( IZ-CAS) ; 1 male, “ Yunnan: Xishuangbanna Mengzhe [Chinese letters] / Chinese Academy of Sciences [ Chinese letters] // 26. VI. 1958 / coll. Shuyong Wang [Chinese letters] // PARATYPE ”. ( IZ-CAS) ; 1 female, same data as holotype .

Redescription. Measurements. Males. BL = 2.14–2.53 mm, BW = 1.75–1.98 mm, HL = 0.83 mm, HW = 0.75 mm, PL = 0.68 mm, PW = 1.62 mm, PA = 110°, EL = 1.83 mm, EA = 150°, AL = 1.04 mm, AW = 0.37 mm.

Female. BL = 2.55 mm, BW = 2.08 mm, HL = 0.89 mm, HW = 0.81 mm, PL = 0.74 mm, PW = 1.76 mm, PA = 110°, EL = 1.97 mm, EA = 150°, SL = 0.42 mm.

Body (Figs. 29-1A; 29-2A) nearly round, dorsum convex, mostly ochraceous. Head dark ochraceous; vertex black, antennomeres 1–5 yellowish brown, 6–11 darkish brown. Pronotum ochraceous, basal margin black; two black transverse subquadrate patches along anterior margin. Elytra ochraceous, basal margin and suture black, seven black marks on each elytron in three rows, outer row with two elongate marks along lateral margin, second row with three round or oval spots on middle of disc, third row with two round spots on suture; sometimes four marks on each elytron (Fig. 29-A). Apex of legs and the surface of tibiae black, sometimes metaventrite black.

Head dull, with fine and coarse punctures, vertex with denser and coarser punctures than frons. Eyes reniform; deeply emarginated below middle; superior eye-lobes separated by same distance as antennal insertions. Antennae reaching elytral humeri, scape clubbed, pedicel oblong, about half as long as scape, antennomeres 3–5 slender, 6–11 somewhat broadened and flattened, last segment pointed apically.

Pronotum (Figs. 29-1A; 29-2A) convex, much broader basely than apically, basal width about 2.4 times pronotal length.Anterior margin slightly curved. Posterior margin undulated and produced into an obtuse angle of about 110° at middle. Disc evenly convex, with dense fine and coarse punctures.

Elytra (Figs. 29-1A; 29-2A) as broad as prothorax at base, humeri somewhat prominent, glabrous. Disc punctate, with 11 regular striae, intervals with scattered minute punctures, puncture striae irregular on apical slope. Epipleural lobe (Fig. 29-2B) large, lateral margins slightly expanded ventrally and with rounded lobe at basal 1/4 of elytron, with both lobe sides forming angle of 150°, epipleura invisible in lateral view.

Venter clothed with pubescence and fine punctures. Prosternum (Fig. 29-2C) broad, subquadrate; lateral ridges elevated, and bifurcate, arcuate in lateral view. Pygidium with dense punctures and slightly long pubescence.

Aedeagus. (Figs. 29-1D–F; 29-2D–F) Median lobe elongate, about 3 times as long as wide. Apex of median lobe slightly narrower than middle, acute at apex, papillate, moderately curved in lateral view; with several setae on each side of apex, indistinctly and densely punctate on ventral side of distal part. Median orifice with median sclerite bending inwards beyond surface. Inner sac rather narrow, about 1.5 times as long as wide, cylindrical, dilated at base slightly round, but narrowed at apex. Tegmen Y-shaped, weakly sclerotized, almost translucent.

Female. Body more robust than male, apical hollow in ventrite 5 shallow and triangular. Spermatheca (Figs. 29-1C; 29-2G) s-shaped, 70°-angled bending 1/5 from base, and then bending to negative direction at base 2/5, acute at apex; duct weakly sclerotized, irregularly coiling 2–3 times. Rectal sclerites (Fig. 29-1G) moderately sclerotized, sclerites slightly narrow, not connected between two rectangular sclerites on ventral side.

Distribution. China (Fujian, Yunnan).

Diagnosis. This species is similar to A. humeralis , but the elytral bands are distinctly different; and A. tibialis has pronotum with black bands and epipleura invisible in lateral view.