﻿An update to the taxonomy of Serica MacLeay, 1819 (sensu lato) from China (Coleoptera, Scarabaeidae, Sericinae, Sericini)

﻿Abstract In this paper we update the knowledge on the species of Serica McLeay, 1819 (sensu lato) occurring in Yunnan, Sichuan, and Shaanxi provinces, China. Three new species are described: Sericaallonanhua Liu, Ahrens, Li & Su, sp. nov., S.breviantennalis Liu, Ahrens, Li & Su, sp. nov., and S.fengensis Liu, Ahrens, Li & Su, sp. nov. The key to the species groups and species is updated. The habitus and male genitalia of the new species are illustrated, and a map showing their distribution is provided. New distributional data are given for four species.


Introduction
The tribe Sericini Kirby, 1837 includes more than 200 genera and 4000 species.While the phylogenetic position of Sericini appears now to be resolved, its internal relationships still await refinement with additional sampling of taxa and genetic markers needed (Dietz et al. 2023).
The genus Serica was established by Macleay (1819), and the type species, by monotypy, is Serica brunnea (Linnaeus, 1758) (Ahrens 1999(Ahrens , 2005a)).It is one of the most diverse sericine genera in the Palaearctic Region, with hundreds of species in the temperate regions of Eurasia and higher mountains of Asia (Ahrens 2005a(Ahrens , 2006b(Ahrens , 2007b;;Ahrens and Bezděk 2016).Under currently understood, Serica is polyphyletic, as shown by a series of molecular phylogenetic studies (Ahrens and Vogler 2008;Liu et al. 2015b;Eberle et al. 2017).ZooKeys 1185ZooKeys : 181-198 (2023)), DOI: 10.3897/zookeys.1185.109154 Xie Su et al.: Update to the taxonomy of Serica from China Ahrens (1999Ahrens ( , 2005a) ) established the subgenus Serica (sensu stricto) for the species most closely related to the type species, S. brunnea (Linnaeus, 1758).Molecular evidence suggests that many species with an elongate body shape, trilamellate antennal club, and narrower, longer legs have been placed incorrectly in Serica by many authors due to convergence of these characters (Ahrens 1999(Ahrens , 2005a)).As a consequence of the often occurring strong homoplasy, many diagnostic characteristics of Sericini have been proven to be misleading for higher classification, including the number of antennomeres which traditionally has been prominently used for the definition of genera of Sericini (Ahrens and Vogler 2008).This had led to many unresolved problems in generic classification, especially in the "Maladera-Neoserica-Serica" clade (Eberle et al. 2017).Therefore, many of our recent taxonomic treatments of Serica, Maladera Mulsant & Rey, 1871, and Neoserica Brenske, 1894 divided these genera into compact species groups or subgenera, which are likely to represent monophyletic groups, as a basis for future systematic work (e.g.Ahrens and Fabrizi 2016;Fabrizi et al. 2021).These are generally summarized under "sensu lato" in association with the respective genus name, or as subgenera.The subgenus Serica (sensu stricto) has had a vast radiation in the Asian highlands, mainly the Himalayas, eastern Tibet, and the mountains of the eastern Palaearctic (Ahrens 2007c).

Materials and methods
The terminology and methods used for measurements, specimen dissection, and genital preparation follow Ahrens (2004).Data from specimens examined are cited in the text with original label contents given in quotation marks; multiple labels for a single specimen are separated by a "/".Descriptions and illustrations of new taxa are based on the holotype specimen if not otherwise stated, while the variation of specimens is given separately under "variation".Male genitalia were glued to a small, pointed card and photographed in both lateral and dorsal views using an Olympus SZ61-TR stereomicroscope with an Mshot MD 50 digital camera.All the parameter adjustment and images acquisition were done in MShot Image Analysis System v. 1.6.1.To obtain an focused image, several partly focused images were also focus-stacked with this software.The resulting images were subsequently digitally edited with Adobe Photoshop v. 21.0.2.Distribution maps were generated using ArcGIS v. 10.3, based on the geographical coordinates from the labels.Description of the holotype.Length 7.9 mm, elytral length 5.6 mm, width 4.1 mm.Body oblong, reddish brown; frons dark reddish brown, dull; legs yellowish brown; antenna yellow, with moderately long setae on head dorsal surface.
Labroclypeus wide, trapezoidal, with lateral margins moderately convex and convergent, producing a blunt angle with ocular canthus; anterior angles strongly convex; anterior margin distinctly emarginate medially; margins moderately reflexed; surface moderately convex, finely and densely punctate, with numerous long and erect setae; frontoclypeal suture distinct, moderately curved; ocular canthus moderately narrow (length slightly >1/3 ocular width), smooth and glabrous, with four terminal setae.Frons with dull toment, with fine, moderately dense punctures, anteriorly and laterally with a few long setae.Antenna with nine antennomeres, club with three antennomeres, 1.5 times as long as remaining antennomeres combined, distinctly reflexed.Eyes small, ratio diameter to interocular width 0.47.Mentum convexly elevated and flattened anteriorly.
Pronotum moderately wide, widest at base, lateral margins moderately convex and convergent anteriorly; anterior angles acute, moderately produced, posterior angles blunt; anterior margin weakly convex, marginal line fine but complete; basal margin without marginal line; surface with coarse, dense punctures and minute setae, anteriorly and laterally bearing erect long setae.Hypomeron not carinate ventrally.Scutellum narrow, long, triangular, with fine but dense punctation and minute setae in punctures, and basally with a triangular smooth area.
Elytra elongate, narrow, widest in posterior third; striae distinctly impressed, finely punctate; intervals weakly convex, finely and densely punctate, with punctures concentrated along striae; elytra glabrous, lateral intervals with a few moderately long, adpressed or erect setae; epipleural margin robust, ending at strongly rounded external apical angle of elytra; epipleura sparsely setose; apex of elytra with a very fine, membraneous rim of short microtrichomes.
Ventral surface finely and densely punctate, glabrous.Metacoxae laterally with a few longer setae.Mesosternum between mesocoxae slightly wider than mesofemur.Ratio of length of metepisternum to metacoxa 1:1.52.Abdominal sternites finely and moderately densely punctate, each with a row of coarse punctures, each puncture bearing each a robust seta.Pygidium almost flat and finely, densely punctate, with moderately dense, long setae.
Legs long, narrow, shiny; femora finely, sparsely punctate, with two longitudinal rows of setae.Metafemur with anterior margin acute, without adjacent serrate line; posterior ventral margin almost straight, weakly widened in apical half, ventrally and dorsally not serrate, sparsely setose.Metatibia long, narrow, widest at apex, ratio of width to length 1:3.9, sharply carinate dorsally, with three groups of spines, basal one at one-third, middle one at three-fifths, apical one at four-fifths of metatibial length, basally with a number of robust single setae; lateral face longitudinally convex, finely and moderately densely punctate, glabrous; apex shallowly, concavely truncate interiorly near tarsal articulation.Ventral edge finely serrate, with four robust equidistant setae.
Tarsomeres finely punctate dorsally, with moderately dense, fine setae ventrally; metatarsomeres ventrally with a strongly serrate carina, subventrally with a second, smooth longitudinal carina; first metatarsomere a little shorter than following two tarsomeres combined, and little shorter than dorsal tibial spur.Protibia long, bidentate; anterior claws symmetrical, interior tarsal claws sharply pointed.
Diagnosis.Serica breviantennalis sp.nov.differs from S. lupina Arrow, 1946 and all other species of this species group in the short antenna and the shape of aedeagus; both parameres are long (subequal to half of the length of phallobase), nearly equal in length, parallel, and basally expanded to basal short lobes.
Etymology.The name of the new species is derived from the combined Latin words brevis (short) and antennalis (antenna), with reference on the short antenna.(An adjective in nominative singular case.) Variation.Length 7.5-8.2mm, elytral length 5.6-6.1 mm, width 4.0-4.3mm.There is some variation of the parameres and lateral intervals of the elytra.Parameres of some specimens are closed, some are slightly open (Fig. 1A-C), and in others turned or rotated outside (Fig. 1E-G).Furthermore, the left paramere is sometimes curved externally (Fig. 1A-C) or sometimes dorsally (Fig. 1E-G).Lateral intervals of the elytra have a few moderately or distinctly dense, long, adpressed or erect setae.Description of the holotype.Length 7.8 mm, elytral length 6.0 mm, width 4.2 mm.Body oblong, light reddish brown; frons reddish brown; some lateral and basal parts of elytra intervals dark reddish brown dull; legs yellowish brown; antenna yellow, with moderately long setae on dorsal surface.Labroclypeus wide, trapezoidal; lateral margins moderately convex and convergent, producing a blunt angle with ocular canthus; anterior angles strongly convex; anterior margin distinctly emarginate medially; margins moderately reflexed; surface moderately convex and finely, densely punctate, with moderately long, erect setae; frontoclypeal suture distinct, moderately curved; ocular canthus moderately narrow (almost 1/3 of ocular width), smooth and glabrous, with one terminal seta.Frons with fine, moderately dense punctures, anteriorly and laterally with a few long setae.Antenna with nine antennomeres; club with three antennomeres, 1.8 times as long as remaining antennomeres combined, slightly reflexed.Eyes moderately large, ratio of diameter to interocular width 0.56.Mentum weakly elevated and flattened anteriorly.A, B, C, E, F, G, I, J, K Pronotum moderately wide, widest at base; lateral margins moderately convex and convergent anteriorly; anterior angles acute, moderately produced, posterior angles blunt; anterior margin weakly convex, marginal line fine but complete; basal margin without marginal line; surface with coarse, dense punctures and minute setae, laterally bearing erect, long setae.Hypomeron not ventrally carinate.Scutellum triangular, with fine but very dense punctation and minute setae, with a triangular smooth area at middle.Elytra elongate, narrow, widest in posterior third; striae distinctly impressed, finely punctate; intervals weakly convex, finely and densely punctate, punctures concentrated along striae; glabrous, lateral intervals with a few moderately long, adpressed or erect setae; epipleural margin robust, ending at strongly rounded external apical angle of elytra; epipleura sparsely setose; apex of elytra with a very fine, membraneous rim of short microtrichomes.

Serica allonanhua
Ventral surface finely and densely punctate, glabrous.Metacoxa laterally with several longer setae.Mesosternum between mesocoxae almost as wide as mesofemur.Ratio of length of metepisternum to metacoxa 1:1.92.Abdominal sternites finely and moderately densely punctate, each with a row of coarse punctures; each puncture bearing a robust seta.Pygidium almost flat and finely, densely punctate, with moderately dense, long setae.
Legs long, narrow, shiny; femora finely and sparsely punctate, with two longitudinal rows of setae, but anterior row reduced to a few setae.Metafemur with anterior margin acute, without adjacent serrate line; posterior ventral margin almost straight, weakly widened in apical half, ventrally and dorsally not serrate, sparsely setose.Metatibia long, narrow, widest at apex, ratio of width to length 1:3.5, moderately carinate dorsally, with three groups of spines, basal one at one-third, middle one at three-fifths, apical one at five-sixths of metatibial length, basally with a number of robust single setae; lateral face longitudinally convex, with fine, moderately dense punctae, glabrous; apex shallowly concavely truncate interiorly near tarsal articulation.Ventral edge finely serrate, with three robust, equidistant setae.Tarsomeres missing.
Diagnosis.Serica allonanhua sp.nov.differs from S. nanhua and all other species of this species group in the light body colour and in the shape of aedeagus: the phallobase is strongly bent, the parameres are moderately long instead of only short (right and left paramere approximately one-third and one-fourth, respectively, as long as phallobase).Compared to S. nanhua, the parameres are distinctly longer, and in contrast to S. baishuitaiensis the parameres are straight in lateral view and narrow; the left paramere is slightly shorter than right one.
Etymology.The name of the new species is derived from the combination of the Greek prefix allo-(different, other) and nanhua, in reference to the similarity of the new species to Serica nanhua.(Used as a noun in apposition.) Variation.Female Length 7.6 mm, elytral length 5.8 mm, width 4.1 mm.Antennal club short, slightly shorter than remaining antennomeres combined; eyes smaller than in male, ratio of diameter to interocular width 1:0.40; pygidium weakly convex, ratio of metepisternum to metacoxa 1:1.57; ratio of width to length of metatarsomeres 1:4.1.Tarsomeres dorsally finely punctate, ventrally with moderately dense, fine setae; metatarsomeres ventrally with a distinct serrate carina, subventrally with a second smooth, longitudinal carina; first metatarsomere a little shorter than following two tarsomeres combined and almost as long as dorsal tibial spur.Protibia long, bidentate; anterior claws symmetrical; interior tarsal claws sharply pointed.

Serica fengensis
Labroclypeus wide, trapezoidal, shiny; lateral margins moderately convex and convergent, producing a blunt angle with ocular canthus; anterior angles moderately convex; anterior margin distinctly emarginate medially; margins moderately reflexed; surface flat, finely and densely punctate, with numerous long and erect setae; frontoclypeal suture distinct, moderately curved; ocular canthus long and narrow (ca 1/3 of ocular width), smooth and glabrous, with two terminal setae.Frons dull, with fine, dense punctures and dense, long, erect setae.Antenna with nine antennomeres; club with three antennomeres, 2.5 times as long as remaining antennomeres combined, strongly reflexed.Eyes moderately large, ratio of diameter to interocular width 0.67.Mentum weakly elevated and anteriorly flattened.
Pronotum moderately wide, widest at middle; lateral margins moderately convex and convergent anteriorly, slightly narrowed towards base; anterior angles rectangular, moderately produced, posterior angles blunt; anterior margin weakly convex, marginal line fine and complete; basal margin without marginal line; surface with fine, dense punctures and minute setae in punctures, with sparse, erect, long setae.Hypomeron not ventrally carinate.Scutellum triangular, with fine, dense punctation and minute setae; basal midline with a triangular smooth area.
Elytra elongate, narrow, widest in posterior third; striae distinctly impressed, finely punctate; intervals weakly convex and finely, densely punctate; glabrous, lateral intervals with a few moderately long, erect setae, otherwise with only minute setae in punctures; epipleural margin robust, ending at convex external apical angle of elytra; epipleura sparsely setose; apex of elytra with a fine, membraneous rim of short microtrichomes.

A B C D E
Ventral surface finely, densely punctate, and metasternum sparsely setose.Metacoxa glabrous, laterally with numerous, robust, fine, longer setae.Mesosternum between mesocoxae almost as wide as mesofemur.Ratio of length of metepisternum to metacoxa 1:1.52.Abdominal sternites finely, moderately, and densely punctate, each sternite with a row of coarse punctures, each puncture bearing a robust seta.Pygidium almost flat and finely, densely punctate, with moderately dense, short and long setae.
Legs long, narrow, shiny; femora finely, sparsely punctate, with two longitudinal rows of setae, but anterior row reduced to a few setae.Hind legs missing in holotype.Tarsomeres dorsally finely punctate, ventrally with moderately dense, fine setae.Protibia long, bidentate; anterior claws symmetrical; interior tarsal claws sharply pointed.
Diagnosis.Serica fengensis sp.nov.differs from the quite similar S. allonanhua sp.nov. in the long basal lobes of the parameres; these lobes are absent in the latter species.
Etymology.The name of the new species is derived from the location of type locality in Feng County.(Used as an adjective in nominative singular case.) Variation.Length 6.8-8.4 mm, elytral length 5.3-6.5 mm, width 3.8-4.0mm.Most paratypes with dense pilosity on pronotum and elytra, suggesting that pilosity of holotype has been widely abraded.Metafemur with anterior margin acute, without adjacent serrate line; posterior ventral margin almost straight, weakly widened in apical half, ventrally and dorsally not serrate, sparsely setose.Metatibia long and moderately narrow, widest at middle, ratio of width to length 1:3.3, dorsally sharply carinate, with two groups of spines, basal one shortly behind middle, apical one at four-fifths of metatibial length, basally with a number of robust, single setae in line; lateral face longitudinally convex, coarsely and densely punctate, with a numerous short setae in basal half; apex shallowly concavely truncate interiorly near tarsal articulation.Ventral margin finely serrate, with five or six robust equidistant setae.Metatarsomeres ventrally with a strongly serrate carina, subventrally with a second, smooth, longitudinal carina; first metatarsomere distinctly shorter than following two tarsomeres combined and little longer than dorsal tibial spur.