Pachyserica chenchangchini 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 : 45-46

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

Fig. 18F–K

Type material examined. Holotype ♂ “[ China] Yunnan, Te-hung-chou, Jui-li, Jui-li Botanical garden 1200m 2015, IX-10 Y.-T. Chung Leg. CCCC / ex coll. Chang-Chin Chen ” ( SCAU).

Description of holotype. Length: 8.0 mm, length of elytra: 5.7 mm, width: 4.6 mm. Body oval and strongly convex, reddish brown including legs, frons with dark green toment, pronotum with green shine, elytra with large, dark spots, antennae yellow, dorsal surface weakly iridescent, with fine, partly patchily distributed, or dense, short, adpressed, white setae, on head, pronotum and anterior elytra with long, fine, erect, yellow setae.

Labroclypeus rectangular, distinctly 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, moderately shiny, coarsely and densely punctate, with numerous 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 without short terminal seta. Frons flat, with fine and dense punctures and fine, dense, white, short, adpressed setae as well as with yellow, long, erect setae. Eyes small, ratio diameter/interocular width: 0.57. Antenna with ten antennomeres; club with three antennomeres, 1.4 times as long as remaining antennomeres combined and straight. Mentum elevated and anteriorly flattened. Labrum moderately produced medially, distinctly but shallowly emarginate medially.

Pronotum trapezoidal, distinctly wider than long, widest at base; lateral margins in basal half slightly concave, strongly convergent anteriorly, at middle slightly convexly bent, in anterior half weakly convex and strongly convergent anteriorly; anterior angles weakly produced, broadly rounded; posterior angles almost right-angled, rounded at tip; anterior margin straight, with a fine anterior marginal line; surface densely and finely punctate, on a narrow midline and a few small green areas on each side impunctate, with dense, fine, white, short, adpressed setae and with long, yellow, erect setae; anterior and lateral margins with sparse, long, erect setae; hypomeron distinctly carinate, carina strongly produced ventrally. Scutellum long, triangular, finely and even more densely punctate than pronotum, each puncture bearing a short, adpressed scale-like seta, basomedial and apical areas widely impunctate and glabrous.

Elytra oval, widest at middle, striae distinctly impressed, finely and densely punctate, intervals weakly convex, with fine, irregularly dense punctures, green spots completely smooth and glabrous; intervals with dense, short, adpressed lanceolate setae which usually aggregate to white spots, additionally with some 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, finely and moderately densely setose, metasternum laterally including metepisternum and metacoxa with dense, short, and adpressed lanceolate setae, metacoxa additionally with few robust setae laterally; abdominal sternites finely and densely punctate, covering dense, adpressed lanceolate setae, with a transverse row of coarse punctures, each bearing a short, robust seta. Mesosternum between mesocoxae almost 1.5 times as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.6. Pygidium strongly convex and dull, finely and densely punctate, smooth midline basally wide, with fine, white, dense, short, adpressed setae and fine, long, erect setae.

Legs slender; femora with two longitudinal rows of setae, coarsely and densely punctate between rows; metafemur dull, 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 shortly before middle, apical group at two thirds of metatibial length, basally with a few single, robust setae; lateral face longitudinally concave, with longitudinal wrinkles, finely and sparsely punctate, with dense, fine, short, adpressed setae; ventral margin serrated, with three equidistant, robust setae; medial face impunctate and glabrous; apex interiorly near tarsal articulation concavely truncate. Tarsomeres ventrally with sparse, minute setae, dorsally impunctate; metatarsomeres laterally weakly carinate, with a strongly serrated ridge ventrally; first metatarsomere as long as following two tarsomeres combined and twice as long as dorsal tibial spur. Protibia short, bidentate, external margin smooth; anterior claws symmetrical, basal tooth of inner claw normal.

Aedeagus: Fig. 18I–K . Habitus: Fig. 18G, H . Female unknown.

Diagnosis. Pachyserica chenchangchini new species is in shape of aedeagus similar to P. putaoensis Ahrens, 2006 . The new species differs from the latter by the narrower and longer left paramere, of which the basal lobe is distinctly longer and narrower; the right paramere also has a basal lobe which is absent in P. putaoensis ; finally, the phallobase is longer and narrower than that of P. putaoensis .

Etymology. The new species (noun in genitive case singular) is named after Mr. Chang-Chin Chen (Taoyuan, Taiwan) who kindly provided the holotype specimen.

Figures

FIGURE 18. A–F: Pachyserica dieuthuyae new species (holotype); G–K: P. chenchangchini new species (holotype); A, I: aedeagus, left side lateral view; D, K: aedeagus, right side lateral view; C, J: parameres, dorsal view; B: aedeagus, dorsal view; E, G: habitus, dorsal view; F, H: habitus, lateral view. Scale bar: 0.5 mm. Habitus images not to scale.