Tetraserica semikontumensis Pham & Ahrens, 2023

Ahrens, Dirk, Lukic, Daniel, Pham, Phu, Li, Wei & Liu, Wangang, 2023, Tetraserica Ahrens, 2004 of continental Southeast Asia: new records, new species and an updated key to species (Coleoptera: Scarabaeidae: Sericinae: Sericini), Zootaxa 5374 (4), pp. 451-486 : 470-471

Tetraserica semikontumensis Pham & Ahrens , new species

Fig. 7E–H

Type material examined. Holotype: ♂ “[ Vietnam] Quang Nam Pro., Song Thanh Dis., Cha Vai ; 27.v.2005; light trap; 350m ” ( IEBR) . Paratype: 1 ♂ “[ Vietnam] Quang Nam Pro., Song Thanh Dis., Cha Vai ; 27.v.2005; light trap; 350m ” ( IEBR) .

Description of the holotype. Length: 9.3 mm, length of elytra: 6.9 mm, width: 6.4 mm. Body oval, reddish brown, labroclypeus and dorsal surface shiny, glabrous.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins moderately convex, anterior angles strongly convex, anterior margin slightly emarginate medially; lateral margin and ocular canthus producing a blunt angle, margins moderately reflexed; surface slightly convex medially, shiny, moderately and densely punctate, without setae; frontoclypeal suture moderately impressed and strongly curved medially; smooth area in front of eye three times as wide as long; ocular canthus moderate and triangular(1/3 of ocular diameter), weakly punctate, without setae. Frons moderately shiny and smooth, bearing only a single erect setae beside eyes. Eyes small, ratio of diameter/ interocular width: 0.55.

Antenna yellowish brown, with ten antennomeres, club in male with four antennomeres, slightly longer than remaining antennomeres combined, first joint of club as long as club. Mentum anteriorly weakly elevated and weakly convex in middle.

Pronotum transverse, widest just before base, lateral margins moderately convex and evenly convergent anteriorly, anterior angles distinctly produced, posterior angles strongly convex. Anterior margin slightly convex medially, with a fine, complete marginal line. Surface densely and finely punctate, with minute setae in punctures; lateral margins sparsely setose. Hypomeron not carinate. Scutellum triangular, with fine and dense punctures.

Elytra oblong, widest at posterior third, striae weakly impressed, finely and densely punctate, intervals weakly convex, with fine, dense punctures, punctures with minute setae; epipleural edge moderately robust, ending at convex external apical angle of elytra, epipleura sparsely setose, apical border membraneous, with a rim of short microtrichomes.

Ventral surface dull, reddish brown, with large and dense punctures, sparsely setose; metasternum sparsely covered with fine, short, or minute setae; metacoxa glabrous, with a few single setae laterally; abdominal sternites finely and densely punctate, with a transverse row of coarse punctures each bearing a robust seta. Mesosternum between mesocoxae nearly as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/1.47. Pygidium moderately convex and dull, coarsely densely punctate, without smooth midline, with some erect setae.

Legs moderately wide; femora with two longitudinal rows of setae, finely and moderately densely punctate; metafemur wide, moderately shiny, its anterior margin acute, lacking an adjacent serrated line; ventral posterior margin straight, smooth and slightly widened in apical half; dorsal posterior margin smooth, without moderate short setae basally. Metatibia moderately short, widest at middle; ratio width/ length: 1/3.2; dorsal margin weakly longitudinally convex, with two groups of spines, basal one at first third, apical one at two thirds of metatibial length, basally with a few short single setae; lateral face weakly finely punctate; ventral margin finely serrate, with four robust equidistant setae; medial face smooth; apex interiorly near tarsal articulation moderately concave. Tarsomeres in distal half with fine, dense setae ventrally, dorsally smooth; metatarsomeres with a strong serrated ridge and glabrous ventrally, first metatarsomere as long as following two tarsomeres combined, longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus. Fig. 7E–G . Habitus: Fig. 7H . Female unknown.

Diagnosis. Tetraserica semikontumensis Pham & Ahrens , new species differs from the similar T. kontumensis Fabrizi, Dalstein & Ahrens, 2019 by having the dorsal hook of the distinctly larger basal lobe of the left paramere much longer and more strongly curved; the basal lobe of right paramere is more robust in the new species and the apical phallobasal lamina is distinctly shorter, not exceeding the dorsal lobe of the left paramere.

Variation. Length of body: 9.3–10.0 mm; length of elytra: 6.9 –7.5 mm; maximum width: 6.4 –6.7 mm.

Etymology. The species name (adjective in the nominative singular) is derived from the combined Latin prefix semi - (half) and the species name kontumensis, with reference to the similarity of this species to T. kontumensis .

Figures

FIGURE 7. A–D: Tetraserica phamanhi Pham & Ahrens, new species (holotype); E–H: T. semikontumensis Pham & Ahrens, new species (holotype). A, E: aedeagus, left side lateral view; B, F: parameres, dorsal view; C, G: aedeagus, right side lateral view; D, H: habitus. Scale: 0.5 mm. Habitus not to scale.