Gastroserica yuebaensis Ahrens, Lukic

Ahrens, Dirk, Liu, Wangang, Lukic, Daniel & Bai, Ming, 2023, A taxonomic review of Microserica Brenske, 1894 from continental Asia (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5241 (1), pp. 1-115 : 17

Gastroserica yuebaensis Ahrens, Lukic & Liu, new species

Figs. 4I–L , 25

Type material examined. Holotype Ô [ China] “ Shaanxi, Zhouzhi, Yueba , 2012-VI-30. N: 33.585 -33.572, E: 107.765-107.788, 1139-1573m, daytime / LW1321” ( ZFMK).

Description of holotype. Length: 6.0 mm, length of elytra: 4.4 mm, width: 3.5 mm. Body oval, dark brown, legs, one longitudinal stripe at middle of the elytra and its lateral margin, margins of pronotum, labroclypeus, apex of scutellum, and antennal funiculus yellowish, antennal club brown, dorsal surface dull and nearly glabrous.

Labroclypeus transverse-elliptical, distinctly wider than long, widest at middle, lateral margins strongly convex and convergent to strongly rounded anterior angles; anterior margin widely but not shallowly emarginate medially, anterior margin strongly reflexed, lateral margin weakly reflexed; labrum strongly enlarged; lateral margins and ocular canthus produce a blunt angle; surface shiny, weakly convex, finely, densely punctate, with numerous long, erect setae; frontoclypeal suture finely incised and curved medially. Frons dull, with sparse, fine punctures, beside eyes and behind frontoclypeal suture with a few single short setae in larger punctures, otherwise with minute setae in punctures. Smooth area in front of eyes narrow, as wide as long. Ocular canthus sparsely finely punctate, narrow and moderately long (1/3 of ocular width), with a terminal seta. Eyes small, ratio of diameter/interocular width: 0.49. Antenna with ten antennomeres; club composed of four antennomeres, straight, 1.2 times as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum wide, widest at base, lateral margins evenly convex and convergent to blunt but weakly produced anterior angles, posterior angles moderately rounded. Anterior margin of pronotum straight, with fine and complete marginal line; basal marginal line absent; surface finely and densely punctate, with minute setae in punctures, anterior and lateral anterior margins sparsely setose. Hypomeron carinate, weakly produced ventrally. Scutellum triangular, finely and evenly densely punctate.

Elytra elongate, widest at middle, striae distinctly impressed, finely and densely punctate, intervals convex, with fine and sparse punctures concentrated along striae, with very minute setae in punctures, odd intervals with a few short setae; epipleural edge robust, ending at slightly rounded external apical angle of elytra, epipleura densely setose, apical border chitinous, without a fringe of short microtrichomes (visible at ca 100x magnification).

Ventral surface dull, finely and densely punctate, metasternum sparsely covered with fine, short, or very minute setae; metacoxa glabrous, with a few single setae laterally. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.7. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium strongly convex and dull, with large, dense punctures, without smooth midline, with numerous short setae at apex.

Legs moderately wide; femora finely and sparsely punctate, with two longitudinal rows of longer setae. Metafemur moderately shiny, anterior margin acute, without submarginal serrated line; anterior row of seta-bearing punctures present; ventral posterior margin finely serrate at apex, only weakly widened in apical half, dorsal posterior margin serrate, with a few short setae basally. Metatibia moderately long and wide, widest at middle, ratio width/length: 1/3.0; dorsal margin sharply carinate, with two groups of spines, basal group at middle, apical one at three quarter of metatibial length, in basal third with a few robust single setae; lateral face longitudinally convex, finely and sparsely punctate, along midline smooth, with minute setae in punctures; ventral edge finely serrate, with three robust equidistant setae; medial face smooth, apex interiorly near tarsal articulation bluntly truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally smooth; metatarsomeres glabrous, with a strongly serrated ridge ventrally and a parallel subventral smooth carina immediately beside it; first metatarsomere little shorter than following two tarsomeres combined, a quarter of its length longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 4I–K . Habitus: Fig. 4L . Female unknown.

Diagnosis. This new species is very similar to Gastroserica nitidipyga ( Nomura, 1974) . Gastroserica yuebaensis Ahrens, Lukic & Liu, new species differs from G. nitidipyga by the shorter and narrower left paramere, the narrower right paramere (lateral view).

Etymology. The name of the new species is derived from the name of the type locality, Yueba (adjective in nominative singular case).

Genbank accessions. Table 1 .

Figures

FIGURE 4. A–D: Gastroserica bisignata (Nomura, 1974) (Taiwan: Mt.Anmashan); E–H: M. nitidipyga Nomura, 1974 (China: Fujian: Mt. Liangshan-ding); I–L: G. yuebaensis Ahrens, Lukic & Liu, new species (holotype). A, E, I: Aedeagus, left side lateral view; C, G, K: Aedeagus, right side lateral view; B, F, J: Parameres, dorsal view; D, H, L: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 25. Distribution of the genus Gastroserica (Helioserica Ahrens, Lukic & Liu, new subgenus), part 2.