Gastroserica (s. str.) mayunshui Zhao & Ahrens, 2023

Zhao, Ming-Zhi & Ahrens, Dirk, 2023, New species of the tribe Sericini Kirby, 1837 from China, with further updates on their taxonomy and distribution (Coleoptera: Scarabaeidae: Sericinae), Zootaxa 5361 (2), pp. 181-220 : 182-184

Gastroserica (s. str.) mayunshui Zhao & Ahrens , new species

( Figs 1A , 2A )

Type material examined. Holotype. ♂ ( SCAU), “ CHINA: Guangdong, Shaoguan , Nanling N. R., nr. Shikengkong, N 24°55′40″, E 112°59′2″, 1660 m, 30.V–4.VI.2022 (at light), lgt. Ye XH, Zhan BX & Ma YS” . Paratypes. 1♂ ( SCAU), “ CHINA: Guangdong, Shaoguan, Nanling N. R., Xiaohuangshan, N 24°53′44″, E 113°1′35″, 1207 m, 30.V.2022 (at light), lgt. Ye XH, Zhan BX & Ma YS”; 2♂♂ ( SCAU), “ Guangdong, Nanling Nature Reserve, 2016- VI-29–31 ”; 10♂♂, 2♀♀ ( CZMZ), “ CHINA: GUANGDONG, Nanling Nature Reserve , 960 – 1189 m, 22–26.V.2021, Yun-Shu Ma leg.”.

Description of the holotype. General. Body shape elongated ovoid, strongly convex, without metallic luster; abdomen, antennae and legs shiny. Body yellowish brown, iridescent, abdomen and anterior portions of metatibia darker; frons, two large, rectangular dark spots on each side of pronotum, and two longitudinal bands on each side of elytron, as well as anterolateral portions of ventral metathoracic surface greenish brown; antennal clubs and a small spot near lateral margin of pronotum dark brown. Spiniform setae reddish brown, other setae yellowish brown.

Head. Labroclypeus subrectangular, ratio of maximum length/ width: 1/ 1.8; lateral margins straight and subparallel, anterior angle broadly rounded, anterior margin almost straight; margins moderately reflexed, weakly prominent medially; surface flat, with moderately dense and large punctures, slightly wrinkled behind anterior margin, with several short erect setae; frontoclypeal suture finely incised, curved medially; smooth area anterior to eye large and flat, slightly wider than long; ocular canthus short (distinctly shorter than 1/3 of ocular diameter), bearing a short terminal seta. Frons flat, punctate as on labroclypeus, most of the punctures each bearing a minute recumbent seta, mixed with some short erect setae. Eyes small, ratio diameter/ interocular width: 0.52. Antenna with ten antennomeres, antennomeres 5 equally as wide as long, antennomere 6 triangular; club straight, with four antennomeres, 1.3 times as long as remaining antennomeres combined. Mentum moderately and transversely elevated anteriorly. Labrum weakly produced, shallowly concave medially.

Pronotum subtrapezoidal, widest at base, concave medially; lateral margins weakly concave and convergent anteriad in posterior half, strongly convergent anteriad in anterior half; anterior angle obsolete, posterior angle fused with the posterior angle of hypomeron, forming a broadly rounded angle, hypomeron carinate at base and strongly produced ventrally; anterior margin with a complete and fine marginal line; surface with dense and large punctures, each bearing a minute recumbent seta, anterior and lateral margins with long erect setae.

Scutellum elongated triangular, apex rounded; longitudinal midline impunctate and slightly convex, lateral portions with dense and small punctures bearing each a minute recumbent seta.

Elytra oval, side somewhat subparallel, widest at middle. Striae strongly impressed, strial punctures dense and large; intervals moderately convex, two innermost intervals as well as epipleura with scattered and small punctures; punctures are all setose, setae minute and recumbent, sparsely interspersed with long erect ones, longer and spiniform near suture and at apex. Epipleura wide and abruptly ending after the moderately curved external apical angle, with a row of large punctures each bearing a robust seta. Posterior margin without membranous rim.

Ventral thoracic surface. The entire ventral thoracic surface including metacoxa with dense punctures, each bearing a recumbent and short seta, punctures on hypomeron being smaller and sparser, lateral margins of metepisternum and metacoxa with a few short spiniform setae. Mesosternum between mesocoxae approximately 1.5 times wider than width of the mesofemur, posterior margin of mesosternum somewhat vertically convex and arched, with dense, short and spiniform setae. Ratio of length of metepisternum/ metacoxa: 1/ 1.9.

Abdomen. Abdominal ventrites with very dense and small punctures, each bearing a short recumbent seta, setae become longer medially, each ventrite shortly behind middle with a transverse row of short and spiniform setae, spiniform setae moderately long on penultimate ventrite and lacking on ultimate ventrite. Posterior margin of ventrite 3 strongly rimmed medially, ultimate ventrite medially almost as long as penultimate one. Pygidium strongly tumid near apex, posterior margin rather weakly reflexed; punctate and setose as in ultimate abdominal ventrite, but the long setae are sparser.

Femora. Profemur with a row of moderately long setae near anterior margin. Mesofemur with moderately dense and small punctures each bearing a short seta. Metafemur punctate and setose as mesofemur; anterior margin sharp, ventral posterior margin carinate at distal third, dorsal posterior margin finely and completely serrate, several moderately long setae situated between the latter two margins.

Tibiae. Protibia stout and bidentate, tibial teeth acute. Metatibia widest at middle, ratio of width/ length: 1/ 3.5; dorsal margin strongly carinate; lateral face densely and finely punctate, each puncture bearing a minute recumbent seta, dorsally with two groups of spiniform setae not touching dorsal margin, equally-spaced on metatibial length, basal fifth with two short setae; ventral margin convex, serrate at distal two fifths, with four equidistant, long and spiniform setae, basally with some short setae; medial face impunctate; apex interiorly oblique and serrate, near tarsal articulation shallowly concave.

Tarsi. Protarsomeres short, pro- and mesotarsomeres with moderately dense and minute setae ventrally, metatarsomeres scarcely setose ventrally. All metatarsomeres carinate dorsally and laterally, strongly serrate ventrally, metatarsomere 1 as long as following two tarsomeres combined and twice as long as dorsal tibial spur. Protarsal claws symmetric, basal tooth wide and truncate at apex. Basal teeth of meso- and metatarsal claws narrower than that of protarsal claw.

Aedeagus. Fig. 2A .

Variation. Male. The green portions on some specimens turn out to be brownish or reddish, indistinctly contrast to body color. Female. Eyes as large as male. Antennal club shorter, equal to remaining antennomeres combined; pygidium less convex at disc; ventral lobe of each tarsal claw somewhat acute at apex.

Measurements. Length: 6.8–7.9 mm in males (holotype 7.2 mm), 7.6–8.5 mm in females; length of elytra: 4.3–5.6 mm in males (holotype 5.0 mm), 5.2–5.9 mm in females; width: 3.7–4.2 mm in males (holotype 3.9 mm), 3.9–4.4 mm in females.

Diagnosis. Gastroserica (s. str.) mayunshui Zhao & Ahrens , new species is very similar to G. (s. str.) haoyui Liu & Ahrens, 2014 from Zhejiang. However, in the new species the longer lobe of left paramere is straight and spikeshaped, while it is S-shaped and robust in G. haoyui .

Etymology. The species name is dedicated to Mr. Yun-Shu Ma, who collected the majority of the type series.

Figures

FIGURE 1. Habitus in dorsal view. A, Gastroserica (s. str.) mayunshui Zhao & Ahrens, new species, holotype; B, G. (s. str.) yunnanensis Liu, Ahrens, Bai & Yang, 2011, male (Guangdong); C, Pachyserica albopunctata Zhao & Ahrens, new species, holotype; D, P. albopunctata, female paratype; E, Amiserica lii Ahrens, 2003, female (Hunan); F, A. lii, male (Hunan). Scale bar = 5 mm.

FIGURE 2. Aedeagus. A, Gastroserica (s. str.) mayunshui Zhao &Ahrens, new species, holotype; B, G. (s. str.) yunnanensis Liu, Ahrens, Bai & Yang, 2011 (Guangdong); C, Amiserica lii Ahrens, 2003 (Hunan); D, M. aureola (Murayama, 1938) (Hunan); E, P. albopunctata Zhao & Ahrens, new species, holotype. a, aedeagus in left lateral view; b, parameres in dorsal view; c, aedeagus in right lateral view; d, aedeagus in dorsal view. Scale bar = 1 mm.