Tetraserica quangtri Ahrens, Pacholátko & Pham, 2025

Tetraserica quangtri Ahrens, Pacholátko & Pham View in CoL , sp. nov.

Fig. 3A–F View FIGURE 3

Type material examined. Holotype ♂ “VS24-0066 / VIETNAM: Quang Tri Pro., Bac Huong Hoa NR-UV1- behind guest house, 11.v.2024, P.V. Pham leg.” ( IBHV) . Paratype: 1 ♂ “VS24-0185 / VIETNAM: Quang Tri Pro., Bac Huong Hoa NR, UV6-up to the hill, 10.v.2024, P.V. Pham leg.” ( ZFMK) .

Description of holotype. Length: 9.0 mm; length of elytra: 7.4 mm; maximum width: 6.2 mm. Body oval, dorsal surface dark reddish brown and glabrous, frons and pronotum with weak greenish shine, labroclypeus, ventral surface and legs reddish brown, 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 twice 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, 1.2 times as long as remaining antennomeres combined. Eyes moderately large, ratio of diameter/interocular width: 0.62. 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, on odd intervals moderately concentrated along striae, with very minute setae in punctures; 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: 1/1.45. Pygidium moderately convex in apical half and dull, densely punctate, without smooth midline, almost glabrous, with numerous longer setae along apical margin.

Legs wide; femora finely and sparsely punctate; metafemur wide and moderately shiny, anterior margin acute, posterior margin smooth ventrally and only weakly widened in apical half, posterior margin smooth dorsally, straight and glabrous. Metatibia moderately short and wide, widest at middle; ratio width/length: 1/2.4; basal group of dorsal spines of metatibia at first third, apical one at three quarters of metatibial length; ventrodistal margin strongly truncated, ventral margin one quarter of its length shorter than dorsal one, ventral terminal spine very long, as long as metatibia, and strongly curved. Tarsomeres dorsally smooth, with fine, dense setae ventrally on distal half, neither laterally nor dorsally carinate; metatarsomeres with a strongly serrated ridge ventrally and glabrous; first metatarsomere as long as following two tarsomeres combined, a quarter 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. 3A–D View FIGURE 3 . Habitus: Fig. 3E, F View FIGURE 3 . Female unknown.

Variation. Length: 9.0– 10.6 mm; length of elytra: 7.4–8.1 mm; maximum width: 6.2–6.3 mm.

Diagnosis. The species is most similar to T. bachmaensis Fabrizi, Dalstein & Ahrens, 2019 , both species share the extremely elongate ventral metatibial spine and the ventroapically truncate metatibia ( Fig. 3E View FIGURE 3 ). Tetraserica quangtri Ahrens, Pacholátko & Pham , sp. nov. differs mainly by the shape of right paramere of which the dorsal lobe is strongly curved and of which the apex is ending well distant from that of the ventral lobe (lateral view); the ventral love somewhat longer and strongly curved in apical half rather than being almost straight as in T. bachmaensis .

Etymology. The name of the new species is derived from its occurrence in Quang Tri Province (noun in apposition).