Neoserica champassakensis Ahrens, 2022

Ahrens, Dirk, 2022, New Gynaecoserica Brenske, 1897 species and further new bicolored species of the Neoserica calva group (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5165 (2), pp. 180-190 : 184-185

Neoserica champassakensis Ahrens , new species

Fig. 2A–D

Type material examined. Holotype: ♂ “ LAOS, Champassak Prov., Dong Hua Yao NBCA, 2 km S of Ban Nong Luang, bank of Touay-Guai stream / 15°4'N, 106°13'E, 800 m, at light, No. 24. 1-5.IV.1998, leg. O. Merkl & G. Csorba / 1127 Sericini Asia spec.” ( HNHM) . Paratypes: 2 ♀♀ “ LAOS, Champassak Prov., Dong Hua Yao NBCA, 2 km S of Ban Nong Luang, bank of Touay-Guai stream / 15°4'N, 106°13'E, 800 m, at light, No. 24. 1-5.IV.1998, leg. O. Merkl & G. Csorba ” ( HNHM, ZFMK) .

Description of the holotype. Body length: 4.0 mm, length of elytra: 2.4 mm, width: 2.4 mm. Body short-oval, brown, dull tomentum of pronotum somewhat grey, antennal club and legs as well as a large spot on disc of elytra and posterior pronotum yellowish brown, dorsal surface dull and nearly glabrous, labroclypeus and anterior third of frons shiny.

Labroclypeus semicircular, distinctly wider than long; lateral margins convex and strongly convergent anteriorly; anterior angles almost blunt but moderately rounded at tip; anterior margin shallowly emarginate medially; margins strongly reflexed; surface distinctly elevated medially and shiny, finely and densely punctate, with a few single setae anteriorly and on sides. Frontoclypeal suture indistinct, strongly curved. Smooth area anterior to eye convex, as wide as long. Ocular canthus moderately long and wide (equal to 1/3 of ocular diameter), finely and densely punctate, with a single terminal seta. Frons on anterior third shiny, finely and irregularly densely punctate, with a few long single setae beside eyes, otherwise glabrous; on posterior two thirds dull, finely and densely punctate, with moderately dense, short setae. Eyes small, ratio diameter/interocular width: 0.6. Antenna with ten antennomeres, club with four antennomeres, straight and as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly. Labrum transverse, short, not produced medially, with weak median sinuation.

Pronotum transverse, widest at base; in basal half lateral margins moderately convex and weakly convergent anteriorly, in anterior half margins strongly convex and convergent; anterior angles produced and sharp; posterior angles blunt; anterior margin with a fine complete marginal line, weakly convexly produced medially; surface densely and coarsely punctate, with minute setae in punctures; lateral and anterior border sparsely setose; basal margin without marginal line; hypomeron distinctly carinate basally. Scutellum long, with fine, dense punctures, and minute setae in punctures.

Elytra short oval, widest at posterior third; striae weakly impressed, finely and moderately densely punctate; intervals flat, with sparse, fine punctures mainly concentrated along striae, with minute setae in punctures. Epipleural edge fine, ending at moderately curved external apical angle of elytra; epipleura densely setose; apical border with a fine rim of microtrichomes (visible at 100x magnification).

Ventral surface dull, finely and densely punctate. Metasternum except long setae on disc nearly glabrous, sparsely covered with minute setae in punctures. Metacoxa glabrous, with a few single setae laterally. Abdominal sternites finely and densely punctuate, glabrous except minute setae in punctures, with a transverse row of coarse punctures each bearing a robust long seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.16. Pygidium moderately convex and dull, coarsely and densely punctate, without smooth midline, with short adpressed, partly only minute setae in punctures, beside apical margin with longer setae.

Legs moderately slender. Femora with two longitudinal rows of setae, finely and sparsely punctate. Metafemur dull and sparsely finely punctate; anterior margin acute, behind anterior margin without serrated line; posterior ventral margin in apical half not serrated and moderately widened at apex; posterior dorsal margin finely serrated, glabrous. Metatibia slender and short, widest at apex, ratio of width/length: 1/3.1; dorsal margin sharply carinate, with two groups of spines; basal group at first third, apical group at two thirds of metatibial length; basally with a single fine seta but without serrated longitudinal margin; lateral face longitudinally convex, finely and sparsely punctate; ventral margin finely serrated, with three robust setae, with the apical one being more distant; medial face impunctate, glabrous, apex concavely moderately deeply truncate interiorly near tarsal articulation. Tarsomeres ventrally with sparse, short setae, not carinate laterally, impunctate dorsally; metatarsomere 1 almost twice as long as dorsal metatibial spur and little shorter than following two tarsomeres combined. Protibia short, bidentate, not widened laterally before basal tooth; anterior claws symmetrical, basal tooth of inner claw sharply truncate at apex.

Aedeagus: Fig. 2A–C . Habitus: Fig. 2D .

Diagnosis. Neoserica champassakensis Ahrens , new species differs from N. rufoplagiatoides Ahrens & Pham, 2021 , the only other bicolored species of the N. calva group, by parameres being almost subequal in total length, and which both are being straight and have distinct basal lobes.

Variation. Body length: 4.0– 4.1 mm, length of elytra: 2.4–2.5 mm, width: 2.4–2.5 mm. Female: Eyes as small as in male; antennal club composed of three short lamellae, club little shorter than remaining antennomeres combined; light spots on elytra more extended than in male, reducing the dark parts to the margins; pygidium moderately convex.

Etymology. Named after its occurrence in the Champassak province (adjective in nominative singular case).

Figures

FIGURE 2. A–D: Neoserica champassakensis Ahrens, new species (holotype); E–H: N. fairyqueen Ahrens, new species (holotype); I–L: N. samuelsoni 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.