Gastroserica bannok 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 : 29-30

Gastroserica bannok Ahrens, Lukic & Liu, new species

Figs. 8F–I , 24

Type material examined. Holotype: Ô “ LAOS centr., Bolikhamsai prov., Ban Nok env., 9.- 14.5.1998 Route No. 8, alt. 220+ 50m, N 18°08.7, E 104°28.1 ( GPS), E. Jendek & O. Šauša leg. / 37 Sericini Asia spec.” ( CP) . Paratypes: 1 Ô “ LAOS, Sekong prov. ca. 12km S Sekong, Tad Faek waterfalls (at light) 15°14.7’N, 106°45.1’E, 118 m Jiři Hájek leg. 8.+ 12.v.2010 / 1128 Sericini Asia spec.” ( NMPC) .

Description of holotype. Length: 5.0 mm, length of elytra: 3.1 mm, width: 2.8 mm. Body oval, yellow, antennal club brown, margins of elytra and frons blackish, dorsal surface shiny, nearly glabrous.

Labroclypeus narrow and almost square, as wide as long, widest at base, lateral margins moderately 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 medially weakly convexly elevated, finely and coarsely, densely punctate, with a few long, erect setae; frontoclypeal suture finely incised and curved medially. Frons shiny, with sparse, fine punctures, beside eyes with a few single long setae, otherwise glabrous. 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 moderately large, ratio of diameter/interocular width: 0.77. Antenna with ten antennomeres; club composed of four antennomeres, weakly reflexed, 1.8 times as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum wide, widest at posterior third, lateral margins evenly convex and convergent to rectangular and moderately produced anterior angles, posterior angles blunt and moderately rounded. Anterior margin of pronotum 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, coarsely and densely punctate, on midline impunctate.

Elytra short, widest at middle, striae finely impressed, finely and densely punctate, intervals weakly 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 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: 1/1.73. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium strongly convex and shiny, with mixed sparse, finer and dense, larger, partly longitudinally rugose punctures, without smooth midline, with numerous short setae and a few longer in the larger 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 finely serrate at apex, only weakly widened in apical half, dorsal posterior margin serrate, with a few short setae basally. Metatibia short and wide, widest at middle, ratio width/length:1/2.9; dorsal margin sharply carinate, with two groups of spines, basal group shortly before middle, apical one at two thirds 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 impunctate; 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 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. 8F–H . Habitus: Fig. 8I . Female unknown.

Diagnosis. Gastroserica bannok Ahrens, Lukic & Liu, new species is in external appearance G. lucidomarginalis Ahrens, Lukic & Liu, new species, while in shape of aedeagus it is more similar to G. cognata ( Frey, 1972) . From the latter G. bannok Ahrens, Lukic & Liu, new species differs by the lacking dots on the elytra and the shape of parameres: the phallobase is more strongly curved (lateral view) in G. cognata , the left paramere has the basal lobe more developed mesally rather basally, as in G. cognata . From G. lucidomarginalis Ahrens, Lukic & Liu, new species G. bannok Ahrens, Lukic & Liu, new species differs by the basal lobe of the left paramere being not developed distally but only mesally.

Etymology. The name of the new species is derived from the type locality, Ban Nok (noun in apposition).

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.