Adiscus ningshanensis 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 : 10-13

Adiscus ningshanensis Duan & Zhou , sp. nov.

(Figs 3-1; 3-2)

Type locality. CHINA: Shaanxi Province: Ningshan, Xunyangba .

Material examined. Holotype: male, CHINA: Shaanxi Province: Ningshan, Xunyangba , 33°55′N 108°54′E, 1368 m, by light trap, 20. VIII. 2007, coll. Hongliang Shi & Ganyan Yang ( IZ-CAS) . Paratypes: 9 females, same data as holotype ( IZ-CAS) .

Description. Measurements. Males. BL = 2.51–2.70 mm, BW = 1.68–1.78 mm, HL = 0.75 mm, HW = 0.77 mm, PL = 0.68 mm, PW = 1.54 mm, PA = 120°, EL = 2.04 mm, EA = 150°, AL = 0.71 mm, AW = 0.24 mm.

Females. BL = 2.82–2.90 mm, BW = 1.86–1.98 mm, HL = 0.81 mm, HW = 0.83 mm, PL = 0.74 mm, PW = 1.67 mm, PA = 120°, EL = 2.20 mm, EA = 150°, SL = 0.55 mm.

Body (Fig. 3-1A) small; dorsum smooth, mostly ochraceous. Antennae, labrum, and legs yellowish brown, mandibles darkish brown. Pronotum with basal margin black. Elytra with anterior margin black. Legs and venter orange ochraceous.

Head (Fig. 3-1D) round, with fine and sparse punctures and short silvery pubescence. Eyes reniform; superior eye-lobes separated by slightly greater distance than antennal insertions. Clypeus densely granulose and sparsely punctate, anterior margin slightly arched and emarginated. Antennae (Fig. 3-1E) reaching elytral humeri, scape clubbed, pedicel subspherical, about 1/2 as long as the scape, antennomeres 3–4 minute, shorter than pedicel, about equal in length, 5–11 somewhat broadened and flattened, last segment pointed apically.

Pronotum (Fig. 3-1A) convex and smooth, base much broader than apex, basal width about twice as long as pronotal length. Anterior margin nearly straight. Posterior margin sinuate with fine serration, and produced into an obtuse angle of about 120° at middle. Disc evenly convex, impunctate.

Elytra (Fig. 3-1A) with humeri prominent and glabrous, widest slightly behind humerus, feebly rounded at side and apex. Disc sparsely and finely punctate, with 11 regular striae, intervals without scattered minute punctures. Epipleural lobe (Fig. 3-2A) large, lateral margins distinctly expanded ventrally with rounded lobe at basal 1/3 of elytron, with both lobe sides forming angle of 150°; epipleura obliquely placed and indistinct in lateral view.

Venter (Fig. 3-1C) clothed with short pubescence and punctures. Prosternum (Fig. 3-2B) trapezoidal, lateral margin broad and convex strongly, lateral ridges elevated, anterior margin not protruding, posterior margin nearly straight, central ridge absent. Mesoventrite rectangular, twice as wide as long, with lateral ridges elevated. Metaventrite with sparsely fine punctures. Pygidium with dense punctures and short pubescence.

Aedeagus. (Figs. 3-1H–J; 3-2D–F) Median lobe elongate, about 3 times as long as wide, parallel-sided. Apex of median lobe slightly narrower than middle, acute at apex, moderately curved in lateral view; with several setae on each side of apex, sparsely punctate on ventral side of distal part. Median orifice with median sclerite bending inwards above surface. Inner sac rather oblong, cylindrical and convoluted, dilated at base, narrowest at apical 1/3, base slightly prominent in the middle. Tegmen Y-shaped, weakly sclerotized, almost translucent.

Female. Body more robust than male, apical hollow in ventrite 5 deep and slightly triangular. Spermatheca (Figs. 3-1F; 3-2C) falcate, 70°-angled bending halfway, weakly acute at apex, constricted at base 1/4; duct weakly sclerotized, irregularly coiled. Rectal sclerites (Fig. 3-1G) moderately sclerotized, not connected between two rectangular sclerites on ventral side.

Distribution: China (Shaanxi).

Diagnosis. This new species is similar to A. exilis , but can be distinguished by larger body size and paler body surface. Its pronotum is impunctate, its penultimate puncture-row of elytra is grooved, and its antennae are totally yellowish brown. The new species has the aedeagal venter sparsely punctate.

Etymology. The specific epithet is derived from the Chinese name (Pinyin) of the type locality, Ningshan.