Microserica planiforceps 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 : 57-58

Microserica planiforceps Ahrens, Lukic & Liu, new species

Figs. 19A–D , 32

Type material examined. Holotype: Ô “N-Thailand 14.-28.VIII.1990 Doi Inthanon lg. Malicky / Zoologische Staatssammlung München / 40 Sericini Asia spec.” ( ZSM) . Paratypes: Thailand: 20 ÔÔ, 7 ♀♀ “N-Thailand 14.- 28.VIII.1990 Doi Inthanon lg. Malicky / Zoologische Staatssammlung München” ( ZSM, ZFMK) , 9 ÔÔ, 7 ♀♀ “N-Thailand 27.III.-3.IV.1990 Doi Inthanon lg. Malicky / Zoologische Staatssammlung München” ( ZSM, ZFMK) , 5 ÔÔ, 1 ♀ “N-Thailand 10.-12.IV.1990 Doi Inthanon lg. Malicky / Zoologische Staatssammlung München” ( ZSM, ZFMK) , 2 ÔÔ “N-Thailand 12-14.V.1990 Doi Inthanon lg. Malicky / Zoologische Staatssammlung München” ( ZSM) , 1 Ô “ LAOS, 21°09’N 101°19’E Louangnamtha pr., Namtha -> Muang Sing , 5-31.v.1997, 900-1200 m Vit Kubáň leg. / LS 38” ( CP) , 3 ÔÔ “NW Thailand, 19.19N 97.59E Mae Hong Son 1991 Ban Huai Po , 1600-2000m, 17.-23.5. L. Dembicky ” ( NHMW) , 11 ÔÔ “W. Thailand: 300m, Thung Yai Wildlife Sanctuary, 15°28’N – 98°48’E / Kanchaburi Prov., Sankhla Buri Dist. Mae Kasa Stream. iv/ v.1988 / M.J.D. Brendell B.M. 1988-183” ( BMNH) , 1 Ô “W. Thailand: 300m, Thung Yai Wildlife Sanctuary, 15°28’N – 98°48’E / Tak Province Umphang District Song Bae Stream. 18-27.iv.1988 / M.J.D. Brendell B.M. 1988-183” ( BMNH) . Laos: 1 Ô “ LAOS north, 4.V.1997 Louang Namtha env. N 21°00.3, E 101°24.6., E. Jendek & O. Sausa leg.” ( CP) .

Description of holotype. Length: 3.6 mm, length of elytra: 2.6 mm, width: 2.3 mm. Body oval, body yellowish brown, lateral and sutural elytral intervals and frons brown, dorsal surface dull and nearly glabrous.

Labroclypeus subtrapezoidal, little wider than long, widest at base, lateral margins convex and convergent to moderately rounded anterior angles; anterior margin weakly emarginate medially, margins weakly reflexed; lateral margins and ocular canthus produce a blunt angle; surface shiny, flat, finely, densely punctate, with two long, erect setae on each side; frontoclypeal suture finely incised and curved, short, as long as smooth area in front of eye. Frons dull, with sparse, fine punctures, beside eyes with two single setae, otherwise glabrous. Smooth area in front of eyes large, mesally strongly enlarged, convex, 1.2 times as wide as long. Ocular canthus impunctate, narrow and short (1/4 of ocular width), with a terminal seta. Eyes moderately large, ratio of diameter/interocular width: 0.64. Antenna with ten antennomeres; club composed of five antennomeres, strongly reflexed, three times as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum wide, widest at base, lateral margins in basal half straight and weakly convergent, in anterior third convex and moderately convergent to moderately produced and blunt anterior angles, posterior angles blunt.Anterior margin of pronotum straight, with fine and complete marginal line; basal marginal line absent; surface finely and densely punctate, with minute setae in punctures, lateral margin sparsely setose, anterior margin glabrous. Hypomeron distinctly carinate, carina not ventrally produced. Scutellum large, triangular, finely and densely punctate.

Elytra short oval, widest at posterior third, striae finely impressed, finely and densely punctate, intervals weakly convex, with fine and moderately dense punctures concentrated along striae, with minute setae in punctures, otherwise glabrous; epipleural edge robust, ending at slightly rounded external apical angle of elytra, epipleura densely setose; apical border broadly membraneous (visible at ca 100x magnification).

Ventral surface dull, finely and densely punctate, metasternum sparsely covered with fine, short, or very minute setae; metacoxa glabrous, with numerous long, yellow, and robust setae laterally. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/2.3. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium weakly convex and dull, with fine, dense punctures, without smooth midline, with minute setae in punctures and numerous long robust setae along apical margin.

Legs moderately wide; femora finely and sparsely punctate, with two longitudinal rows of longer setae. Metafemur dull, anterior margin acute, with fine and continuous submarginal serrated line; anterior row of setabearing punctures reduced; ventral posterior margin strongly widened in apical half, smooth, dorsal posterior margin also smooth, with a few short setae basally. Metatibia moderately long and narrow, widest at middle, ratio width/ length: 1/2.47; dorsal margin sharply carinate, with two groups of spines, basal group at two thirds, apical one at four fifths of metatibial length, basal to the first group over the entire length with a fine and straight, serrated carina, beside which are a few single and short setae; lateral face flat, finely and densely punctate, with minute setae in punctures; ventral margin carinate and finely serrate, with three robust equidistant setae; medial face smooth, apex interiorly near tarsal articulation bluntly truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally with a few single fine punctures; metatarsomeres glabrous ventrally, with a strongly serrated ridge ventrally and a parallel subventral smooth carina immediately beside it; first metatarsomere as long as following two tarsomeres combined, almost twice as long as dorsal tibial spur. Protibia moderately long, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 19A–C . Habitus: Fig. 19D .

Diagnosis. Microserica planiforceps Ahrens, Lukic & Liu, new species is in external appearance rather similar to Microserica neosimplex Ahrens, Lukic & Liu, new species However, Microserica planiforceps Ahrens, Lukic & Liu, new species differs from this and all other species by the presence of a serrated longitudinal carina in the metatibia and beside the anterior margin of metafemur and as well as by the dorsoventrally flattened parameres.

Etymology. The species name is derived from the combined Latin words, “ planus ” (flat) and “ forceps ” (forceps) (adjective in nominative case), with references to the dorsoventrally flattened aedeagus including parameres.

Variation. Length: 3.6–4.5 mm, length of elytra: 2.6–3.5 mm, width: 2.3–3.0 mm. Female: slightly larger in general than males, eyes smaller, ratio of diameter/interocular width: 0.57; pygidium flat, antennal club short, composed of three antennomeres, distinctly shorter than remaining antennomeres combined.

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