Pachyserica yaonani Ahrens, Zhao, Pham & Liu, 2024

Ahrens, Dirk, Zhao, Ming-Zhi, Pham, Phu Van & Liu, Wan-Gang, 2024, Taxonomic updates on Pachyserica Brenske, 1898 and Serica MacLeay, 1819 reveal 38 new species and new challenges of Sericini systematics regarding DNA barcodes and genus-level diagnostic key characters (Coleoptera: Scarabaeidae: Sericinae), Zootaxa 5491 (1), pp. 1-89 : 37-38

Pachyserica yaonani Ahrens, Zhao, Pham & Liu , new species

Fig. 15A–E

Type material examined. Holotype ♂ “ CHINA: TIBET, Nyingchi City, Beibeng Township , Gelin Vill., 1753 m, 29.214870°N, 95.169272°E, 18–30.VII.2023 (at light), Yao-Nan Zhang leg.” ( SCAU) . Paratype: 1 ♂ “ CHINA: TIBET, Nyingchi City, Beibeng Township , Gelin Vill., 1753 m, 29.214870°N, 95.169272°E, 18–30.VII.2023 (at light), Yao-Nan Zhang leg. / Se-XZ-8” ( CZMZ) .

Description of holotype. Length: 10.5 mm, length of elytra: 7.5 mm, width: 6.1 mm. Body oval and strongly convex, dark brown, dorsal face with strong greenish or partly weak iridescent shine, elytra slightly lighter, with dark spots, antenna yellow, dorsal surface with fine, partly patchily distributed, or dense, short, adpressed, lanceolate or oblong setae, on head, pronotum and anterior elytra with fine, erect, long setae, all setae yellow; ventral surface strongly iridescent.

Labroclypeus rectangular, wider than long, widest at base, lateral margins in basal half straight and subparallel, anteriorly convex and convergent anteriorly, anterior angles strongly convex; anterior margin straight; margins weakly reflexed; surface flat, shiny, finely and sparsely punctate, with a few long, erect setae; frontoclypeal suture indistinct, not elevated, and weakly curved; smooth area anterior to eye as wide as long; ocular canthus long and narrow (1/3 of ocular diameter), impunctate and with a long terminal seta. Frons flat, with fine and dense punctures, with a few yellow, long, erect setae and beside eyes with fine, partly dense, white, adpressed scales. Eyes small, ratio diameter/interocular width: 0.57. Antenna with ten antennomeres; club with three antennomeres, as long as remaining antennomeres combined and straight. Mentum elevated and anteriorly flattened. Labrum moderately produced medially, distinctly emarginate medially, with two large, sharp teeth beside emargination.

Pronotum wide and trapezoidal, distinctly wider than long, widest at base, lateral margins slightly concave in basal half, strongly convergent anteriorly, at middle slightly convexly bent, in anterior half weakly convex and strongly convergent anteriorly; anterior angles not produced, blunt, almost obsolete; posterior angles acute; anterior margin straight, without anterior marginal line; surface densely and finely punctate, surface with dense, fine, white, short, adpressed scale-like setae and with long, yellow, erect setae; anterior and lateral margins with long dense setae; hypomeron distinctly carinate, carina strongly produced ventrally. Scutellum slender and long, triangular, finely and densely punctate, with short, adpressed scale-like setae as in pronotum, median base widely impunctate and glabrous.

Elytra oval, widest at middle, striae distinctly impressed, finely and densely punctate, intervals weakly convex, with fine, irregularly dense punctures, dark spots completely smooth and glabrous; intervals with dense, fine, short, white, adpressed setae, intervals beside striae additionally with fine, long, erect setae; epipleural edge robust, ending at moderately curved external apical angle of elytra, epipleura densely setose; apical border narrowly membranous, with a very fine membranous rim of fine microtrichomes (magnification 100x).

Ventral surface dull, finely and densely punctate, metasternum and metacoxa finely densely setose, metacoxa additionally laterally with few robust setae; abdominal sternites finely and densely punctate, with a transverse row of coarse punctures, each bearing a short, robust seta, otherwise also finely densely setose. Mesosternum between mesocoxae almost as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.6. Pygidium weakly convex and dull, finely and densely punctate, with basally wide, smooth midline, which is grooved medially; with fine, white, dense, short, adpressed, scale-like setae and fine, sparse, long, erect setae.

Legs slender; femora with two longitudinal rows of setae, finely and somewhat irregularly punctate between rows, metafemur with numerous adpressed scales; metafemur iridescent shiny, anterior margin acute, without a continuously serrated line behind anterior margin; ventral posterior margin serrated in apical half and not widened, dorsal posterior margin completely serrated, in basal half with a few long setae which are half as long as width of metafemur. Metatibia slender and long, widest shortly before apex, ratio of width/length: 1/4.3; dorsal margin sharply carinate, with two groups of spines, basal group at middle, apical group at three quarters of metatibial length, basally with a few single, robust setae; lateral face longitudinally concave, along middle finely and moderately densely punctate, without longitudinal wrinkles, with sparse, short, white, adpressed setae; ventral margin serrated, with four equidistant, robust setae; medial face sparsely punctate and glabrous; apex interiorly near tarsal articulation concavely truncate. Tarsomeres ventrally with sparse, minute setae, dorsally impunctate; metatarsomeres laterally weakly carinate, smooth, with a strongly serrated ridge ventrally; first metatarsomere as long as following two tarsomeres combined and little longer than dorsal tibial spur. Protibia short, bidentate, external margin smooth; anterior claws symmetrical, basal tooth widened.

Aedeagus: Fig. 15A–C . Habitus: Fig. 15D–E . Female unknown.

Diagnosis. Pachyserica yaonani new species differs from the very similar and sympatric P. motuo by the shorter parameres and the phallobase of which the strong, blunt tooth on the right side of apex is absent. Externally, the male of P. yaonani can be distinguished by the slightly shorter antennal clubs and last abdominal sternite which is not strongly bent ventrally.

Etymology. This species (noun in genitive case singular) is named after the collector, Mr. Yao-Nan Zhang (Beijing, China).

Genbank accession numbers: Paratype (voucher: Se-XZ-8; Cox 1: PP977010).

Variation. Length: 10.1–10.5 mm, length of elytra: 7.1–7.5 mm, width: no variation measurable.

Figures

FIGURE 15. A–E: Pachyerica yaonani new species (holotype); F–J: P. sunfengyii new species (holotype); A, H: aedeagus, left side lateral view; C, J: aedeagus, right side lateral view; B, I: parameres, dorsal view; D, F: habitus, dorsal view; E, G: habitus, lateral view. Scale bar: 0.5 mm. Habitus images not to scale.