Trioserica shiyiduiensis 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 : 349-350

Trioserica shiyiduiensis Ahrens, Liu & Fabrizi , new species

Figure 2A–D

Type material examined. Holotype, ♂: “ Yunnan, Jinghong City, Jinghong Farm, No.1 Parvial Field, Team 11 [ Shiyidui in Chinese ], 2009.III.16 759m, leg. Meng LZ / LW-632” ( IZAS) . Paratype: 1 ♀ “ Yunnan, Jinghong City, Jinghong Farm, No.1 Parvial Field, Team 11 [ Shiyidui in Chinese ], 2009.III.16 759m, leg. Meng LZ / LW-1153” ( IZAS) .

Description of the holotype, male. Length: 6.1 mm, length of elytra: 4.6 mm, width: 3.5 mm. Body oblong, yellowish brown, dorsal surface with small or larger dark spots, frons dark brown with greenish shine, antenna yellow, dorsal surface 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 weakly convex 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: 0.67. Antenna yellow, composed of 10 antennomeres; club with four lamellae, little longer than remaining antennomeres combined. Mentum convexly elevated anteriorly.

Pronotum moderately wide, widest at base, lateral margins nearly straight and strongly convergent anteriorly, in anterior third convex and 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 normally punctate, punctures with microscopic setae; anterior and lateral margins sparsely setose. 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, flat; 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/ 1.94. 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 lacking in holotype.

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 bluntly widened at middle, forming a blunt tooth, 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/ 3.0; dorsal margin completely sharply carinate, with two groups of spines; basal group of spines shortly before half 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; pro- and mesotarsomeres ventrally with dense and short setae. Metatarsomeres ventrally glabrous, with a strongly serrated, longitudinal carina; metatarsomere 1 distinctly longer than following tarsomere, and little longer than dorsal tibial spur. Protibia moderately long, tridentate; protarsal claws symmetric.

Aedeagus: Fig. 2A–C . Habitus: Fig. 2D .

Variation. Length: 6.1–7.1 mm, length of elytra: 4.6–5.3 mm, width: 3.5–4.5 mm. Female: antennal club short, little shorter than remaining antennomeres combined, composed of three antennomeres; eyes as large as in male; posterior margin of metafemur weakly convex.

Diagnosis. Trioserica shiyiduiensis new species differs from all other Chinese Trioserica species by the bluntly widened posterior margin of metafemur in male, and, of course by the shape of aedeagus: the right paramere is long and straight, the left paramere is straight in dorsal view.

Etymology. The new species is named after its type locality, Shiyidui.

Figures

FIGURE 2. A–D: Trioserica shiyiduiensis Ahrens, Liu & Fabrizi, new species (holotype); E–H: T. cangyuanensis Ahrens, Liu & Fabrizi, new species (holotype); I–L: T. daweishana Ahrens, Liu & Fabrizi, new species (holotype). A, E, I: aedeagus, left side lateral view; C, G, K: aedeagus, right side lateral view; B, F, J: parameres, dorsal view; D, H, L: habitus. Scale: 0.5 mm. Habitus not to scale.