Serica (Taiwanoserica) yangzaichuni 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 : 207-208

Serica (Taiwanoserica) yangzaichuni Zhao & Ahrens , new species

( Figs 8D , 9D )

Type material examined. Holotype. ♂ ( SCAU), “ CHINA: Guizhou, Mt. Leigongshan, Lianhuaping, Xiannütang , 1555 m, 26°22′22.77″N, 108°11′52.23″E, 22–23.VII.2017 Ming-Zhi Zhao leg. at light” . Paratypes. 6♂♂ ( CZMZ), “ CHINA: Guizhou, Mt. Leigongshan, Lianhuaping, Xiannütang , 1555 m, 26°22′22.77″N, 108°11′52.23″E, 22– 23.VII.2017 Ming-Zhi Zhao leg. at light” .

Description of the holotype. General. Body elongated ovoid, moderately convex; color yellowish brown, ventral surface including metacoxa with thick tomentum and iridescent; head (except for dull frons) smooth; pronotum, scutellum and pygidium weakly dull and iridescent, with irregular green patterns; legs reddish brown, palpi and antennae yellowish brown, shiny. Setae pale.

Head. Labroclypeus subtrapezoidal, distinctly wider than long, widest at base, ratio of maximum length/ width: 1/ 1.75; lateral margins almost straight, weakly convergent anteriad, anterior angles blunt, anterior margin widely and strongly concave; margins moderately reflexed; surface flat, with dense and coarse punctures and some short, erect setae; frontoclypeal suture finely incised, curved medially; smooth area anterior to eye large and flat, approximately 1.75 times as wide as long; ocular canthus slender (equal to 1/3 of ocular diameter), with a short terminal seta. Frons tomentum and flat, sparsely and finely punctate, with some short erect setae. Eyes small, ratio diameter/ interocular width: 0.55. Antenna with ten antennomeres; antennomeres 3 to 5 equally as wide as long, antennomere 6 slightly wider than long, antennomere 7 transverse and short; club straight, with three antennomeres, 1.5 times longer than remaining antennomeres combined. Mentum strongly and transversely elevated anteriorly. Labrum transverse, strongly produced, narrowly concave medially.

Pronotum subrectangular, widest at middle, lateral margins strongly reflexed; anterior angle distinctly produced and acute, posterior angle broadly rounded; hypomeron carinate at base but not produced ventrally; anterior margin with a fine marginal line; surface with moderately dense and large punctures, posterior half with a Y-shaped, impunctate area; disc with sparse and lanceolate setae, anterior half medially with some recumbent short setae, posterior margin anterior to scutellum and near posterior angle with some recumbent minute setae, anterior and lateral margins with sparse, erect and moderately long setae.

Scutellum large, triangular, apex somewhat rounded; basomedial portion impunctate, otherwise with dense and small punctures, with dense and minute setae beside lateral margin.

Elytra elongated, widest shortly after middle. Striae distinctly impressed, strial punctures dense and large; intervals weakly convex, with irregularly distributed and large punctures, with sparse and lanceolate seta, numerous of recumbent minute setae, and a single semi-erect, long setae near base; dark patterns irregular and generally impunctate, with dull tomentum. Epipleura ending shortly before moderately curved external apical angle of elytron, with a row of dense, erect, and moderately long setae, elytral apex with a short seta, apical margin with a very fine membranous rim composed of microtrichomes.

Ventral thoracic surface and metacoxae with dense and large punctures, anterior half of ventral thoracic surface with moderately dense, short setae, hypomeron sparsely setose, metacoxae laterally with a few short, spiniform setae. Mesosternum between mesocoxae slightly narrower than width of mesofemur. Ratio of length of metepisternum/ metacoxa: 1/ 1.46.

Abdomen. Abdominal ventrites with moderately dense and small punctures, each ventrite with a transverse row of punctures each bearing a short seta, penultimate ventrite medially with several moderately long setae, ultimate ventrite medially as long as penultimate one and with a tuft of moderately long setae and a transverse row of minute setae near posterior margin. Pygidium weakly convex, posterior margin moderately reflexed; with dense and small punctures, irregular and impunctate dark patterns aggregated at basal half, surface evenly covered by sparse, short to moderately long setae.

Femora. Profemur shiny, with a row of moderately long setae near dorsal margin. Mesofemur dull, two longitudinal rows of moderately dense punctures each bearing a short seta. Metafemur shiny, with moderately dense punctures, two longitudinal rows of punctures each bearing a short seta; anterior margin moderately sharp, ventral posterior margin serrate at apical third, dorsal posterior margin completely serrate, a row of minute to short setae situated between latter two margins, irregularly doubled near apex.

Tibiae. Protibia moderately long, bidentate, tibial teeth protruding and acute, mesial external margin weakly convex. Metatibia widest shortly before apex, ratio of width/ length: 1/ 3.75; dorsal margin not carinate; lateral face with scattered and small punctures and two groups of small but spiniform setae not touching the dorsal margin, basal group shortly before middle, distal group at three quarters of metatibial length, in basal third with several smaller spiniform setae; ventral margin serrate except for basal third, with three spiniform setae of which the distal two are more distant; medial face finely and sparsely punctate; apex interiorly serrate, near tarsal articulation bluntly truncate.

Tarsi. Protarsomeres short, pro- and mesotarsomeres with moderately dense and minute setae ventrally. Meso- and metatarsomeres serrate ventrally. Metatarsomeres not carinate laterally, first metatarsomere as long as following two tarsomeres combined and twice as long as dorsal tibial spur. Protarsal claws symmetric, basal tooth slightly wider than distal one.

Male genitalia. Fig. 9D .

Variation. Male. Dark patterns are variable, sometimes very sparse on pygidium.

Female. Unknown.

Measurements. Length: 7.8–8.2 mm in males (holotype 8.2 mm); length of elytra: 5.6–6.1 mm in males (holotype 5.8 mm); width: 4.4–4.5 mm in males (holotype 4.4 mm).

Diagnosis. Serica yangzaichuni Zhao & Ahrens , new species is similar to S. huangjing Ahrens, Fabrizi & Liu, 2022 and S. limbourgi Ahrens, Fabrizi & Liu, 2022 . Serica yangzaichuni differs from S. huangjing by the more strongly curved dorsal lobe of left paramere having an expanded apex and the shorter dorsal lobe of the right paramere. The phallobase of S. limbourgi bears a large ventral protuberance which is absent in either S. yangzaichuni or S. huangjing . Serica limbourgi differs also by the slenderer, longer and strongly curved dorsal lobe of the right paramere from S. yangzaichuni as well as from S. huangjing .

Etymology. The species name is dedicated to Dr. Zai-Chun Yang, who kindly assisted the first authors during the survey in Mount Leigongshan in 2016 and 2017.

Figures

FIGURE 8. Habitus indorsal view.A, Serica (s. l.) longidentata Zhao &Ahrens,new species,holotype; B, S. (s. l.) callosericoides Zhao & Ahrens, new species, holotype; C, S. (Taiwanoserica) liboyani Zhao & Ahrens, new species, holotype; D, S. (T.) yangzaichuni Zhao & Ahrens, new species, holotype. Scale bar = 5 mm.

FIGURE 9. Aedeagus. A, Serica (s. l.) longidentata Zhao & Ahrens, new species, holotype; B, S. (s. l.) callosericoides Zhao & Ahrens, new species, holotype; C, S. (Taiwanoserica) liboyani Zhao & Ahrens, new species, holotype; D, S. (T.) yangzaichuni Zhao & Ahrens, new species, holotype. a, aedeagus in left lateral view; b, parameres in dorsal view; c, aedeagus in right lateral view. Scale bar = 1 mm.