Microserica chaiyaphum 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 : 52-53

Microserica chaiyaphum Ahrens, Lukic & Liu, new species

Figs 18 I-L, 29

Type material examined. Holotype: Ô “X-DA5202 / X- DA5202 Thailand Chaiyaphum Pha Hin Ngam NP Dry evergreen forest near stream 15°40.569’N, 101°26.705’E 461m leg. T2476 Katae Sa-nog & Buakaw Adnafai Malaise traps 7.-13.vi.2007 Microserica sp. TigerThai09 / 1172 Sericini Asia spec.” ( QSBG) . Paratypes: 1 Ô “XDA5201 / X- DA5201 Thailand Chaiyaphum Pha Hin Ngam NP Dry evergreen forest near stream 15°40.569’N, 101°26.705’E 461m leg. T2476 Katae Sa-nog & Buakaw Adnafai Malaise traps 7.-13.vi.2007 Microserica sp. TigerThai09” ( ZFMK) , 1 Ô “X-DA5200 / X- DA5200 Thailand Chaiyaphum Pha Hin Ngam NP Dry evergreen forest near stream 15°40.569’N, 101°26.705’E 461m leg. T2476 Katae Sa-nog & Buakaw Adnafai Malaise traps 7.-13.vi.2007 Microserica sp. TigerThai09” ( QSBG) , 1 Ô “X-DA5193 / X-DA5193 Thailand Chaiyaphum Pha Hin Ngam NP Deciduous forest 15°39.966’N, 101°27.198’E 357m leg. T2467 Katae Sa-nog & Buakaw Adnafai Pan traps 8.-9.vi.2007 Microserica sp. TigerThai09” ( QSBG) .

Description of holotype. Length: 5.2 mm, length of elytra: 3.5 mm, width: 3.1 mm. Body oval, dark brown, head and pronotum with some greenish shine, antenna yellow, dorsal and ventral surface dull but with iridescent shine; dorsal surface glabrous.

Labroclypeus trapezoidal, distinctly wider than long, widest at base, lateral margins weakly convex and convergent to strongly rounded anterior angles; anterior margin weakly emarginate medially, margins weakly reflexed; lateral margins and ocular canthus produce an indistinct blunt angle; surface shiny, weakly convex medially, coarsely and densely punctate, with a few short erect setae; frontoclypeal fine, weakly curved. Frons dull, with dense, fine punctures; with a few single setae beside eyes, otherwise glabrous. Smooth area in front of eyes flat, twice as wide as long. Ocular canthus wide and short (1/3 of ocular width), its external margin straight, impunctate, with a terminal seta. Eyes small, ratio of diameter/interocular width: 0.49. Antenna with ten antennomeres; club composed of four antennomeres, straight, 1.1 times as long as remaining antennomeres combined, all lamella of club equal in length. Mentum elevated and slightly flattened anteriorly.

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

Elytra oval, widest at middle, striae distinctly impressed, finely and densely punctate, intervals convex, with fine and dense punctures only concentrated along striae, along middle almost impunctate, with minute setae in punctures, odd intervals with a few single, short white, adpressed setae; epipleural edge fine, ending convex external apical angle of elytra, epipleura densely setose; apical border membraneous, with a fine fringe of short microtrichomes (visible at ca 100x magnification).

Ventral surface dull, finely and densely punctate, metasternum on disc with long erect setae, otherwise 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: 1/1.93. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a large, robust seta. Pygidium weakly convex and dull, with fine, dense punctures, without smooth midline, with a few long setae along apical margin, otherwise glabrous.

Legs moderately wide and long; femora finely and sparsely punctate, with two longitudinal rows of longer setae. Metafemur shiny, anterior margin acute, without submarginal serrated line; anterior row of seta-bearing punctures reduced; ventral posterior margin distinctly widened in apical half and entirely smooth, dorsal posterior margin also smooth, with a few short setae basally. Metatibia short and wide, widest at middle but only weakly narrowed towards apex, ratio width/length: 1/3.4; dorsal margin carinate, with two groups of spines, basal group at anterior third, apical one at three quarters of metatibial length, in basal third with a few fine, single setae; lateral face longitudinally convex, finely and sparsely punctate on dorsal and basal portion, glabrous; ventral margin finely serrate, with four equidistant setae; medial face smooth and glabrous, apex interiorly near tarsal articulation bluntly truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally smooth; metatarsomeres ventrally glabrous, with a strongly serrated ridge ventrally, but without parallel subventral smooth carina; first metatarsomere distinctly shorter than following two tarsomeres combined, little longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 18I–K Habitus: Fig. 18L . Female unknown.

Diagnosis. Microserica chaiyaphum Ahrens, Lukic & Liu, new species is very similar to Mic. viengvai Ahrens, Lukic & Liu, new species and Mic. namnao Ahrens, Lukic & Liu, new species. Microserica chaiyaphum Ahrens, Lukic & Liu, new species differs from both by the shape of parameres: the right one is even wider (lateral view) than that of Mic. namnao , while the left paramere is not triangular, but almost evenly wide as that of Mic. viengvai , however, its apex is not bifid as in the latter but evenly broadly rounded.

Etymology. The species name is named after its occurrence in the Chaiyaphum province (noun in apposition).

Variation. Length: 5.1–5.3 mm, length of elytra: 3.5–3.6 mm, width: 3.1–3.2 mm.

Figures

FIGURE 18. A–D: Microserica viengvai Ahrens, Lukic & Liu, new species (holotype), E–H: Mic. namnao Ahrens, Lukic & Liu, new species (holotype), I–L: Mic. chaiyaphum Ahrens, Lukic & Liu, 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.