Gastroserica (Gastroserica) muongphangensis Ahrens & Pham, 2023

Ahrens, Dirk & Pham, Phu, 2023, Updates on the taxonomy and distribution of Gastroserica Brenske, 1897, Microserica Brenske, 1894, and Moronoserica Ahrens, Lukic & Liu, 2023 (Coleoptera: Scarabaeidae: Sericinae: Sericini), Zootaxa 5346 (5), pp. 551-566 : 556-557

Gastroserica (Gastroserica) muongphangensis Ahrens & Pham , new species

Figs. 1J–M

Type material examined. Holotype ♂ “ Vietnam, Dien Bien Pro., Muong Phang Dis. Light trap, 2–10.v.2009 ” ( IEBR).

Description of holotype. Length 8.5 mm, length of elytra 5.8 mm, width 4.4 mm. Body oval, dark brown, dorsal surface dull and with robust, moderately dense, erect setae mixed with dense and very short ones.

Labroclypeus subrectangular and short, widest at base, lateral margins nearly straight in basal half, anterior angles strongly rounded; ocular canthus producing a distinct blunt angle; anterior margin strongly reflexed and nearly straight; surface strongly convex medially and moderately shiny, coarsely and irregularly sparsely punctate, with a few long, erect setae; frontoclypeal suture distinctly impressed and strongly curved; smooth area in front of eye long and 1.3 times as wide as long; ocular canthus moderately long and triangular, finely and almost glabrous, with a single terminal seta. Frons with coarse and fine, irregularly dense punctures, with a few erect setae. Eyes moderately large, ratio of diameter/interocular width: 0.5. Antenna brown, with 10 antennomeres; club with four antennomeres, first antennomere of club shorter than the three remaining antennomeres, club as long as remaining antennomeres combined. Mentum elevated and flattened anteriorly.

Pronotum large, convex, widest at base, lateral margins in basal half weakly convergent anteriorly, in anterior half strongly convex, anterior angles not produced and very strongly rounded, almost obsolete, posterior angles almost right-angled, not produced outward. Anterior margin straight, with a distinct and fine marginal line; basal margin without marginal line; surface with moderately dense and fine punctures, with minute setae in punctures, a shallow median impression absent; anterior and lateral borders setaceous. Basal margin of hypomeron strongly produced ventrally, before base distinctly transversely sulcate. Scutellum wide and long, apex sharp, with fine and dense punctures, glabrous in the middle line, minute setae present in the punctures.

Elytra oval, widest at middle, striae distinctly impressed and finely densely punctate, intervals weakly convex, with fine and sparse punctures that are almost concentrated along the striae, minutely setose in the punctures, odd intervals with single coarse punctures bearing strong erect brown setae, interior apical angle of elytra with a strong seta; epipleural edge moderately strong, ending before the convex external apical angle of elytra, epipleura densely setaceous, apical border chitinous, without short microtrichomes.

Ventral surface dull, with large and dense punctures, densely and shortly hairy, setae adpressed, metacoxa with fine adpressed setae. Mesosternum between mesocoxae wider than mesofemur, with irregularly scattered strong setae. Ratio of length of metepisternum/metacoxa 1/2.25. 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. Pygidium long, apically produced and strongly convex, with fine and dense punctures bearing fine long setae and a few robust punctures bearing robust setae, without smooth midline.

Legs moderately slender and with moderately shiny surface; femora with two longitudinal rows of setae, finely densely punctate and setose. Anterior edge of metafemur acute, lacking an adjacent serrated line; posterior margin moderately 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 1/3.75; dorsal margin sharply carinate, with two groups of spines, the basal group at nearly 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 glabrous 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 distinctly shorter than two following tarsomeres combined and little less than twice as long as dorsal tibial spur. Protibia short, bidentate, protarsal claws symmetrical.

Aedeagus: Figs. 1J–L . Habitus: Fig. 1M . Female unknown.

Diagnosis. Gastroserica (G.) muongphangensis new species in genital shape and habitus most similar to G. (G.) yingi Ahrens & Pacholátko, 2007 . It may be distinguished from the latter by the much slenderer right paramere, which is not bifurcate at the basis, and the right paramere is subequal to the left.

Etymology. The new species is named after the type locality (Muong Phang District, Dien Bien Province) (adjective in nominative case singular).

Distribution. So far known only from the type locality (Muong Phang) in Vietnam.

Figures

FIGURE 1. A–D: Gastroserica (Helioserica) kachin Ahrens & Pham, new species (holotype); E–I: G. (H.) horii Ahrens & Pham, new species (holotype). J–M: G. (Gastroserica) muongphangensis Ahrens & Pham, new species (holotype). A, E, J: Aedeagus, left side lateral view; C, H, L: Aedeagus, right side lateral view; G: Aedeagus, dorsal view; B, F, K: Parameres, dorsal view; D, I, M: Habitus (not to scale). Scale: 0.5 mm.