Tetraserica yucheni Liu, Li & 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 : 461-463

Tetraserica yucheni Liu, Li & Ahrens , new species

Fig. 4A–F

Type material examined. Holotype: ♂ “ Mengdui Town, Zhenkang County, Lincang City , Yunnan Province, 27.V.2022, Zhao Yuchen , Lu Jinbo , Light Trap ” ( IZAS) . Paratypes: 1 ♂ “ Mengdui Town, Zhenkang County, Lincang City , Yunnan Province, 27.V.2022, Zhao Yuchen , Lu Jinbo , Light Trap ” ( IZAS) , 3 ♂♂, 2 ♀♀ “ Gao Shan Trough Village, Yao’an County, Chuxiong , Yunnan Province, 24.V.2022, Xu Rentao , light trap ” ( IZAS) , 1 ♂, 4 ♀♀ “ Fengwei Town, Zhenkang County, Lincang City , Yunnan Province, 26.V.2022, Lu Jinbo , light trap ” ( IZAS) , 2 ♂♂ “ CHINA: Yunnan Prov. Lushui Co., Liuku city (park) Secondary broadleaved forest 25°51’.1’N, 98°51.1’E, 885 m Hájek, Hrůzová, Král, Růzička & Sommer lgt. 28.–30.vi.2019 ” ( NMPC, ZFMK) .

Description of the holotype. Length: 9.9 mm, length of elytra: 7.0 mm, width: 5.4 mm. Body oval, dark reddish brown, labroclypeus and dorsal surface shiny, glabrous.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins weakly convex, anterior angles strongly convex, anterior margin shallowly emarginate medially, lateral margin and ocular canthus producing a blunt angle, margins moderately reflexed; surface weakly convex medially, shiny, moderately and densely punctate, without setae; frontoclypeal suture feebly impressed and moderately angled medially; smooth area in front of eye approximately four times as wide as long; ocular canthus moderate and triangular(1/3 of ocular diameter), weakly punctate, without setae. Frons weakly shiny and smooth, bearing only a few erect setae beside eyes. Eyes moderately small, ratio of diameter/ interocular width: 0.57. Antenna yellowish brown, with ten antennomeres, club in male with four antennomeres, slightly longer than remaining antennomeres combined, first joint of club about as long as club. Mentum anteriorly weakly elevated and weakly convex in middle.

Pronotum strongly transverse, widest just before base, lateral margins in basal quarter strongly convex, in anterior portion moderately convex and evenly convergent anteriorly, anterior angles distinctly produced, posterior angles convex. Anterior margin medially almost straight, with a fine, complete marginal line. Surface densely and finely punctate, without minute setae in punctures; lateral and anterior lateral margins sparsely setose. Hypomeron not carinate. Scutellum triangular, with fine and dense punctures.

Elytra oblong, widest at middle, striae moderately impressed, finely and densely punctate, intervals moderately convex, with fine, dense punctures, without erect, short setae, punctures without minute setae; epipleural edge robust, ending at convex external apical angle of elytra, epipleura sparsely setose, apical border membraneous, with a rim of short microtrichomes.

Ventral surface dull, yellowish brown, with large, 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 as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/1.8. Pygidium weakly convex and dull, coarsely densely punctate, without smooth midline, punctures with fine setae along apical margin.

Legs 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 moderately widened in apical half ( Fig. 4F ); dorsal posterior margin smooth, with moderate short setae basally. Metatibia short, widest at middle; ratio width/ length: 1/ 2.9; dorsal margin weakly longitudinally convex, with two groups of spines, basal one at 1/3 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, very dense setae ventrally, dorsally smooth; metatarsomeres with a strong serrated ridge, glabrous; first metatarsomere as long as following two tarsomeres combined, slightly longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus. Fig. 4A–D . Habitus: Fig. 4E .

Diagnosis. Tetraserica yucheni Liu, Li & Ahrens , new species differs from T. bolavensensis Fabrizi, Dalstein & Ahrens, 2019 by the short ventral lobe of right paramere which is only as long as the slightly longer dorsal one and about one third of the length of the right paramere (in T. bolavensensis the ventral lobe is almost half as long as the left paramere).

Variation. Length: 8.7–10.1 mm, length of elytra: 6.8–7.9 mm, width: 5.2–6.0 mm. Female: Antennal club with three antennomeres, as long as remaining antennomeres combined. Eyes slightly smaller than in male. Pygidium flat.

Etymology. The new species is named after of its collectors, Zhao Yuchen (noun in genitive singular case).

Figures

FIGURE 4. A–F: Tetraserica yucheni Liu, Li & Ahrens, new species (holotype); G–L: T. fabriziae Liu, Li & Ahrens, new species (holotype). A, G: aedeagus, left side lateral view; B, C, H, I: parameres, dorsal view; D, J: aedeagus, right side lateral view; E, K: habitus; F, L: hind leg. Scale: 0.5 mm. Legs and habitus not to scale.