Pachyserica tianxuani 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 : 46-47

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

Fig. 19G–K

Type material examined. Holotype ♂ “ CHINA: Chongqing, Mt. Jinfoshan (N-Slope) 30.VI–3.VII.2022, 1500 m, Tian-Xuan Gu leg.” ( SCAU).

Description of holotype. Length: 9.7 mm, length of elytra: 7.2 mm, width: 5.4 mm. Body oblong-oval and convex, including antennae and legs entirely reddish brown, elytra with dark, green spots, dorsal surface dull, partly with weak iridescent shine, frons and pronotum with dark green toment and long, erect, yellow setae, entire body with dense, adpressed, white, scale-like setae, elytra with some longer and erect setae.

Labroclypeus subrectangular, distinctly wider than long, widest at middle, lateral margins weakly convex, in anterior half more strongly convergent; anterior angles weakly rounded; anterior margin straight; margins weakly reflexed; surface flat, shiny, coarsely and densely punctate, with dense, long and erect setae; frontoclypeal suture distinct, finely incised and flat, weakly curved; smooth area anterior to eye as wide as long; ocular canthus moderately long and narrow (1/3 of ocular diameter), with three moderately long setae in apical half. Frons flat, with large, dense punctures and adpressed scale-like setae dense, setae sparser on disc, additionally with dense, long, erect setae. Eyes small, ratio diameter/interocular width: 0.57. Antenna with ten antennomeres; antennomeres three to six almost as wide as long, antennomere seven transverse and short, club with three antennomeres, twice as long as remaining antennomeres combined and reflexed. Mentum strongly elevated. Labrum strongly produced and distinctly emarginate medially, with two large, sharp teeth beside emargination.

Pronotum trapezoidal, distinctly wider than long, widest at base, lateral margins slightly concave in basal half and strongly convergent anteriorly, in anterior half slightly convex and strongly convergent anteriorly; anterior angles not produced, broadly rounded in tip; posterior angles almost right-angled; anterior margin straight, with distinct and complete anterior marginal line; surface somewhat uneven, densely and finely punctate, midline and its two oblique lateral extensions on each side impunctate, each puncture bearing a short, adpressed scale-like seta, setae laterally denser and thicker; anterior and lateral margins with sparse, long and erect setae; hypomeron distinctly carinate, carina weakly produced ventrally. Scutellum wide and long, triangular, finely and very densely punctate, with minute, adpressed scale-like setae, basomedial and lateroapical areas narrowly impunctate and glabrous.

Elytra oval, widest at posterior quarter, 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, and with fine, single, white, longer, scale-like setae; epipleural edge fine, 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, coarsely and densely punctate, hypomeron and mesosternum with dense, long and erect setae, metasternum and metacoxa with short, dense, adpressed scale-like setae, metasternal disc additionally with fine, long setae; metacoxa additionally laterally with few robust setae; abdominal sternites finely and moderately densely punctate, with a transverse, somewhat irregular row of large punctures, each bearing a short, robust seta, otherwise also covered with fine, adpressed, scale-like setae. Mesosternum between mesocoxae almost as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.36. Pygidium strongly convex, moderately shiny, with a wide, impunctate midline, otherwise coarsely and densely punctate, with dense, short, adpressed scale-like setae in basal half and with moderately dense, erect long setae in apical half.

Legs slender; femora with two longitudinal rows of setae, finely and densely punctate; metafemur iridescent shiny, anterior margin acute, without a continuously serrated line behind anterior margin; ventral posterior margin serrated in apical half and weakly 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 at 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 longitudinally concave, finely and densely punctate, with longitudinal wrinkles, with some minute, adpressed setae; ventral margin serrated, with three, almost equidistant, robust setae; medial face sparsely punctate and glabrous; apex interiorly near tarsal articulation concavely truncate, finely serrated. Tarsomeres ventrally with moderately dense, minute setae, protarsomeres dorsally smooth, meso- and metatarsomeres dorsally with superficial and longitudinal wrinkles, and a few minute setae; meso- and metatarsomeres with a strongly serrated ridge ventrally; metatarsomeres laterally carinate, glabrous ventrally; first metatarsomere slightly shorter than following two tarsomeres combined and distinctly longer than dorsal tibial spur. Protibia short, bidentate, external margin smooth; anterior claws symmetrical, basal tooth of inner claw normal.

Aedeagus: Fig. 19I–K . Habitus: Fig. 19G, H . Female unknown.

Diagnosis. Pachyserica tianxuani new species can be distinguished from the most similar P. squamifera (Frey, 1972) ( Fig. 19A–D ) by the distinctly longer parameres. Pachyserica tianxuani sp. nov differs from the also similar P. wangzizhaoi new species by the left paramere being straight and oblique apical margin placed externally.

Etymology. This species (noun in genitive case singular) is named after the collector of the holotype, Mr. Tian-Xuan Gu (Leshan, China).

Figures

FIGURE 19. A–F: Pachyserica squamifera (Frey, 1972) (holotype); G–K: P. tianxuani new species (holotype); A, I: aedeagus, left side lateral view; D, K: aedeagus, right side lateral view; B, J: parameres, dorsal view; C: aedeagus, dorsal view; E, G: habitus, dorsal view; F, H: habitus, lateral view. Scale bar: 0.5 mm. Habitus images not to scale.