Oxyserica serena 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 : 79-80

Oxyserica serena Ahrens, Lukic & Liu, new species

Figs. 23E–H , 32

Type material examined. Holotype: Ô “ Myanmar N (Burma) 25 km E Putao, H= 800 m Nan Sa Bon vill. 06- 09.05.1998 leg. S. Murzin & V. Sinaev ” ( ZFMK).

Description of holotype. Length: 4.7 mm, length of elytra: 3.2 mm, width: 3.2 mm. Body short-oval, light reddish brown, elytra and antennal funiculus yellowish brown, head, antennal club, elytral margins and one transversal mesolateral spot dark brown, dorsal surface dull, nearly glabrous.

Labroclypeus trapezoidal, distinctly wider than long, shiny, widest at base, lateral margins weakly convex and strongly convergent to weakly convex, blunt anterior angles; anterior margin weakly emarginate medially, margins moderately reflexed; lateral margins and ocular canthus produce an indistinct angle; surface convex, finely and densely punctate, with a few long, erect setae; frontoclypeal suture finely incised and curved medially. Frons anteriorly narrowly shiny, with dense, fine punctures, beside eyes with some long setae, otherwise glabrous. Smooth area in front of eyes convex, as wide as long. Ocular canthus narrow and short (1/4 of ocular diameter), almost impunctate, with a terminal seta. Eyes very small, ratio of diameter/interocular width: 0.38. Antenna with ten antennomeres; club composed of four antennomeres, straight, 1.1 times as long as than remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum wide, widest at base, lateral margins evenly and moderately convex and convergent towards sharp and produced anterior angles; posterior angles blunt. Anterior margin of pronotum straight, with fine but medially widely interrupted marginal line; basal marginal line absent; surface finely and densely punctate, with minute setae in punctures; setae of lateral and anterior margins sparse, not extending on pronotal disc around anterior angles. Hypomeron carinate, weakly produced ventrally. Scutellum triangular, finely and densely punctate, glabrous.

Elytra short, widest at middle, striae weakly impressed, finely and sparsely punctate; sutural interval and epipleura dark, behind middle with a large dark spot from external margin to 5 th interval; intervals flat, with fine and sparse punctures, with minute setae in punctures, penultimate lateral interval with a few short setae; epipleural edge fine, ending at weakly rounded, and almost blunt external apical angle of elytra, epipleura sparsely setose; apical border chitinous, without a rim of microtrichomes (magnification 100x).

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: 1/1.67. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium moderately convex and dull, with dense, coarse punctures but without smooth midline, with minute setae in punctures, with a few longer setae along apical margin.

Legs short and 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; posterior margin smooth ventrally, not serrate, strongly widened in apical half, posterior margin smooth dorsally, with a few short setae basally. Metatibia moderately long and wide, widest at middle, ratio of width/length: 1/2.7; dorsal margin weakly carinate, with two groups of spines, basal group at one third, apical one at two thirds of metatibial length, in basal third without further robust setae; lateral face longitudinally convex, finely and sparsely punctate, sometimes with minute setae in punctures; ventral edge finely serrate, with three robust equidistant setae; medial face smooth, apex interiorly near tarsal articulation shallowly concavely truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally smooth; 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, distinctly longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 23E–G . Habitus: 23H.

Diagnosis. Oxyserica serena Ahrens, Lukic & Liu, new species resembles in external appearance Oxyserica pygidialis Brenske, 1900 , however, the aedeagus is not completely symmetric as in the Oxyserica species group around O. pygidialis . In fact, morphology of aedeagus it more similar to the three previous species, O. nigropicta ( Fairmaire, 1891) , O. diversicornis ( Moser, 1915) , and O. bifascipennis Ahrens, Lukic & Liu, new species which differs from all the species of the Oxyserica marginata group by the subsymmetric ventral lobes of parameres.

Etymology. The name of the new species is derived from the combined Latin adjective “ serenus ” (light).

Figures

FIGURE 23. A–D: Oxyserica bifascipennis Ahrens, Lukic & Liu, new species (holotype); E–H: O. serena 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 32. Distribution of the Oxyserica marginata group (excluding the Himalayan Oxyserica species, shown in Ahrens & Fabrizi 2016) and of Microserica (sensu lato) species.