Maladera enigma 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 : 57

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

Figures 10 I–L, 91

Type material examined. Holotype: ♂ “[ China] Jiangxi, Mt. Jinggangshan Songmuping , under the stone of the stream, 2011-V-27, leg. Song Keqing / LW-1160” ( ISAZ).

Description. Length: 9.4 mm, length of elytra: 7.2 mm, width: 5.2 mm. Body oval, dark brown, antenna yellow, dorsal surface dull, labroclypeus, tarsomeres, and tibiae shiny, glabrous.

Labroclypeus wide, trapezoidal, lateral margins straight and convergent, producing with ocular canthus an indistinct angle, anterior angles strongly rounded, anterior margin weakly emarginate medially, margins weakly reflexed; surface flat, base narrowly dull, finely and densely punctate, with numerous erect setae in slightly larger punctures; frontoclypeal suture finely incised, bluntly angled medially; smooth area in front of eyes 1.5 times as wide as long; ocular canthus moderately wide and long (equals 1/3 of ocular width), finely and sparsely punctate, without terminal seta. Frons with superficial, moderately dense punctures, with a few single setae beside eyes and behind frontoclypeal suture. Antenna with ten antennomeres, club with three antennomeres, as long as remaining antennomeres combined. Eyes small, ratio diameter/ interocular width: 0.55. Mentum convexly elevated and flattened anteriorly.

Pronotum widest at base, lateral margins moderately but evenly convex and convergent anteriorly, anterior angles sharp and distinctly produced, posterior angles blunt; anterior margin nearly straight, with a fine marginal line being widely interrupted medially; basal margin without marginal line; surface finely and moderately densely punctate, setae of lateral and anterior margin fine but sparse, punctures with microscopic setae only. Hypomeron carinate, not ventrally produced. Scutellum wide, triangular, punctation as on pronotum.

Elytra widest behind middle, striae distinctly impressed, finely punctate, intervals weakly convex, finely and densely punctate, on odd intervals punctures concentrated along striae and with a few single short setae; epipleural margin robust, ending at strongly rounded external apical angle of elytra, sparsely setose; apex of elytra with a very fine membraneous rim of short microtrichomes.

Ventral face coarsely and densely punctate, nearly glabrous, only metasternal plate and lateral metacoxa with a few robust setae. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/ 1.67. Abdominal sternites finely and moderately densely punctate, each with a row of coarse punctures bearing each a robust seta. Pygidium weakly convex, finely and densely punctate, lateral and apical margins with very short setae.

Legs moderately wide; femora finely and sparsely punctate, with two longitudinal rows of setae. Metafemur dull, anterior margin acute, without adjacent serrated line; posterior ventral margin almost straight, strongly widened in apical half, as dorsal posterior margin not serrated, glabrous. Metatibia long and moderately wide, ratio width/ length: 1/ 3.1, sharply carinate dorsally, with two groups of spines, basal one at middle, apical one at four fifths of metatibial length, basally with a few robust and short spines; lateral face weakly longitudinally convex, finely and sparsely punctate on sides and basal half; medial face impunctate and glabrous, apex concavely emarginate interiorly near tarsal articulation. Tarsomeres impunctate dorsally, with dense, fine setae ventrally; metatarsomeres ventrally glabrous, with a strongly serrated carina, subventrally with a second, smooth longitudinal carina; first metatarsomere little shorter than following two tarsomeres combined, little longer than dorsal tibial spur. Protibia moderately long, bidentate, without blunt external extension at middle; anterior claws symmetric, interior tarsal claws sharply pointed.

Aedeagus: Fig. 10 I–K. Habitus: 10L. Female unknown.

Diagnosis. Maladera enigma Ahrens, Fabrizi & Liu , sp. n. resembles other species of Omaladera in the shape of phallobase and and parameres, however, it differs in characteristics of labroclypeus (dull at base, not carinate medially).

Etymology. The name of the new species is derived from Greek word, enigma (Engl. enigma), with reference on to uncertain systematic position of the species (noun in apposition).

Distribution. See map ( Fig. 91 ) and Table 1.

Figures

FIGURE 10. A–D: Maladera lignicolor (Fairmaire, 1887) (holotype Autoserica tenebrosa Frey, 1972); E–H: M. orientalis (Motschulsky, 1858) (lectotype); I–L: M. enigma Ahrens, Fabrizi & Liu, sp. n. (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. Scale: 0.5 mm. Habitus not to scale.

FIGURE 91. Distribution of the subgenus Omaladera: Maladera enigma sp. n., M. formosae (Brenske, 1898), M fusca (Frey, 1972), M. guangdongana sp. n., M. hongkongica (Brenske, 1898).