Microserica helferi Bohacz & Ahrens, 2020

Bohacz, Claudia & Ahrens, Dirk, 2020, New species of the Microserica lineata group from Laos and Thailand (Coleoptera Scarabaeidae: Melolonthinae: Sericini), Zootaxa 4859 (2), pp. 263-274 : 270-271

Microserica helferi Bohacz & Ahrens , new species

( Figs. 3 E–H)

Type material examined. Holotype, ♂: “Ind. or. Helfer/ Tenasserim/ 1066 Sericini Asia spec.” ( NMPC) . Paratypes: 3 ♂♂ “Mus. Pragense Tenasserim Coll. Helfer ” (2 ♂♂ NMPC, 1 ♂ ZFMK) .

Description of the holotype. Length: 5.4 mm, length of elytra: 4.2 mm, width: 3.8 mm. Body oval, yellowish brown; frons, small spots elytral intervals, and two smaller spots on each side of pronotum darker brown with greenish shine, dorsal surface dull, labroclypeus simply shiny; dorsal surface almost evenly and moderately densely covered with small white setae, dark spots glabrous.

Labroclypeus subtrapezoidal and short, widest at base, lateral margins convex and convergent anteriorly, anterior angles broadly rounded, lateral border and ocular canthus produced into an indistinct obtuse angle, anterior and lateral margins moderately reflexed, anterior margin weakly sinuate medially; surface weakly convex medially and shiny, finely and densely punctate, with a few long, erect setae anteriorly; frontoclypeal suture indistinctly impressed and weakly curved; smooth area in front of eye twice as wide as long; ocular canthus short and triangular, almost sparsely finely punctate, with a short single terminal seta. Frons dull, glabrous with fine and moderately dense punctures, beside eyes with a few long erect setae. Eyes moderately large, ratio of diameter/ interocular width: 0.68. Antenna yellow, with ten antennomeres; club with four antennomeres subequal in length, club slightly longer than remaining antennomeres combined. Mentum weakly convexly elevated anteriorly.

Pronotum wide, widest at base, lateral margins moderately curved and convergent anteriorly, anterior angles moderately produced and acute, posterior angles moderately blunt; anterior margin convexly produced medially, with a distinct and fine marginal line, basal margin without marginal line; surface with dense and fine punctures, with adpressed white minute setae in punctures, darker sport with less dense punctures; anterior and lateral borders sparsely setose; hypomeron carinate, its basal margin not produced ventrally. Scutellum narrow and short, apex weakly rounded, with fine and moderately dense punctures, with minute setae in punctures.

Elytra short oval, widest at posterior third, striae finely impressed and finely densely punctate, intervals moderately convex and finely punctate, punctures concentrated long striae, throughout with fine white setae in punctures; interior apical angle of elytron with a robust seta; margins, odd intervals, and a glabrous spot before apex dark, before apex with a dark glabrous spot; epipleural edge robust but convex, ending at strongly convex external apical angle of elytra; epipleura densely setose, apical border broadly membraneous.

Ventral surface dull, with fine and dense punctures, with dense short setae, setae adpressed; metacoxa minutely setose, laterally with robust adpressed setae; each abdominal sternite with indistinct transversal row of coarse and dense punctures, sternite bearing short strong setae between fine and dense punctation, all sternites bearing minute white setae. Mesosternum between mesocoxae almost as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/ 1.72. Pygidium yellow, weakly convex, with fine and moderately dense punctures bearing fine white setae, larger setae abraded, without smooth midline.

Legs moderately slender; femora on ventral surface dull, finely and moderately densely punctate, glabrous, with two longitudinal rows of setae; anterior edge of metafemur acute, with a robust adjacent continuously serrated line, posterior margin weakly convex and glabrous, ventrally weakly widened in apical half but not serrate, posterior margin dorsally not serrate. Metatibia moderately slender and long, widest at middle, ratio width/ length: 1/ 3.0, dorsally longitudinally convex, with two groups of spines, the basal group shortly before middle, apical one at three quarters of metatibial length, basally with a few single spines in the punctures; lateral face longitudinally convex, with dense and moderately coarse punctures, along the middle of lateral face narrowly impunctate, punctures with minute setae, with a straight serrated line from base to posterior group of spines which is interrupted by anterior group of spines; ventral margin sharp and serrated, with five strong and long, equidistant spines; medial face impunctate and smooth, apex interiorly (near tarsal articulation) distinctly truncate. Tarsomeres dorsally glabrous and impunctate, ventrally with a very few sparse, short setae; metatarsomeres ventrally with a single strongly serrated carina, a subventral carina lacking, first metatarsomere as long as following two tarsomeres combined and twice as long as dorsal metatibial spur. Protibia short, bidentate, protarsal claws symmetrical.

Aedeagus: Figs. 3 E–G.

Female unknown.

Diagnosis. Microserica helferi new species differs from all other species of the Microserica lineata group by the narrow and short, strongly curved right paramere.

Etymology. The name of the new species (noun in genitive case) is derived from the name of its collector, Jan Vilém Helfer.

Variation. Length: 5.4–5.6 mm, length of elytra: 4.1–4.2 mm, width: 3.4–3.8 mm.

Figures

FIGURES 3A–L. A–D, Microserica banvaneue Bohacz & Ahrens, new species (holotype); E–H, M. helferi Bohacz & Ahrens, new species (holotype); I–L, M. tenasserimensis Bohacz & Ahrens, 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.