Tetraserica yongbelar Ahrens, new species

Fig. 1F–I

Type material examined. Holotype: ♂ “X-DA6792 Malaysia Pahang, Cameron Highl. Yong Belar 4.62873°N, 101.39481°E 1710m leg. M3B 21.3.2006 Tetraserica sp. TigerThai201/ 1170 Sericini Asia spec.” (ZFMK).

Description of the holotype. Length: 9.9 mm; length of elytra: 7.4 mm; maximum width: 5.0 mm. Dorsal surface dark brown and glabrous, ventral surface reddish brown, femora and antenna yellow.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins moderately convex and convergent to strongly rounded anterior angles, anterior margin weakly emarginate medially, margins moderately reflexed; surface weakly convex, moderately shiny, finely and densely punctate, glabrous; frontoclypeal suture indistinctly incised, flat and weakly curved medially; ocular canthus short and triangular, impunctate, with a single terminal seta. Smooth area anterior to eye 1.5 times as wide as long. Frons dull, with sparse, fine punctures, with two single erect setae beside each eye. Antenna yellowish, with ten antennomeres; club composed of four antennomeres in male, straight, 1.1 times as long as remaining antennomeres combined. Eyes small, ratio of diameter/interocular width: 0.57. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately wide and convex, widest shortly before base, lateral margins evenly convex, strongly narrowed anteriorly towards sharp and slightly produced anterior angles, posterior angles convex. Anterior margin of pronotum slightly convex, with fine, complete marginal line. Surface finely and densely punctate, except minute setae glabrous, lateral and lateral anterior margins sparsely setose. Hypomeron not carinate. Scutellum triangular, finely and densely punctate.

Elytra oblong, widest in posterior third, striae distinctly impressed, finely and moderately densely punctate, intervals flat, with fine and almost evenly dense punctures weakly concentrated along striae, with very minute setae in punctures and a very few short setae on odd intervals; epipleural edge robust, ending at convex external apical angle of elytra, epipleura densely setose; apical border with a narrow fringe of microtrichomes (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; abdominal sternites finely and densely punctuate, with a transverse row of coarse punctures, each bearing a robust seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.5. Pygidium flat and dull, densely punctate, without smooth midline, almost glabrous, with a few longer setae along apical margin.

Legs wide; femora finely and sparsely punctate; metafemur wide and moderately shiny or dull, anterior margin acute, posterior margin smooth ventrally and only weakly widened in apical half, posterior margin smooth dorsally, with a few short setae basally. Posterior margin of metafemur generally straight or slightly convex. Metatibia moderately long and quite narrow, widest at middle; ratio width/length: 1/3.1; basal group of dorsal spines of metatibia at first third, apical one at two thirds of metatibial length; ventral margin weakly convex and serrate, with three equidistant robust setae; apical margin bluntly and slightly concavely truncated towards ventral margin. Tarsomeres dorsally smooth, with fine, sparse setae ventrally, neither laterally nor dorsally carinate; metatarsomeres with a strongly serrated ridge ventrally and glabrous; first metatarsomere as long as following two tarsomeres combined, one third of its length longer than dorsal tibial spine. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 1F–H. Habitus: Fig. 1I. Female unknown.

Diagnosis. Tetraserica yongbelar Ahrens, new species differs from the similar to T. tanahrataensis Fabrizi, Dalstein & Ahrens, 2019, by the left paramere which is split much more basally (at 1/3 of its length) into two long, filiform branches; the distal portion of the right paramere (behind the median bent) is as long as the basal one, while in T. tanahrataensis the distal portion is much shorter than the basal part.

Etymology. The new species is named after its type locality, Yong Belar (noun in apposition).