Microserica ventrosa 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 : 265-267

Microserica ventrosa Bohacz & Ahrens , new species

( Figs. 2 A–D)

Type material examined. Holotype, ♂: “ Laos, 21°09’N 101°19’E Louang Namtha -> Muang Sing 5-31.v.1997 900m Vit Kuban leg., 1200m / 46 Sericini Asia spec.” (CP) . Paratypes: 2 ♂♂ “ Laos centr., 13. -24. V .1997 15 km NW Louang Namtha N21°07.5, E 101°21.0, alt. 750m + 100m E. Jendek & O. Šauša leg./ 47 Sericini Asia spec.” ( ZFMK), 3 ♀♀ “ Laos centr., 5. -11. V .1997 20 km NW Louang Namtha N21°09.2’, E 101°18.7’, alt. 900m + 100m E. Jendek & O. Šauša leg.” (2 ♀♀ CP, 1 ♀ ZFMK) .

Description of the holotype. Length: 7.5 mm, length of elytra: 5.2 mm, width: 4.2 mm. Body oval, dark yellowish brown; midline, scutellum, and elytral striae yellowish brown, frons, sutural and odd intervals, and two spots on each side of pronotum as well its margins dark brown with greenish shine, dorsal surface dull, labroclypeus simply shiny; dorsal surface almost evenly and moderately densely covered with minute setae, with white, robust, erect setae on elytra.

Labroclypeus subtrapezoidal and moderately short, widest at base, lateral margins convex and strongly 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, anteriorly narrowly shiny, glabrous with fine and moderately dense punctures, beside eyes with a few long erect setae. Eyes small, ratio of diameter/ interocular width: 0.56. Antenna yellow, with ten antennomeres; club with four antennomeres subequal in length, club as long as remaining antennomeres combined. Mentum weakly convexly elevated anteriorly.

Pronotum wide, widest at base, lateral margins strongly curved and convergent anteriorly, anterior angles moderately produced and acute, posterior angles convex; 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; anterior and lateral borders sparsely setose; hypomeron carinate, its basal margin not produced ventrally. Scutellum narrow and short, apex weakly rounded, with fine and dense punctures along lateral margins, impunctate along midline, with minute setae in punctures.

Elytra short oval, widest at middle, striae finely impressed and finely densely punctate, intervals moderately convex and finely punctate, punctures concentrated long striae, throughout with minute setae in punctures, with a few long scale-like white setae on odd intervals, and on posterior half with moderately dense smaller white setae; 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, with a rim of short microtrichomes.

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/ 1.33. Pygidium yellow, strongly convex, with fine and dense punctures bearing fine white setae, with numerous robust and erect yellowish setae, 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, dorsal and ventral margin almost subparallel, ratio width/ length: 1/ 3.7, dorsally longitudinally convex, with two groups of spines, the basal group at one third, 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, before the basal group of spines with an undulated serrated line; ventral edge 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. 2 A–C.

Female: Antennal club short as in male, composed of three antennomeres; pygidium shiny, flat, nearly impunctate.

Diagnosis. Microserica ventrosa new species differs from all other species of the Microserica lineata group by the ventral lamina of left side of phallobase which is strongly produced ventrally, the phallobase results distally strongly widened.

Etymology. The name of the new species (adjective in nominative case) is derived from the Latin adjective ventrosa (large belly), with reference to the ventrally strongly expanded lateral lamina of the phallobase.

Variation. Length: 6.7–7.5 mm, length of elytra: 4.7–5.2 mm, width: 4.0– 4.2 mm.

Figures

FIGURES 2A–F. A–D, Microserica ventrosa Bohacz & Ahrens, new species (holotype); E–H, M. ginae Bohacz & Ahrens, 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.