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) Author Ahrens, Dirk 0000-0003-3524-7153 Zoologisches Forschungsmuseum A. Koenig, Adenauerallee 127, 53113 Bonn, Germany ahrens. dirk _ col @ gmx. de; https: // orcid. org / 0000 - 0003 - 3524 - 7153 ahrens.dirk_col@gmx.de Author Zhao, Ming-Zhi 0000-0002-3158-6177 College of Plant Protection, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, P. R. China zhaomzhai @ 126. com; https: // orcid. org / 0000 - 0002 - 3158 - 6177 zhaomzhai@126.com Author Pham, Phu Van 0000-0001-9369-6649 Institute of Ecology and Biological resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam phupham. iebr @ gmail. com; https: // orcid. org / 0000 - 0001 - 9369 - 6649 phupham.iebr@gmail.com Author Liu, Wan-Gang 0000-0003-3524-7153 Zoologisches Forschungsmuseum A. Koenig, Adenauerallee 127, 53113 Bonn, Germany ahrens. dirk _ col @ gmx. de; https: // orcid. org / 0000 - 0003 - 3524 - 7153 & SKLLQG, Institute of Earth and Environment, Chinese Academy of Sciences, Yanxiang Road 97, Yanta District, Xi’an 710061 P. R. China liuwangang @ ieecas. cn; https: // orcid. org / 0000 - 0003 - 4788 - 7967 & Zoologisches Forschungsmuseum A. Koenig, Adenauerallee 127, 53113 Bonn, Germany ahrens. dirk _ col @ gmx. de; https: // orcid. org / 0000 - 0003 - 3524 - 7153 ahrens.dirk_col@gmx.de text Zootaxa 2024 2024-08-01 5491 1 1 89 http://dx.doi.org/10.11646/zootaxa.5491.1.1 journal article 301609 10.11646/zootaxa.5491.1.1 34c72ca9-f976-4c79-a123-f93af60fa26c 1175-5334 13211849 0612E62C-A53D-42BE-8578-68EC77D34627 Serica (s. l.) taythien Ahrens, Zhao, Pham & Liu , new species Fig. 11F–J Type material examined. Holotype ♂ “VS819 Vietnam Vinh Phuc Pro., Tay Thien 14.v.2004 IEBR Collection Serica spnX2 / Asia Sericini 1358 spec.” ( IEBR ) . Paratypes : 1 ♂ “VS425 Vietnam Vinh Phuc Pro., Tam Dao Dist. , Tay Thien 16.v.2004 IEBR Collection Serica nigrogitatta _gr_spVi1” ( IEBR ) , 1 ♂ “VS832 Vietnam Vinh Phuc Pro., Tay Thien 16.v.2004 IEBR Collection Serica spnX2” ( IEBR ) , 1 ♂ “VS0914 Vietnam Ha Giang Pro., Quan Ba Heaven Gate , 19.vi.2023 23°02′57′′N , 104°59′33′′E N.T. Pham et al. Serica spVi1” ( IEBR ) . Description of holotype . Length: 9.9 mm , length of elytra: 7.1 mm , width: 5.9 mm . Body oval and strongly convex, dark brown, head, pronotum and some spots on elytra with greenish shine, elytra with darker spots, antenna yellow, dorsal surface weakly shiny or iridescent, with moderately dense, short, narrow, curved, white setae. Labroclypeus slightly wider than long, widest at base; lateral margins in basal half straight and subparallel, anteriorly strongly convex and convergent, anterior angles strongly convex, anterior margin deeply emarginate medially; margins weakly reflexed; surface flat, shiny, basally narrowly dull, finely and densely punctate, with a dense and long, erect setae and a few white fine scales at base; frontoclypeal suture distinct, slightly elevated, and weakly curved; smooth area anterior to eye as wide as long; ocular canthus long and narrow (1/4 of ocular diameter), with a few fine punctures, minute setae, and a short terminal seta. Frons flat; surface with fine and dense punctures and with white, short, adpressed scales, additionally with numerous long, erect setae. Eyes small, ratio diameter/interocular width: 0.6. Antenna with ten antennomeres; club with three antennomeres, 1.1 times as long as remaining antennomeres combined and straight. Mentum elevated and anteriorly flattened. Labrum elliptical, well produced and distinctly emarginate medially. Pronotum trapezoidal, little wider than long, widest at base, lateral margins in basal half straight and strongly convergent anteriorly, in anterior half weakly convex and convergent anteriorly; anterior angles weakly produced and acute, posterior angles acute; anterior margin almost straight, with fine and indistinct but medially complete anterior marginal line; surface densely and finely punctate, basal midline narrowly impunctate, with dense, white, short, adpressed scales; anterior and lateral margins with long sparse setae; hypomeron distinctly carinate, carina slightly produced ventrally. Scutellum slender and long, dull, triangular, finely and densely punctate, with white scales as in pronotum, base widely impunctate and glabrous. Elytra oval, widest at middle, striae weakly impressed, finely and densely punctate, intervals weakly convex, with fine, dense punctures, dark spots completely smooth; intervals with moderately dense, short and narrow, curved, white scales, each interval additionally with a few, single, longer, white scales; epipleural edge fine, ending at moderately curved external apical angle of elytra, epipleura densely setose, apical border membranous, with a fine membranous rim of fine microtrichomes (magnification 100x). Ventral surface dull, finely and densely punctate, including metacoxa densely setose, metacoxa laterally with a more robust and longer setae and along the anterior margin with a few small white scales; abdominal sternites finely and densely punctate, with a transverse row of coarse punctures, each bearing a short, robust seta, otherwise finely densely setose. Mesosternum between mesocoxae half as wide as the slender mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.51. Pygidium moderately convex and dull, finely and densely punctate, with wide, smooth midline, with fine, sparse, short, white scales, and numerous fine long setae along apical margin. Legs moderately slender; femora with two longitudinal rows of setae, coarsely and densely punctate between rows; metafemur 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 moderately wide and moderately long, widest a quarter before apex, ratio of width/length: 1/3.5; 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, coarsely densely punctate, punctures somewhat elongate, with minute setae; ventral margin serrated, with three robust setae of which the two distal ones are more widely separated; medial face sparsely punctate and glabrous; apex interiorly near tarsal articulation indistinctly bluntly truncate. Tarsomeres ventrally with sparse, minute setae, dorsally finely punctate; metatarsomeres laterally carinate, with some wrinkles beside punctures, 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 asymmetrical, basal tooth of inner claw short and lobiform, basal tooth of inner claw normal. Aedeagus: Fig. 11G–J . Habitus: Fig. 11F . Female unknown. Diagnosis. Serica taythien new species is quite similar to S. tryznai and S. parasquamosa , however, it differs in the longer, weakly curved left paramere which is almost subequal in length to the right; Serica taythien differs from S. nigrogutta and many other species of the S. nigroguttata group by the large median sclerotized plate in the dorsal mesoapical emargination of phallobase. Etymology. The name of this species is derived from its type locality Tay Thien (noun in apposition). Variation. Length: 8.8–9.9 mm , length of elytra: 6.5–7.1 mm , width: 5.7–5.9 mm .