Neoserica (s.l.) tahianensis Ahrens, Fabrizi & Liu

Liu, Wan-Gang, Fabrizi, Silvia, Bai, Ming & Ahrens, Dirk, 2016, A taxonomic revision of Neoserica (sensu lato): the species groups N. lubrica, N. obscura, and N. silvestris (Coleoptera, Scarabaeidae, Sericini), ZooKeys 635, pp. 123-160 : 143-147

Neoserica (s.l.) tahianensis Ahrens, Fabrizi & Liu sp. n. Figs 4 A–D, 6

Type material examined.

Holotype: ♂ "Hainan I. (C.): Ta Hian (TaSianKwang) 600m. VI-10-35 J.L. Gressitt" (BPBM). Paratypes: 1 ♂, 1 ♀ "Yinggen, Hainan, Guangdong, 10.VII.1960, 200m, leg. Zhang Xuezhong" (IZAS), 1 ♂ "Tongshi, Hainan, Guangdong, 31.VII.1960, 340m, leg. Li Suofu" (IZAS), 3 ♂♂, 3 ♀♀ "Shuiman, Hainan, Guangdong, 29.V.1960, 640m, leg. Zhang Xuezhong" (IZAS, ZFMK), 1 ♂ "Tongshi, Hainan, Guangdong, 6.VIII.1960, 340m, leg. Li Suofu" (IZAS).

Diagnosis.

Neoserica tahianensis Ahrens, Fabrizi & Liu, sp. n. is in external appearance and genital morphology similar to Neoserica obscura and Neoserica allobscura . Neoserica tahianensis differs by the large ventral process of the phallobase and by the shape of its parameres: the right paramere is slightly longer than in Neoserica obscura , the left one does not possess a dorsal lobe.

Description.

Body length: 6.5 mm, length of elytra: 4.3 mm, body width: 4.3 mm. Body short-oval, dark brown, elytra black, abdomen dark brown, dorsal surface except anterior labroclypeus dull, head and pronotum with some greenish shine, pronotum and elytra glabrous.

Labroclypeus subtrapezoidal, distinctly wider than long, widest at base, lateral margins weakly convex, convergent anteriorly; anterior angles strongly rounded; anterior margin shallowly sinuate medially, margins moderately reflexed; surface weakly convex, shiny, base dull, finely and densely punctate, mixed with a few larger punctures bearing each an erect seta; frontoclypeal suture distinctly incised, weakly curved medially; smooth area in front of eye convex, nearly as long as wide; ocular canthus short and triangular (1/3 of ocular diameter), sparsely punctate, without terminal seta. Frons with fine and moderately dense punctures, with a few long erect setae beside eyes and behind lateral frontoclypeal suture. Eyes small, ratio diameter/ interocular width: 0.42. Antenna with ten antennomeres, club (♂) with four antennomeres and straight, slightly longer than remaining antennomeres combined. Mentum convexly elevated and flattened anteriorly.

Pronotum transverse, widest at base, lateral margins evenly convex and moderately convergent anteriorly; anterior angles distinctly produced and sharp, posterior angles blunt and weakly rounded at tip; anterior margin straight, with a fine complete marginal line; surface densely and finely punctate, glabrous, with minute setae in punctures (100 × magnification); lateral border densely setose; hypomeron distinctly carinate basally, not produced ventrally. Scutellum triangular, with fine, dense punctures, glabrous.

Elytra short-oval, widest shortly behind middle, striae finely impressed, finely and densely punctate, intervals weakly convex, with sparse, fine punctures concentrated along striae, except a few robust setae on sutural interval glabrous; epipleural edge robust, ending at nearly blunt external apical angle of elytra, epipleura densely setose; apical border without a fine fringe of microtrichomes (visible at 100 × magnification).

Ventral surface dull, finely and densely punctate; metasternum nearly glabrous except a few long robust setae on disc, punctures with minute setae (100 × magnification); metacoxa glabrous, with a few single setae laterally; abdominal sternites finely and densely punctate, with a transverse row of coarse punctures, each bearing a short robust seta, last sternite half as long as penultimate one. Mesosternum between mesocoxae as wide as the mesofemur, with a semi-circular ridge bearing long setae. Ratio of length of metepisternum/ metacoxa: 1/ 2.2. Pygidium dull, moderately convex, coarsely and densely punctate, without smooth midline, with a few long setae along apical margin.

Legs short; femora moderately shiny, with two rudimentary longitudinal rows of setae, finely and sparsely punctate, glabrous; metafemur with anterior margin acute, without serrated line behind anterior edge, posterior margin smooth ventrally, in apical half only weakly widened, posterior margin smooth dorsally. Metatibia wide and short, widest at middle, ratio of width/ length: 1/ 2.7; dorsal margin sharply carinate, with two groups of spines, basal group at one third, apical group at three quarters of metatibial length, basally with a few short single setae; lateral face weakly convex, finely and sparsely punctate; ventral edge finely serrated, with three robust nearly equidistant setae; medial face smooth, apex interiorly near tarsal articulation bluntly truncate and slightly concavely sinuate. Tarsomeres ventrally with sparse, short setae, smooth, neither laterally nor dorsally carinate; metatarsomeres with a strongly serrated ridge ventrally, glabrous; first metatarsomere slightly shorter than following two tarsomeres combined and slightly shorter than dorsal tibial spur. Protibia short, bidentate, distal tooth sharply pointed at apex; anterior claws symmetrical, basal tooth of inner claw sharply truncate at apex.

Aedeagus: Fig. 4 A–C. Habitus: Fig. 4D.

Etymology.

The name of the new species is derived from the type locality, Ta Hian.

Variation.

Body length: 6.5-7.1 mm, length of elytra: 4.3-4.6 mm, body width: 4.3-4.7 mm. Colour varies from entirely reddish brown to nearly completely black, often reddish elytra and pronotum with a dark margin. Female: Antennal club composed of 4 antennomeres, first joint of club slightly shorter than the club, club slightly shorter than remaining antennomeres combined.