Pachyserica tayyentu 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 : 35-36

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

Fig. 14A–F

Type material examined. Holotype ♂ “ Coll. I.R.Sc.N.B. Vietnam, Tay Yen Tu Nat. Res. 21°11′10″N 106°43′25″E 7–11.vii.2013 day collecting Leg. J. Constant & J. Bresseel, I.G.: 32.454 / 1252 Asia Sericini spec.” ( ISNB).

Description of holotype. Length: 9.1 mm, length of elytra: 6.8 mm, width: 5.0 mm. Body oval and strongly convex, dark brown, dorsal face greenish shine, elytra with darker spots, antenna yellow, ventral surface and legs brown, dorsal surface with iridescent shine, with fine, partly patchily distributed or dense, short, adpressed, white, or yellowish setae.

Labroclypeus large, distinctly wider than long, widest at base, lateral margins in basal half straight and subparallel, anteriorly convex and convergent anteriorly, anterior angles convex, anterior margin widely and deeply emarginate medially; margins weakly reflexed; surface transversely convex anteriorly, shiny, finely and densely punctate, with a few fine and long, erect setae behind anterior margin; frontoclypeal suture distinct, slightly elevated, and weakly curved; smooth area anterior to eye 1.3 times as wide as long; ocular canthus long and narrow (1/2.5 of ocular diameter), impunctate and without short terminal seta. Frons slightly transversely impressed behind frontoclypeal suture, with fine and moderately dense punctures and almost glabrous, with a few single long, erect setae beside eyes and behind frontoclypeal suture. Eyes small, ratio diameter/interocular width: 0.55. Antenna with ten antennomeres; club with three antennomeres, as long as remaining antennomeres combined and straight. Mentum elevated and anteriorly flattened. Labrum strongly produced medially, distinctly emarginate medially, with two large, sharp teeth beside emargination.

Pronotum narrow and trapezoidal, little wider than long, widest at base, lateral margins almost straight, strongly convergent anteriorly, at middle slightly convexly bent; anterior angles not produced, obsolete; posterior angles almost acute; anterior margin straight, without anterior marginal line; surface densely and finely punctate, surface with some smaller, more densely punctate impressions, some patches and midline widely impunctate, with dense, fine, white, short, adpressed setae; anterior and lateral margins with long dense setae; hypomeron distinctly carinate, carina weakly produced ventrally. Scutellum slender and long, triangular, finely and densely punctate, with short, adpressed setae as in pronotum, median base widely impunctate and glabrous.

Elytra oval, widest at posterior third, striae distinctly impressed, finely and densely punctate, intervals flat, with fine, dense punctures, dark spots completely smooth and glabrous; intervals with single, fine and short, white, adpressed setae, additionally with a very few single longer, white, erect, scale-like 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 finely, moderately densely setose. Mesosternum between mesocoxae half as wide as the slender mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.43. Pygidium moderately convex and dull, finely and densely punctate, with basally wide, smooth midline, with fine, dense, short, semierect and long, erect setae.

Legs moderately slender; femora with two longitudinal rows of setae, coarsely and densely punctate between rows; 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 moderately long, widest shortly before apex, ratio of width/length: 1/4.3; dorsal margin sharply carinate, with two groups of spines, basal group shortly before middle, apical group at three quarters of metatibial length, basally with a few single, robust setae; lateral face, along the middle finely and very sparsely punctate, punctures on dorsal portion denser, with some superficial longitudinal wrinkles, glabrous; ventral margin serrated, with two very widely separated 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 not carinate, smooth, with a strongly serrated ridge ventrally; first metatarsomere as long as following two tarsomeres combined and little less than twice as long as dorsal tibial spur. Protibia short, bidentate, external margin smooth; anterior claws symmetrical, basal tooth of inner claw normal.

Aedeagus: Fig. 14A–D . Habitus: Fig. 14E–F . Female unknown.

Diagnosis. Pachyserica tayyentu new species differs from the very similar P. huanglianensis Ahrens, 2006 from Yunnan ( China) by the shorter and wider right paramere whose basal lobe is also larger.

Etymology. The name of this new species (noun in apposition) is derived from the name of its type locality Tay Yen Tu Nature Reserve ( Vietnam).

Figures

FIGURE 14. A–F: Pachyserica tayyentu new species (holotype); G–L: P. yinhengi new species (holotype); A, I: aedeagus, left side lateral view; D, L: aedeagus, right side lateral view; C, K: parameres, dorsal view; B, J: aedeagus, dorsal view; E, G: habitus, dorsal view; F, H: habitus, lateral view. Scale bar: 0.5 mm. Habitus images not to scale.