Gynaecoserica pseudocymosa Ahrens, 2021

Ahrens, Dirk, 2021, New species of the genus Gynaecoserica Brenske, 1896 from Indochina (Coleoptera: Scarabaeidae: Sericini), Zootaxa 5005 (2), pp. 218-226 : 223-224

Gynaecoserica pseudocymosa Ahrens , new species

Fig. 2A–D

Type material examined. Holotype ♂ “Thai 1-8.v.1993 Soppong Pai 1800m Pacholátko & Dembicky leg. / TS12 / Asia Sericini sp. 24” ( CPPB).

Description of the holotype, male. Length: 4.1 mm, length of elytra: 2.4 mm, width: 2.1 mm. Body oblong, dorsal surface yellowish brown, anterior half of pronotum brown, margins of elytra black, frons dark greenish brown, antenna and legs yellow, except shiny head dorsal surface dull, sparsely setose.

Labroclypeus widest at base, subsemicircular, lateral margins strongly convex, anterior angles strongly convex, lateral border and ocular canthus producing a distinct blunt angle; margins weakly reflexed; anterior margin very shallowly sinuate medially; surface flat and shiny, finely and densely punctate, distance between punctures less than their diameter, with a transversal raw of a few coarser punctures behind anterior margin each bearing a long, erect seta; frontoclypeal suture feebly incised and curved; smooth area in front of eye little wider than long; ocular canthus short and slender (length subequal 1/4 of ocular diameter), impunctate, with a short terminal seta. Frons shiny, with fine, dense punctures, glabrous except some short erect setae beside eyes. Eyes small, ratio of diameter/ interocular width: 0.5. Antenna yellow, with ten antennomeres; club dark, with six antennomeres, slightly reflexed, 1.3 times as long as the remaining antennomeres combined. Mentum weakly elevated and flattened anteriorly.

Pronotum moderately wide, widest at base, lateral margins subparallel and straight in basal half, in anterior half weakly curved and convergent anteriorly, anterior angles moderately produced and sharp, posterior angles blunt; anterior margin convexly produced medially, with a distinct fine marginal line, basal margin without marginal line; anterior and lateral margins glabrous; surface with moderately dense and fine punctures, with microscopic white setae in punctures, otherwise glabrous; hypomeron distinctly carinate at base but not ventrally produced. Scutellum narrow and short, triangular, with sparse, fine punctures, punctures with microscopic setae.

Elytra moderately long, widest shortly at middle, striae weakly impressed, finely and densely punctate; intervals weakly convex, with fine and moderately dense punctures concentrated along striae, punctures with minute white adjacent setae, odd intervals with a few single robust, white, adjacent setae; interior apical angle of elytra with a strong seta; epipleural edge fine ending at strongly curved external apical angle of elytra; epipleura sparsely setose, apical border without short microtrichomes (at magnification 100x).

Ventral surface dull, with fine and moderately dense punctures, sparsely setose; metacoxa only laterally with a few strong adjacent setae. Each abdominal sternite with indistinct transverse row of coarse punctures bearing short setae between fine, dense punctation. Mesosternum between mesocoxae as wide as mesofemur, with irregularly scattered very strong setae. Ratio of length of metepisternum/ metacoxa: 1/ 1.67. Pygidium weakly convex, coarsely and densely punctate, without smooth midline, completely dull, with long setae beside apical margin.

Legs moderately slender and long; femora dull, with two longitudinal rows of setae, finely and sparsely punctate; metafemur shiny, sharply margined anteriorly and without a submarginal serrate line, posterior margin weakly convex and glabrous, its external (ventral) part only weakly widened in apical half and not serrate, internally (dorsally) finely serrate, with short setae. Metatibia slender and moderately long, widest at middle of metatibial length, ratio width/ length: 1/ 3.3, dorsally sharply carinate, with two groups of spines, basal one at anterior third, apical one at two thirds of metatibial length, basally nearly glabrous; external face longitudinally convex, with sparse and fine punctures, glabrous; ventral margin carinate and serrate, with three strong spines, of which the two distal are widely separated; internal face very finely and sparsely punctate; apex interiorly near tarsal articulation sharply and deeply truncate. Tarsomeres dorsally glabrous and impunctate, ventrally with sparse, short setae; metatarsomeres ventrally with a strongly serrate ridge, beside which is a fine longitudinal carina; first metatarsomere little shorter than two following tarsomeres combined and little less than twice as long as dorsal tibial spur. Protibia moderately long, bidentate, protarsal claws symmetrical.

Aedeagus: Fig. 2A–C . Habitus: Fig. 2D .

Female unknown.

Diagnosis. Gynaecoserica pseudocymosa Ahrens , new species differs from Gynaecoserica fallaciosa Ahrens , new species and G. feresimplex Ahrens, new species by the longer, reflexed antennal club, the bicolored body, and the shape of the aedeagus: phallobase with a short apical process at the left side, the right paramere is much wider (in the holotype, the tip of left paramere is narrow, but broken (glued separately to the aedeagus).

Etymology. The name of the new species (adjective in nominative singular case) is derived from the combined Greek prefix pseudo- (nearly) and the species name cymosa , with reference to its similarity in external appearance with Gynaecoserica cymosa (Brenske, 1896) .

Figures

FIGURE 2. A–C: Gynaecoserica pseudocymosa Ahrens, new species (holotype); E–H: G. ottoi Ahrens, new species (holotype). A, E: aedeagus, left side lateral view; C, G: aedeagus, right side lateral view; B, F: parameres, dorsal view; D, H: habitus. Scale: 0.5 mm. Habitus not to scale.