Maladera robustula Ahrens, Fabrizi & Liu, 2021

Fabrizi, Silvia, Liu, Wan-Gang, Bai, Ming, Yang, Xing-Ke & Ahrens, Dirk, 2021, A monograph of the genus Maladera Mulsant & Rey, 1871 of China (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 4922 (1), pp. 1-400 : 31-33

Maladera robustula Ahrens, Fabrizi & Liu , sp. n.

Figures 5 E–I, 86

Type material examined. Holotype: ♂ “ China: Hubei; Dahongshan 1700m, Shuizhou VI-2003 leg. Ying et al. / 722 Sericini : Asia spec.” ( ZFMK).

Description. Length: 10.2 mm, length of elytra: 7.3 mm, width: 5.8 mm. Body oblong-oval, dark reddish brown, antenna yellow, shiny, dorsal face nearly glabrous.

Labroclypeus wide and subtrapezoidal, widest at base, lateral margins weakly convex and convergent anteriorly, anterior angles strongly rounded, anterior margin moderately emarginate, margins moderately reflexed; lateral margin and ocular canthus produce an indistinct angle; surface weakly convex, coarsely, very densely punctate, with a few long setae anteriorly; frontoclypeal suture distinctly incised, weakly curved; smooth area anterior to eye convex, twice as wide as long; ocular canthus moderately long and wide (1/3 of ocular diameter), finely densely punctate, with two terminal setae. Frons shiny, with very dense and coarse punctures, and moderately dense, erect setae. Eyes small, ratio diameter/ interocular width: 0.5. Antenna with ten antennomeres; club with three antennomeres and straight, as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately transverse, widest at base, lateral margins weakly convex and convergent anteriorly, anterior angles distinctly produced and sharp, posterior angles blunt; anterior margin straight, with fine marginal line, base without marginal line; surface very finely and densely punctate, with minute setae in punctures being as long as puncture diameter, otherwise glabrous; anterior and lateral margin densely setose; hypomeron carinate, not produced ventrally. Scutellum wide, triangular, with fine, very dense punctures.

Elytra widest in posterior third, striae finely impressed, finely and densely punctate, odd intervals weakly convex, even ones flat, with fine, very dense punctures, with minute setae in punctures, penultimate lateral interval with a few fine setae; epipleural margin robust, ending at apical external angle of elytra, epipleura densely setose; apical border of elytra membraneous, with a very fine rim of microtrichomes (visible at ca 100x magnification).

Ventral surface dull, coarsely and densely punctate, metasternum including disc densely setose; metacoxa glabrous, with a few longer setae laterally. Abdominal sternites finely and densely punctate, punctures with minute setae, each sternite with a transverse row of punctures each bearing a fine seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.23. Pygidium dull, weakly convex, finely and densely punctate, without smooth midline, with dense short and numerous long and fine setae.

Legs moderately long and wide, shiny; femora with two longitudinal rows of setae, coarsely and moderately densely punctate. Anterior margin of metafemur acute, with adjacent continuous serrated line, anterior row of setae complete; posterior ventral margin smooth, moderately widened at ventral apex, dorsal posterior margin smooth, neither serrate, glabrous. Metatibia moderately long and wide, widest at apex, ratio of width/length: 1/2.8, sharply carinate dorsally, with two groups of spines, basal group shortly behind middle, apical group at three quarters of metatibial length, in basal half with a few short and robust single setae and a continuous serrated line beside entire dorsal margin; lateral face longitudinally convex, with dense coarse punctures, punctures setose; ventral margin finely serrate, with four equidistant robust setae; medial face smooth and glabrous; apex finely serrate, distinctly deeply emarginate interiorly near tarsal articulation. Tarsomeres dorsally impunctate, glabrous, neither laterally nor dorsally carinate, moderately setose ventrally; metatarsomeres with a strongly serrated ridge ventrally and a smooth subventral longitudinal carina; first metatarsomere distinctly longer than following tarsomere and as long as dorsal tibial spur. Protibia moderately long, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Fig. 5 E–H. Habitus: Fig. 5I . Female unknown.

Diagnosis. Maladera robustula Ahrens, Fabrizi & Liu , sp. n. differs from the very similar species M. opaciventris (Moser) in having the body larger, as well as by the shape of the parameres: the left paramere is convexly rounded apically and not pointed as in M. opaciventris .

Etymology. The name of the new species (adjective in the nominative singular) is derived from the Latin word robustulus (rather robust), with reference to its large size and the large left paramere.

Distribution. See map ( Fig. 86 ) and Table 1.

Figures

FIGURE 5. A–D: Maladera opaciventris (Moser, 1915) (China: Zhejiang: Mt. Longwangshan); E–I: M. robustula Ahrens, Fabrizi & Liu, sp. n. (holotype); J–N: M. wipfleri Ahrens, Fabrizi & Liu, sp. n. (holotype). A, E, J: aedeagus, left side lateral view; C, H, M: aedeagus, right side lateral view; B, F, G, K, L: parameres, dorsal view; D, H, N: habitus. Scale: 0.5 mm. Habitus not to scale.

FIGURE 86. Distribution of the subgenus Eumaladera: Maladera fencli sp. n., M. opaciventris (Moser, 1915), M. robustula sp. n., M. subrugata (Moser, 1926), Maladera wipfleri sp. n. (not precisely localized collection site indicated by a “?”).