Tetraserica Ahrens, 2004

Liu, Wan-Gang, Fabrizi, Silvia, Bai, Ming, Yang, Xing-Ke & Ahrens, Dirk, 2014, A taxonomic review on the species of Tetraserica Ahrens, 2004, of China (Coleoptera, Scarabaeidae, Sericini), ZooKeys 448, pp. 83-121 : 84-85

Taxon classification Animalia Coleoptera Scarabaeidae

Tetraserica Ahrens, 2004

Tetraserica Ahrens, 2004: 168 (type species by original designation: Neoserica gestroi Brenske, 1898).

Diagnosis.

Body moderately large to large (6-12 mm), mostly dark brown; ventral surface reddish brown; dorsal surface dull and glabrous.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins moderately convex and convergent to strongly rounded anterior angles, anterior margin weakly sinuate medially, margins moderately reflexed; surface weakly convex, moderately shiny, finely and densely punctate; frontoclypeal suture indistinctly incised, flat and weakly curved medially; ocular canthus short and triangular, impunctate, with a single terminal seta. Frons dull, with sparse, fine punctures, with single erect setae beside each eye. Antenna yellowish, with 10 antennomeres; club composed of 4 antennomeres in male, straight, rarely longer than 1.5 times as the remaining antennomeres combined; club in female composed of 3 antennomeres, as long as the remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately wide and strongly convex, lateral margins evenly convex, more strongly narrowed anteriorly towards sharp and slightly produced anterior angles. Anterior margin of pronotum slightly convex, with fine complete marginal line. Posterior angles blunt or strongly rounded. Surface finely and densely punctate, except minute setae glabrous, lateral and lateral anterior margins sparsely setose. Hypomeron not carinate. Scutellum triangular, finely and densely punctate.

Elytra oblong, widest just behind middle, striae distinctly impressed, finely and moderately densely punctate, intervals distinctly convex, with coarse and dense punctures concentrated along striae, with very minute setae in punctures; epipleural edge robust, ending at weakly curved and slightly blunt external apical angle of elytra, epipleura densely setose, apical border with a broad fringe of microtrichomes (100 ×).

Ventral surface weakly shiny, finely and densely punctate, metasternum sparsely covered with fine, short, or very minute setae, metacoxa glabrous, with a few single setae laterally; abdominal sternites finely and densely punctuate, with a transverse row of coarse punctures, each bearing a robust seta. Mesosternum between mesocoxae as wide as mesofemur. Pygidium weakly convex and dull, densely punctate, without smooth midline, almost glabrous, but with a few longer setae along apical margin; pygidium without strong sexual dimorphism.

Legs moderately wide; femora finely and sparsely punctate; metafemur wide and moderately shiny or dull, anterior margin acute, posterior margin smooth ventrally and only weakly widened in apical half, posterior margin smooth dorsally, with a few short setae basally. Metatibia moderately wide to wide and moderately long, widest at half of metatibial length, dorsal margin sharply carinate, with two groups of spines; lateral face finely and sparsely punctate; ventral edge finely serrated, with four robust equidistant setae, medial face smooth, apex interiorly near tarsal articulation with a shallow sinuation. Tarsomeres with fine, very dense setae ventrally on distal half, neither laterally nor dorsally carinate, dorsally smooth; metatarsomeres with a strongly serrated ridge ventrally and glabrous; first metatarsomere slightly shorter than two following tarsomeres combined, one third of its length longer than dorsal tibial spine. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedoeagus. Phallobasis with a more or less long median ventral extension.

Remarks.

So far seven species from Himalaya and the type species from Myanmar have been formally assigned to Tetraserica ( Ahrens 2004; Ahrens and Fabrizi 2009). Most other oriental species (so far grouped with ' Neoserica ') await taxonomic revision. Tetraserica differs from closely related genera Microserica Brenske, 1894, and Trioserica Moser, 1922, by the lacking ventral carina of hypomeron. From Microserica it also differs by the lacking sexual dimorphism of the pygidium, from Trioserica by the bidentate protibia. In contrast to the Microserica , species of Tetraserica are active at night and are attracted by light.

Distribution.

The genus is distributed almost in the entire Oriental region; we know described species so far assigned to " Neoserica " from Philippines, Indochina, Sumatra, and Borneo ( Ahrens 2004). Except in Meghalaya and Himalaya, the genus does not occur on Indian subcontinent south of the Ganges.

Key to the Chinese species of Tetraserica (♂♂)