Gastroserica phukradung 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 : 19-20

Gastroserica phukradung Ahrens, Lukic & Liu, new species

Figs. 5E–H , 25

Type material examined. Holotype: Ô “THAI-NE, Loei prov. Phu Kradung N.P. 16°52’N 101°49’E, 16.-18.v.1999, 1000m, D. Hauck leg. / 13 Sericini Asia spec.” ( CP) . Paratypes: 4 ÔÔ, 1 ♀ “Phu Rua NP (12-1300m) Loei P., NE Thai. 27-30.IV.2006 Takakuwa, M. leg.” ( ZFMK) , 1 Ô “NE Thailand, Phu Rua, Loei Prov., Phu Rua National Park 22.V.2004 leg. S. Ohmomo ” ( ZFMK) , 7 ÔÔ “ Mt. Phu Rua Summit , Loei Prov., NE Thailand, 24.V.2004 leg. Y. Komiya ” ( ZFMK) .

Description of holotype. Length: 5.6 mm, length of elytra: 3.5 mm, width: 3.1 mm. Body oval, body including legs and antenna yellowish brown, abdomen, middle of pronotum, margins of elytra and frons blackish, antennal club little darker, dorsal surface iridescent shiny to weakly dull, nearly glabrous.

Labroclypeus semicircular, slightly wider than long, widest at base, lateral margins 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 convexly elevated, finely and coarsely, 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, otherwise with minute setae in punctures. Smooth area in front of eyes twice 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: 0.63. 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 sharp but weakly produced anterior angles, posterior angles strongly rounded. Anterior margin of pronotum straight, with robust and complete marginal line; basal marginal line absent; surface finely and moderately 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 midline narrowly 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, 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: 1/1.63. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium moderately convex and dull, with mixed finer and larger 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 moderately long and wide, widest at middle, ratio width/length:1/2.94; 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, with a few fine punctures; 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 more than twice as long as dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 5E–G . Habitus: Fig. 5H . Female unknown.

Diagnosis. Gastroserica phukradung Ahrens, Lukic & Liu, new species is in external appearance and shape of aedeagus rather similar to Gastroserica fumaria Ahrens, Lukic & Liu, new species. Gastroserica phukradung differs most of all by the shape of the left paramere which is basally more narrow (lateral view), the right one is before apex strongly bent externally, while it is almost straight in G. fumaria .

Etymology. The name of the new species is named after its occurrence in the Phu Kradun province (noun in apposition).

Figures

FIGURE 5. A–D: Gastroserica fumaria Ahrens, Lukic & Liu, new species (holotype); E–H: G. phukradung Ahrens, Lukic & Liu, new species (holotype). A, E: Aedeagus, left side lateral view; C, G: Aedeagus, right side lateral view; B, F: Parameres, dorsal view; D, H: Habitus (not to scale). Scale: 0.5 mm.

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