Amiserica venxianensis Ahrens, Fabrizi & Liu, 2021

Ahrens, Dirk, Liu, Wangang, Pham, Phu Van & Fabrizi, Silvia, 2021, An overview on the genus Amiserica Nomura, 1974 (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5050 (1), pp. 1-63 : 43-45

Amiserica venxianensis Ahrens, Fabrizi & Liu , new species

Figures 11A–D , 18

Type material examined. Holotype: ♂ “ China South Gansu Venxian env. 18–26.6.95 Benes / 774 Sericini : Asia spec.” ( ZFMK) . Paratypes: 1 ♂ “ Miaotaizi, Liuba , Shaanxi, 1.VII.1999, 1470m, leg. He Tongli / LW-237” ( IZAS) , 1 ♂ “ Huoditang , Shaanxi, 23.VII.1979, leg. Han Yinheng ” ( IZAS) , 1 ♂ “ Huoditang, Ningshan , Shaanxi, 30.VII.1979, 1620m, leg. Han Yinheng / LW-795” ( IZAS) .

Description of the holotype. Length: 7.2 mm, length of elytra: 5.1 mm, width: 4.0 mm. Body oblong, dark reddish brown, surface shiny, labroclypeus shiny, antenna yellowish brown, dorsal surface almost glabrous.

Labroclypeus subtrapezoidal, widest at base, lateral margins weakly convex and convergent to moderately rounded anterior angles, lateral border and ocular canthus producing a distinct angle; anterior margin weakly emarginate medially, margins moderately reflexed; surface convex and shiny, finely and irregularly, moderately densely punctate, with a few long erect setae in anterior part; frontoclypeal suture finely incised, angled medially; smooth area anterior to eye three times as wide as long. Ocular canthus short and wide, finely and sparsely punctate, with a short terminal seta, equal to 1/3 of ocular diameter. Frons finely and densely punctate, with a few long setae beside eyes. Eyes moderately large, ratio of diameter/interocular width: 0.62. Antenna with nine antennomeres, club with three antennomeres, reflexed, 1.5 times as long as remaining antennomeres combined. Mentum elevated and flattened anteriorly.

Pronotum widest at base, lateral margins in basal half straight and subparallel, in anterior part strongly curved and convergent to moderately produced and blunt anterior angles, posterior angles blunt; anterior margin distinctly convex, with the marginal line very narrowly interrupted at middle; basal margin without marginal line; surface with partly dense and fine punctures, glabrous, only on side punctures bearing an extremely minute seta; anterior and lateral borders sparsely setose; hypomeron carinate, basal margin of hypomeron not produced ventrally. Scutellum triangular, apex sharp, with fine and dense punctures, glabrous.

Elytra oblong, widest in posterior third, striae distinctly impressed, with fine and dense punctures; intervals moderately convex, with fine and moderately dense punctures concentrated along striae, glabrous, penultimate lateral interval with a few fine single and short setae; epipleural edge moderately strong, ending at strongly rounded external apical angle of elytra, epipleura densely setose, apical border narrowly membraneous, with a rim of short microtrichomes.

Ventral surface shiny, with coarse and dense punctures, glabrous except a minute seta in punctures. Metacoxa only laterally with a few robust longer setae. Abdominal sternites finely and densely punctate and minutely setose, each sternite with a distinct transverse row of coarse punctures each bearing a short, robust seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.4. Pygidium strongly convex and shiny, with coarse, dense punctures and a few fine, short setae on apical margin.

Legs slender; femora finely densely and coarsely punctate and glabrous, except for minute setae of punctures, with two longitudinal rows of setae; anterior margin of metafemur acute, without an adjacent continuously serrated line; ventral posterior margin weakly widened in apical half, completely strongly serrate, dorsal posterior margin also completely serrate. Metatibia slender and long, widest at apex, ratio width/length: 1/3.7, moderately carinate dorsally, with only one group of spines at 7/8 of metatibial length, basally with a few single spines in punctures; beside dorsal margin with a continuously serrated line until the group of spines convergent with dorsal margin, between serrated line and dorsal margin finely punctate; lateral face longitudinally convex, with sparse and coarse punctures bearing a minute seta; ventral margin finely serrated, with three fine and long, robust setae, of which the distal one is by far more distant from the others; medial face densely finely punctate, punctures with minute setae; apex interiorly near tarsal articulation shallowly concavely sinuate. Tarsomeres dorsally impunctate, ventrally with short, sparse setae. Metatarsomeres ventrally with a strongly serrated ridge and glabrous, laterally not carinate; first metatarsomere distinctly shorter than following two tarsomeres combined and little longer than dorsal tibial spur. Protibia moderately long, bidentate, protarsal claws symmetrical, basal tooth of inner claw simply but sharply truncate at apex.

Aedeagus: Fig. 11A–C . Habitus: Fig. 11D . Female unknown.

Variation. Length: 6.9–7.8 mm, length of elytra: 5.1–5.9 mm, width: 4.0– 4.6 mm.

Diagnosis. Amiserica venxianensis Ahrens, Fabrizi & Liu , new species differs from the other Amiserica species of the Amiserica guizhouensis grop by the shiny ventral surface and the symmetric, simple parameres which are not bilobate; furthermore, the phallobase has no narrow apical dorsomedian process.

Etymology. The new species is named after one its type locality, Venxian (adjective in nominative case).

Figures

FIGURE 11. A–D: Amiserica venxianensis Ahrens, Fabrizi & Liu, new species (holotype); E–H: A. linzhouensis Ahrens, Fabrizi & Liu, new species (holotype); I–L: A. gulinqin Ahrens, Fabrizi & Liu, new species (holotype). A, E, I: Aedeagus, left side lateral view; C, G, K: Aedeagus, right side lateral view; B, F, J: Parameres, dorsal view; D, H, L: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 18. Distribution of the species of the Amiserica venxiaensis group.