Gastroserica shaanxiana, Ahrens, Dirk & Pacholátko, Petr, 2003

Ahrens, Dirk & Pacholátko, Petr, 2003, New data on the distribution of species of Gastroserica Brenske, 1897, with descriptions of five new taxa from China and Laos (Coleoptera: Scarabaeidae: Sericini), Zootaxa 342, pp. 1-18 : 4-6

Gastroserica shaanxiana sp. n. (Figs 4­6)

Type material: Holotypus: ɗ “ China, S Shaanxi, 23.VI. road Wanyuan­Zhenba ­ 30 km S Zhenba, 32.3N 108.0E, 1000 m Jaroslav Turna leg. 2000” ( TICB). Paratypes: 1 ɗ, 3 ΨΨ ­ same data ( TICB, CA).

Description. Length: 7.1 mm, length of elytra: 4.8 mm, width: 3.9 mm. Body oval, yellowish brown, frons, antennal club, elytral margins, and two symmetrical spots on pronotal disc dark brown, dorsal surface dull, densely covered with short setae and with moderately dense, longer, erect setae interspersed.

Labroclypeus subrectangular, widest at middle, lateral margins weakly convex and slightly convergent toward base, anterior angles broadly rounded, lateral border and ocular canthus produced into a distinct obtuse angle, anterior margin strongly reflexed, straight; surface almost not convex medially and shiny, finely and coarsely but irregularly densely punctate, with numerous long, erect setae; frontoclypeal suture distinctly impressed and weakly curved; smooth area in front of eye wider than long (1.5/1); ocular canthus moderately long and slender, finely and sparsely punctate, with a short single terminal seta. Frons with coarse and fine moderately dense punctures and erect setae. Eyes moderately large, ratio of diameter/ interocular width: 0.53. Antenna yellow, 10­segmented; club dark brown with four antennomeres equal in length, club as long as the remaining antennomeres combined. Mentum elevated and flattened anteriorly.

Pronotum long, widest at base, lateral margins in posterior half subparallel, in anterior third strongly convex and convergent, before posterior angles shallowly sinuate, anterior angles not produced and strongly rounded, almost obsolete, posterior angles almost right angled, anterior margin almost straight, with a distinct and fine marginal line, basal margin without marginal line; surface with moderately dense and fine punctures, almost glabrous, with a few erect setae only and minute setae in punctures; anterior and lateral borders setaceous; basal margin of hypomeron strongly produced ventrally, before base distinctly transversely sulcate. Scutellum long, apex weakly rounded, with fine and dense punctures, medially smooth, minute setae present in the punctures.

Elytra oblong, widest at middle, striae distinctly impressed and finely densely punctate, intervals weakly convex, with fine and sparse punctures which are almost concentrated along the striae, minutely setose in the punctures, odd intervals with single coarse punctures bearing strong erect setae, interior apical angle of elytra with a strong seta; epipleural edge moderately strong, ending at the strongly convex external apical angle of elytra, epipleura densely setaceous, apical border chitinous, without short microtrichomes. Ventral surface dull, with large and dense punctures, with dense and short setae, setae adpressed, metacoxa partly glabrous, laterally with fine adpressed setae; each abdominal sternite with indistinct transversal row of coarse punctures bearing short strong setae between fine and dense punctation, all sternites with fine, short setae. Mesosternum between mesocoxae almost as wide as mesofemur, with irregularly scattered strong setae. Ratio of length of metepisternum/ metacoxa: 1/ 2.0. Pygidium long, apically produced and strongly convex, with fine and dense punctures bearing fine setae and a few robust punctures bearing robust setae, without smooth midline.

Legs moderately slender and shiny; femora finely densely punctate and setose, with two longitudinal rows of setae; anterior edge of metafemur acute, lacking an adjacent serrated line, posterior margin weakly convex, with a few fine setae medially, ventrally weakly widened in apical half but not serrate, dorsally serrate, with short setae. Metatibia moderately broad and short, at middle convexly widened, ratio width/ length: 1/ 3.0, dorsally sharply edged, with two groups of spines, the basal group at one third, apical one at two third of metatibial length, basally with a few single spines in punctures; lateral face longitudinally convex, with dense and moderately coarse punctures, some of them longitudinally impressed; ventral edge serrated, with four strong and long, equally spaced spines, medial face not punctate and smooth, apex interiorly near tarsal articulation sharply truncate. Tarsomeres dorsally glaborus and finely punctate, ventrally with sparse, short setae; metatarsomeres dorsally with strong longitudinal impressions, ventrally with a strongly serrated ridge, laterally with a strong longitudinal carina, first metatarsomere as long as the following two tarsomeres combined and less than twice as long as the upper tibial spur. Protibia short, bidentate, protarsal claws symmetrical.

Aedeagus: Figs 4–6.

FIGURES. 4–6: Gastroserica shaanxiana sp. n. (Holotype: China, S Shaanxi, road Wanyuan­ Zhenba ­ 30 km S Zhenba); 4, 6 ­ Aedeagus lateral view, 5 ­ Parameres dorsal view. Scale: 0.5 mm.

Variability. Length: 6.9–7.8 mm, length of elytra: 4.7–5.2 mm, width: 3.8–4.3 mm. In some paratypes elytra unformly reddish brown without dark lateral margins. Ψ: Antennal club with four antennomeres and almost as long as the remaining antennomeres combined, 7th antennomere subequal in length with the other antennomeres of the club; eyes equal in size to that of male, ratio of diameter/ interocular width: 0.58; pygidium apically less convex.

Diagnosis. G. shaanxiana sp. n. is very similar to G. hubeiana Ahrens in genital shape and habitus. The phallobase of both taxa are characterized by the presence of a ventral lamellous process in the apical third and by a semicircular sharply pointed apophysis at the right side of the apical phallobasis. G. shaanxiana sp. n. may be differentiated from G. hubeiana by the shape of parameres: the left paramere is simple, the right paramere is a little longer and more robust. These taxa can not be separated by the external shape.

Derivatio nominis. The new species is named for its occurrence in Shaanxi province.