Microserica septemfoliata ( Frey, 1972 ) Ahrens & Liu & Lukic & Bai, 2023

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 : 58-59

Microserica septemfoliata ( Frey, 1972) new combination

Figs. 19E–I , 32

Trichoserica septemfoliata Frey, 1972: 203 .

Type material examined. Holotype: Ô “ Dalat , 1966 S. Vietnam / Type Ophthalmoserica septemfoliata G. Frey 1971 ” ( CF / NHMB).

Redescription of the holotype. Length: 4.7 mm, length of elytra: 3.0 mm, width: 2.5 mm. Body oblong oval, yellowish brown; antenna yellow; frons, small spots elytral intervals, and two large spots on each side of pronotum darker brown; dorsal surface dull, labroclypeus and anterior frons simply shiny; dorsal surface almost glabrous.

Labroclypeus subrectangular and narrow, widest in anterior third, lateral margins subparallel straight and weakly convergent basally, anterior angles convex, lateral border and ocular canthus produce a distinct blunt angle, anterior and lateral margins moderately reflexed, anterior margin weakly emarginate medially; surface flat, finely and densely punctate, with a few erect setae; frontoclypeal suture short, only one quarter of clypeal width, finely impressed and weakly curved; smooth area in front of eye very large, 1.5 times as wide as long; ocular canthus long and narrow, impunctate, without a terminal seta. Frons posteriorly dull, anteriorly shiny, with fine and moderately dense punctures and with a few long setae on disc and sides. Eyes very large, ratio of diameter/interocular width: 0.93. Antenna yellow, with ten antennomeres; club with seven antennomeres equal in length, strongly reflexed, club 3.5 times as long as remaining antennomeres combined. Mentum weakly convexly elevated anteriorly.

Pronotum narrow, widest at middle, lateral margins anteriorly curved and convergent anteriorly, in posterior half straight but convergent towards blunt posterior angles, anterior angles moderately produced and blunt; anterior margin weakly convex medially, with a distinct and fine marginal line; basal margin without marginal line; surface with dense and fine punctures, with minute setae in punctures, otherwise glabrous on disc; anterior and lateral borders sparsely but robustly setose; hypomeron carinate, its basal margin weakly produced ventrally. Scutellum narrow and short, with fine, irregular, and moderately dense punctures, with minute setae in punctures.

Elytra oblong oval, widest at middle, striae well impressed and finely densely punctate; intervals finely punctate, punctures concentrated long striae, odd intervals convex, even intervals weakly convex, throughout with minute setae in punctures, penultimate lateral interval with a single robust long setae before apical quarter; interior apical angle of elytron with a robust seta; epipleural edge robust but convex, ending at strongly convex external apical angle of elytra; epipleura sparsely setose, apical border membraneous, with a fine rim of 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, otherwise almost glabrous except partly minute setae in punctures. Mesosternum between mesocoxae almost as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.5. Pygidium moderately convex, dull, with fine and dense punctures, without smooth midline, with longer setae along on apical half.

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, without adjacent continuously serrated line; posterior margin weakly convex and glabrous, ventrally weakly widened in apical half and distinctly serrate, posterior margin dorsally also finely serrate. Metatibia moderately slender and long, widest at apical third, ratio width/length: 1/3.5, dorsally sharply carinate, with one group of spines at five sixths of metatibial length, basally with a few single spines; with a straight and continuous serrated line from base to group of spines; lateral face weakly convex, with moderately dense and coarse punctures,, punctures with minute setae or with a few short, robust setae; ventral margin carinate and serrated, with three robust spines of which the distal is more distant; medial face impunctate and smooth, apex interiorly (near tarsal articulation) distinctly truncate. Tarsomeres dorsally glabrous and sparsely finely punctate, ventrally with a sparse, short setae; metatarsomeres dorsally carinate, with fine punctures bearing short setae, ventrally with a single strongly serrated carina, adjacent subventral carina present, but interiorly; first metatarsomere distinctly shorter than following two tarsomeres combined and twice as long as dorsal metatibial spur. Protibia short, bidentate, protarsal claws symmetrical.

Aedeagus: Figs. 19E–H . Habitus: Fig. 20I . Female unknown.

Remarks. Despite the labelling on the holotype, the species was originally treated by Frey (1972) as a Triochoserica species. The systematic placement of this species is uncertain. Its morphology, particularly the serrated metatibia, the divergent genital morphology, and the constitution of the antenna are not retrieved in any other species of Microserica . Some affinities even with the species of the Neoserica calva group exist. However, given the reported strong homoplasy of the serrated metatibia in several other Sericini lineages and its considerable variation within some of these (e.g., Ahrens 2006; Bohacz & Ahrens 2020) but also of the number of antennomeres composing the antennal club, we do not see very strong arguments for a robust classification of this species, neither to erect an independent genus for it at this moment.

Figures

FIGURE 19. A–D: Microserica planiforceps Ahrens, Lukic & Liu, new species (holotype); E–I: Mic. septemfoliata (Frey, 1972) new combination (holotype). A, E: Aedeagus, left side lateral view; C, H: Aedeagus, right side lateral view; B, F: Parameres, dorsal view; G: Parameres, basidorsal view; D, I: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 20.A–E: Moronoserica squamulatoidesAhrens, Lukic & Liu, new species (holotype); F–J: Mor. banmethout Ahrens, Lukic & Liu, new species (holotype); K–O: Mor. renong Ahrens, Lukic & Liu, new species (holotype). A, F, K: Aedeagus, left side lateral view; D, I, N: Aedeagus, right side lateral view; C, H, M: Parameres, dorsal view; B, G, L: Phallobase, dorsal view; E, J, O: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 32. Distribution of the Oxyserica marginata group (excluding the Himalayan Oxyserica species, shown in Ahrens & Fabrizi 2016) and of Microserica (sensu lato) species.