Pachyserica yinhengi 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 : 36-37

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

Fig. 14G–L

Type material examined. Holotype ♂ [ China] “ Beibeng, Motuo , Xizang, 25.Ⅴ. 1983, 850m, leg. Han Yinheng / LW-260” ( IZAS) . Paratype: 1 ♂ [ China] “ Beibeng, Motuo , Xizang, 24.VI. 1983, 850m, leg. Han Yinheng ” ( ZFMK) .

Additional material examined. 1 ♀ “ CHINA: TIBET, Nyingchi City, Motuo , 96k, 1100 m, 2023.VII.17, at light Hao-Yi Liu leg. / Se-XZ-3” ( CZMZ) , 1 ♀ “ CHINA: TIBET, Nyingchi City, Motuo , 96k, 1100 m, 2023.VII.17, at light Hao-Yi Liu leg. / Se-XZ-4” ( CZMZ) , 1 ♀ “ CHINA: TIBET, Nyingchi City, Beibung , 864 m, 29.24807910°N, 95.18061479°E 2023.VII.12, Hao-Yi Liu leg. / Se-XZ-5” ( CZMZ) , 1 ♀ “ CHINA: TIBET, Nyingchi City, Beibung , 864 m, 29.24807910°N, 95.18061479°E 2023.VII.12, Hao-Yi Liu leg.” ( CZMZ) .

Description of holotype. Length: 10.0 mm, length of elytra: 7.5 mm, width: 6.4 mm. Body oval and strongly convex, dark brown, dorsal face with greenish shine, elytra slightly lighter, with dark spots, antenna yellow, dorsal surface with weak iridescent shine, with fine, partly patchily distributed, or dense, short, adpressed, white, or yellowish setae, on head, pronotum and anterior elytra with long fine erect, yellow setae.

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 numerous long, erect; 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, with a 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, 1.3 times 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 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, and 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 setae and with long, yellow, erect 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 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, on sutural interval and on base additionally with a few 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: 1/1.54. Pygidium strongly convex and dull, finely and densely punctate, with basally wide, smooth midline, 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 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: 1/4.0; 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 sparsely punctate, without longitudinal wrinkles, with sparse, short, white, adpressed setae; ventral margin serrated, with three 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 not carinate, smooth, 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. 14I–L . Habitus: Fig. 14G–H . Female unknown.

Diagnosis. Pachyserica yinhengi new species differs from all other Himalayan Pachyserica species by the long, narrow, and equally long parameres.

Etymology. The new species (noun in genitive case singular) is named after its collector, Han Yinheng.

Genbank accession numbers: Female specimens, not included in type series (voucher: Se-XZ-3; Cox 1: PP977015/ Se-XZ-4; Cox1: PP977014/ Se-XZ-5; Cox1: PP977013).

Remark. The here cited female specimens cannot be assigned with absolute certainty to this species, due to its similar siblings in the same area in Tibet. However, these female specimens differ in terms of COI data from the two following species, and Pachyserica yinhengi new species is the only closely, highly similar relative in the area. However, species can be robustly morphologically distinguished only based on male genitalia, not by external morphology.

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.