Oxyserica bifascipennis 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 : 78-79

Oxyserica bifascipennis Ahrens, Lukic & Liu, new species

Figs. 23A–D , 32

Type material examined. Holotype: Ô “Birmah Ruby Mes. / Doherty / Fry Coll. 1905.100. / 896 Asia Sericini spec.” ( BMNH) . Paratypes: 1 Ô, 1 ♀ “ Hte Birmanie Mines des Rubies 1200-2300m Doherty 1890 / Museum Paris ex. Coll. R. Oberthur ” ( MNHN, ZFMK) .

Description of holotype. Length: 7.2 mm, length of elytra: 5.4 mm, width: 4.4 mm. Body oblong-oval, dark reddish brown, elytra and antennal funiculus yellowish brown, elytral margins and one transversal mesolateral spot dark brown, dorsal surface dull or partly with iridescent shine, nearly glabrous.

Labroclypeus little wider than long, shiny, widest at base, lateral margins strongly convex and convergent to convex anterior angles; anterior margin deeply emarginate medially, margins moderately reflexed; lateral margins and ocular canthus produce a blunt angle; surface convex, coarsely and densely punctate, with numerous long, erect setae; frontoclypeal suture finely incised and curved medially. Frons entirely shiny, with irregularly dense, fine punctures, beside eyes with some long setae, otherwise glabrous. Smooth area in front of eyes flat, twice as wide as long. Ocular canthus narrow and moderately long (1/3 of ocular diameter), almost impunctate, with a terminal seta. Eyes moderately large, ratio of diameter/interocular width: 0.73. Antenna with ten antennomeres; club composed of four antennomeres, straight, as long as than remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately wide, widest at base, lateral margins in basal half straight and distinctly convergent, anteriorly moderately convex and convergent towards sharp and produced anterior angles; posterior angles blunt. Anterior margin of pronotum weakly convex, with fine but medially widely interrupted marginal line; basal marginal line absent; surface finely and densely punctate, glabrous, 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 elongate, widest at middle, striae weakly impressed, finely and densely punctate; sutural interval and lateral 2–3 intervals dark, dark color on elytra on mesal intervals near scutellum extended, as behind middle on sublateral intervals; intervals weakly convex, 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 narrowly membranous, with a fine rim of short 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: 1/1.59. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium weakly convex and dull, with dense, coarse punctures but without smooth midline, with a few longer setae along apical margin.

Legs almost slender and long; 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, 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: 1/3.55; dorsal margin weakly carinate in apical half, in basal half longitudinally convex, with two groups of spines, basal group at shortly before middle, apical one at three quarters 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 little shorter than 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. 23A–C . Habitus: 23D.

Diagnosis. Oxyserica bifascipennis Ahrens, Lukic & Liu, new species resembles in external appearance the O. marginata ( Brenske, 1898) , while in shape of aedeagus it is similar to O. nigropicta ( Fairmaire, 1891) and O. diversicornis ( Moser, 1915) . Oxyserica bifascipennis Ahrens, Lukic & Liu, new species differs from all of them by the larger body size, and, of course, in shape of parameres: the distal margin of phallobase (lateral view) is reflexed, the ventral lobes of parameres which are in the new species as well as in O. nigropicta and O. diversicornis subsymmetric, are longer than half of the phallobase in Oxyserica bifascipennis .

Etymology. The name of the new species is derived from the combined Latin prefix “ bi ” (two-), and the words “ fascis ” (stripes) and “ pennis ” (wing).

Variation. Length: 7.0– 7.2 mm, length of elytra: 5.1–5.4 mm, width: 4.3–4.4 mm. Female: Antennal club composed of three antennomeres, little shorter than the remaining antennomeres combined.

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.