Trioserica dinghushanica Ahrens, Liu & Fabrizi, 2021

Ahrens, Dirk, Liu, Wangang, Fabrizi, Silvia & Bai, Ming, 2021, Taxonomic review on the Trioserica Moser, 1922 species of China (Coleoptera Scarabaeidae: Melolonthinae: Sericini), Zootaxa 4999 (4), pp. 343-355 : 346

Trioserica dinghushanica Ahrens, Liu & Fabrizi , new species

Figure 1E–I

Type material examined. Holotype, ♂: “ Guangdong, 13.VII.1965 / =LW614a” ( IZAS) . Paratypes: 1 ♂ “Mts. Din- ghushan, Guangdong, 17–22.VI.1979, leg. Xie Yingshu, Xia Shiyang” ( IZAS) , 1 ♂ “ Mt. Dinghushan , Guangdong, 7.VII.1964, leg. Zhang Liansheng, No. En-048214” ( LSSYU) .

Description of the holotype, male. Length: 6.5 mm, length of elytra: 4.8 mm, width: 3.9 mm. Body oblong, yellowish brown, dorsal surface with small dark spots, frons dark brown, antenna yellow, dorsal surface moderately dull and almost glabrous.

Labroclypeus subtrapezoidal and wide, widest at base, lateral margins convex and convergent to strongly rounded anterior angles; margins weakly reflexed, anterior margin narrowly emarginate medially; lateral margin and ocular canthus producing a blunt angle; surface distinctly convex medially and shiny, finely and densely punctate, distance between punctures less than their diameter, with a few short, erect setae. Frontoclypeal suture feebly incised and medially curved; smooth area in front of eye short and approximately three times as wide as long. Ocular canthus short and triangular, laterally sparsely punctate, with a single, short terminal seta. Frons dull, with fine and evenly dense punctures, with a few short setae beside eyes. Eyes small, ratio of diameter/ interocular width: 0.64. Antenna yellow, composed of 10 antennomeres; club with four lamellae, as long as remaining antennomeres combined. Mentum convexly elevated anteriorly.

Pronotum moderately wide, widest at base, lateral margins weakly but evenly convex and weakly convergent anteriorly; anterior angles distinctly produced and sharp; posterior angles blunt; anterior margin convexly produced medially, with a distinct and complete marginal line; basal margin without marginal line; surface with even, dense and fine punctures, posterior midline broadly smooth, punctures with microscopic setae; anterior and lateral margins glabrous. Hypomeron distinctly carinate. Scutellum narrow and short, with fine and dense punctures, medially smooth, punctures with microscopic setae.

Elytra oblong, widest shortly behind middle; striae distinctly impressed, finely and densely punctate; intervals densely finely punctate, even ones flat, odd intervals weakly convex, punctures concentrated along striae; epipleural margin robust, ending at strongly curved external apical angle of elytra; epipleura sparsely setose; apical border narrowly membraneous, with a very fine rim of short microtrichomes.

Ventral surface dull, with large and dense punctures, sparsely and shortly setose, setae partly adpressed. Mesosternum between mesocoxae as wide as mesofemur, with irregularly scattered robust and long setae. Ratio of length of metepisternum/ metacoxa: 1/ 1.83. Metacoxa glabrous, laterally with numerous robust setae. Each abdominal sternite with indistinct transversal row of coarse punctures bearing each a robust seta between fine and dense punctation. Pygidium evenly weakly convex, finely and densely punctate, with a narrow smooth midline, glabrous, with a few longer setae beside apical margin.

Legs narrow and moderately long, with shiny surface; femur with two longitudinal rows of setae, finely and moderately densely punctate. Metafemur ventrally dull, sharply carinate anteriorly, without a submarginal serrated line; posterior margin straight, ventral posterior margin in distal half only weakly widened and smooth; dorsal margin smooth, with short setae. Metatibia short and wide, widest at middle; ratio width/ length: 1/ 2.9; dorsal margin completely sharply carinate, with two groups of spines; basal group of spines at one third of metatibial length, apical one at three quarters of metatibial length; lateral face longitudinally convex, with a few fine and very sparse punctures; ventral margin finely serrated, with four robust, equidistant spines; medial face impunctate, apex interiorly near tarsal articulation sharply truncate. Tarsomeres dorsally glabrous and sparsely finely punctate; protarsomeres ventrally with dense and short setae (mesotarsomeres lacking in holotype). Metatarsomeres ventrally glabrous, with a strongly serrated, longitudinal carina; metatarsomere 1 distinctly longer than following tarsomere, dorsal metatibial spur lacking in holotype. Protibia moderately long, tridentate; protarsal claws symmetric.

Aedeagus: Fig. 1E–H . Habitus: Fig. 1I .

Female unknown.

Variation. Length: 6.5–7.4 mm, length of elytra: 4.8–5.5 mm, width: 3.9–4.9 mm.

Diagnosis. Trioserica dinghushanica new species differs from Tr. maculipennis by the shorter left paramere being inserted more dorsally, and by the much narrower right paramere, whose insertion to phallobase is not produced as distal as in Tr. maculipennis .

Etymology. The new species is named after its occurrence in the Dinghushan mountains.

Figures

FIGURE 1. A–D: Trioserica maculipennis (Miyake & Yamaya, 2001) (holotype); E–H: T. dinghushanica Ahrens, Liu & Fabrizi, new species (holotype); I–L: T. lilongensis Ahrens, Liu & Fabrizi, new species (holotype). A, E, J: aedeagus, left side lateral view; C, H, L: aedeagus, right side lateral view; B, F, G, K: parameres, dorsal view; D, I, M: habitus. Scale: 0.5 mm. Habitus not to scale.