Maladera exigua ( Brenske, 1894 )

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 : 341-343

Maladera exigua ( Brenske, 1894)

Figure 82 D–F

Serica exigua Brenske, 1894: 9 , 37; Ahrens 2006b: 245; 2007b: 36; Autoserica exigua: Brenske 1897: 406 .

Type material examined. Lectotype (here designated): ♀ “ Coll. R. I. Sc. N. B. Chine / Schang-hai/ Coll. J. Thomson/ S. exigua type. Brsk./ Type” ( ISNB) . Paralectotype (here designated): ♀ “ Coll. R. I. Sc. N. B. Chine / Schanghai / Coll. J. Thomson / S. exigua typ. Brsk./ Type” ( ISNB) .

Description. Length: 7.6 mm, length of elytra: 5.4 mm, width: 4.6 mm. Body oval, dark brown, antennal club yellow, dorsal surface dull, labroclypeus weakly shiny, except a few setae on head dorsal surface glabrous.

Labroclypeus narrow, trapezoidal, lateral margins straight and moderately convergent, producing with the ocular canthus a blunt angle, anterior angles convex, anterior margin straight and strongly reflexed, lateral margin moderately reflexed; surface flat, weakly shiny, coarsely and very densely punctate, punctures fusing rugosely with each other, with a few short setae anteriorly; frontoclypeal suture finely incised, moderately curved; ocular canthus moderately wide and long (equals 1/3 of ocular width), finely and densely punctate, with a short terminal seta. Frons dull, with fine, dense punctures in anterior half, posteriorly sparsely punctate, with a few single setae beside eyes and on disc. Antenna with ten antennomeres, club with three antennomeres, 0.8 times as long as remaining antennomeres combined. Eyes moderately large, ratio diameter/ interocular width: 0.55. Mentum convexly elevated and flattened anteriorly.

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

Elytra widest at middle, striae finely impressed, finely punctate, even intervals flat, odd intervals weakly convex, finely and densely punctate, punctures concentrated along striae, odd intervals with a few short setae, otherwise glabrous except minute setae in punctures; 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. Metacoxa at apical margin with a fine rim of dense microsetae. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/ 1.75. Abdominen in both syntype specimens lacking.

Legs short and wide; femora finely and sparsely punctate, with two longitudinal rows of setae. Metafemur shiny, anterior margin acute, without adjacent serrated line, anterior row of setae complete; posterior ventral margin, strongly widened in apical half, ventrally and dorsally not serrated, glabrous. Metatibia moderately long and wide, ratio width/ length: 1/ 2.78, sharply carinate dorsally, with two groups of spines, basal one shortly before middle, apical one at three quarters of metatibial length, basally with a few robust and short setae, with a short serrated line in basal third; lateral face weakly longitudinally convex, finely and moderately densely punctate, along middle impunctate; ventral margin serrate with four equidistant spines; medial face impunctate, apex concavely emarginate interiorly near tarsal articulation. Tarsomeres impunctate dorsally, with moderately dense, fine setae ventrally; metatarsomeres ventrally with a strongly serrated carina, subventrally with a second, smooth longitudinal carina, glabrous; first metatarsomere slightly shorter than following two tarsomeres and as long as dorsal tibial spur. Protibia moderately long, bidentate; anterior claws symmetric, interior tarsal claws sharply pointed.

Head. Fig. 82D . Habitus: Fig. 82E, F . Male unknown.

Remarks. Only two female syntypes are known. So far, the specimens could not be matched with any of the known Chinese Sericini species. There is an additional female in the ZMHB (“Chusan Col. … (not readable)”), which is likely M. orientalis (Motschulsky) , however, it differs in morphology from the syntypes.

Figures

FIGURE 82. A–C: Maladera flammea (Brenske, 1898) (lectotype); D–F: M. exigua (Brenske, 1894) (lectotype); G–I: M. harmonica (Brenske, 1897) (lectotype). A, D, G: head, dorsal view; B, E, H: body, lateral view; C, F, I: habitus, dorsal view.