Gastroserica cognata ( Frey, 1972 ) Ahrens & Liu & Lukic & Bai, 2023

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 : 28-29

Gastroserica cognata ( Frey, 1972) new combination

Figs. 8A–E , 24

Microserica cognata Frey, 1972: 204 .

Type material examined. Holotype: Ô “ Viet Nam Dalat 6 km S 1400-1500m 9.VI.-7.VII.1964 ” ( BPBM).

Additional material examined. 1 Ô, 1 ♀ “C-Vietnam, Tira Tien Hue Prov. , Phu Loc Bach Ma NP, Top area 05.- 09.V.2019, 1250-1400m, 16°11’39’’N 107°51’12’’E, LF, leg. M. Hartmann / 1132 Sericini Asia spec.” ( NME) .

Redescription. Length: 5.9 mm, length of elytra: 4.5 mm, width: 3.6 mm. Body oval, body including legs and antenna yellow, multiple symmetric, small dots on pronotum and elytra, abdomen including pygidium dark brown, frons posteriorly slightly darker; dorsal surface dull, nearly glabrous.

Labroclypeus subrectangular, distinctly wider than long, widest at base, lateral margins basally slightly narrowed, convex and convergent to strongly rounded anterior angles; anterior margin weakly incised medially, margins weakly reflexed; lateral margins and ocular canthus produce a blunt angle; surface weakly shiny, medially weakly convexly elevated, coarsely, densely punctate, with numerous long, erect setae; frontoclypeal suture finely incised and curved medially. Frons dull, with dense, fine punctures, with a few long setae beside eyes, otherwise with minute setae in punctures. Smooth area in front of eyes narrow, only as wide as long. Ocular canthus wide, short (1/3 of ocular width), sparsely finely punctate, without terminal seta. Eyes small, ratio of diameter/interocular width: 0.53. Antenna with ten antennomeres; club composed of four antennomeres, straight, 1.1 times as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum wide, widest at middle, lateral margins evenly convex and convergent to rectangular and moderately produced anterior angles and to well-rounded posterior angles. Anterior margin of pronotum straight, with fine, 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, evenly finely and densely punctate, impunctate along midline.

Elytra short, widest at middle, striae finely impressed, finely and densely punctate and darker, intervals weakly convex, with fine and very sparse punctures concentrated along striae, with minute setae in punctures, elytra with a single band of transversal and symmetrical dark dots, of which the ones of the odd intervals are positioned half of their length before the ones of the even intervals, 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 shiny, 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 shiny, with dense, fine punctures, without smooth midline, almost glabrous, with a few short setae at apex, otherwise with minute setae in punctures.

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 distinctly serrate in apical entire half and widened, dorsal posterior margin serrate, with a few short setae basally. Metatibia moderately long and wide, widest at middle, ratio width/length:1/3.2; dorsal margin sharply carinate, with two groups of spines, basal group at middle, apical one at three quarters of metatibial length, in basal third with a few robust single setae in punctures with serrated margin; lateral face longitudinally convex, finely and sparsely punctate, with minute setae in punctures; ventral edge finely serrate, with three robust equidistant setae; medial face smooth, apex interiorly near tarsal articulation sharply truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally impunctate; metatarsomeres glabrous, with a strongly serrated ridge ventrally and a parallel subventral smooth carina immediately beside it; first metatarsomere as long as following two tarsomeres combined and twice as long as dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 8A–D . Habitus: Fig. 8E .

Variation. Female: Color less dark, dots on elytra less clear, frons yellow; antennal club of female short, as long as remining antennomeres combined, composed of three lamellae.

Figures

FIGURE 8. A–E: Gastroserica cognata (Frey, 1972) (Vietnam: Phu Loc Bach Ma NP); F–I: G. bannok Ahrens, Lukic & Liu, new species (holotype). A, F: Aedeagus, left side lateral view; D, H: Aedeagus, right side lateral view; B, C, G: Parameres, dorsal view; E, I: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 24. Distribution of the genus Gastroserica (Helioserica Ahrens, Lukic & Liu, new subgenus), part 1.