Gastroserica quateorum ( 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 : 30-31

Gastroserica quateorum ( Frey, 1972) new combination

Figs. 9A–D , 25

Microserica quateorum Frey, 1972: 204 .

Type material examined. Paratype: 1 Ô “ Viet Nam 20 km Di Linh (Djiring) 22-28.IV.60 / L.W. Quate collector / Paratype Microserica quateorum G. Frey 1972 ” ( CF) .

Redescription (of paratype). Length: 5.2 mm, length of elytra: 3.8 mm, width: 3.8 mm. Body oval, body brown, head, legs, antenna, metacoxa, anterior parts of elytra, and margins and a median line of pronotum yellowish, dorsal surface iridescent shiny, partly dull; nearly glabrous.

Labroclypeus subrectangular, slightly wider than long, widest at base, lateral margins in basal half subparallel and straight, anteriorly strongly convex and convergent to strongly rounded anterior angles; anterior margin weakly emarginate medially, margins weakly reflexed; lateral margins and ocular canthus produce a blunt angle; surface shiny, medially weakly convex, finely and coarsely, densely punctate, with numerous long, erect setae; frontoclypeal suture finely incised and curved medially. Frons dull-iridescent, with sparse, fine punctures, beside eyes and behind lateral frontoclypeal suture with a few single short setae, otherwise with minute setae in punctures. Smooth area in front of eyes 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: 0.53. Antenna with ten antennomeres; club composed of four antennomeres, slightly reflexed at apex, 1.5 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 sharp and distinctly produced anterior angles, posterior angles strongly rounded. Anterior margin of pronotum weakly convex, 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 densely punctate, on median base impunctate.

Elytra short, 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, penultimate lateral interval 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: 1/1.86. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium weakly convex and dull, with mixed finer and larger punctures, without smooth midline, with numerous fine adpressed along the apical margin and a few longer erect 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 serrate in apical half, weakly widened; dorsal posterior margin serrate, with a few short setae basally. Metatibia moderately long and wide, widest at middle, ratio width/length: 1/2.7; 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 sharply 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, almost twice as long as dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 9A–C . Habitus: Fig. 9D .

Figures

FIGURE 9. A–D: Gastroserica quateorum (Frey, 1972) (Paratype: Viet Nam 20 km Di Linh). A: Aedeagus, left side lateral view; C: Aedeagus, right side lateral view; B: Parameres, dorsal view; D: Habitus (not to scale). Scale: 0.5 mm.

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