Melixanthus similibimaculicollis Duan, Wang & Zhou, 2021

Duan, Wen-Yuan, Wang, Feng-Yan & Zhou, Hong-Zhang, 2021, Two new species of the genus Melixanthus Suffrian (Coleoptera, Chrysomelidae, Cryptocephalinae) from China, ZooKeys 1060, pp. 111-123 : 111

Melixanthus similibimaculicollis Duan, Wang & Zhou sp. nov.

Figures 1 , 2 , 6 , 7

Type locality.

China: Yunnan Province: Cheli.

Type material examined.

Holotype: male, China: Yunnan Province: Cheli, 9.III.1957, coll. Fuji Pu (IZ-CAS); Paratypes: China: Yunnan Province: 1 male, 50 km southwest of Mojiang, 30.III.1955, coll. Kryzhanowski (IZ-CAS); 1 female, Longling, 1600 m, 20.V.1955, coll. Kryzhanowski (IZ-CAS).

Measurements.

BL = 2.55-2.82 mm, BW = 1.57-1.73 mm, HL = 0.82 mm, HW = 0.85 mm, PL = 0.90 mm, PW = 1.62 mm, EL = 1.81 mm, AL = 0.91 mm, AW = 0.34 mm, SW = 0.39 mm.

Description.

Body (Fig. 6A, B ) elongate, almost cylindrical, rounded anteriorly. Head yellow, vertex with a darkish brown triangular marking; antennae (Fig. 6C ) with basal 5 segments yellowish brown, the rest brown; clypeus yellow; labrum yellowish brown; mandibles reddish brown. Pronotum yellow, and basal margin pitchy brown, forming 2 nearly round pitchy brown markings along anterior margin. Scutellum entirely black. Elytra pitchy black only in basal and apical parts, with a large yellow band in middle region, covering about 2/3 of whole elytron; sutural and lateral margins also pitchy black. Ventral surface yellowish brown.

Head with sparsely pubescence, without punctures, flattened in midline, and with longitudinal shallow groove on frons. Eyes kidney-shaped, deeply emarginated; antennal insertions about equally separated with superior eye-lobes. Clypeus trapeziform, anterior margin concave, without punctures. Antennae (Fig. 6C ) long and slightly thin, reaching 1/3 region of elytra; 1st segment clubbed; 2nd oblong, about 1/2 as long as 1st; 3rd-5th thin, about equal in length, longer than 2nd; 6 apical segments moderately thickened, about 1.7-2.0 times as long as wide, last segment pointed apically.

Pronotum (Fig. 6A, B ) 1.8 times as wide as long, moderately narrowed and rounded anteriorly; surface strongly convex, impunctate and shining. Scutellum triangular, nearly as long as wide, surface smooth, shining, apically elevated, observable in lateral view.

Elytra (Fig. 6A, B ) with humeri prominent and glabrous, widest slightly behind humerus, feebly truncated at apex. Disc with regular rows of coarse punctures; interspace of rows without any punctures; epipleura slightly obliquely placed and observable in lateral view.

Ventral side smooth, partly clothed with pubescence. Prosternum (Fig. 1C, D ) square, anterior margin nearly straight; basal margin slightly concave, and drawn out into a pair of small denticles. Mesosternum trapeziform, 1.5 times as wide as long. Metasternum with coarsely sporadic punctures in sutural region and with sparse pubescence. Pygidium flat, punctate and pubescent. Claws (Fig. 2C, D ) distinctly toothed, thickened basally.

Aedeagus (Figs 6D-F , 7A-C ) elongate, about 2.7 times as long as wide, clubbed. Anterior margin of median lobe nearly straight, middle part papillary protruding, strongly curved in lateral view; with several pubescence on each side of apex and upper lateral margins, punctate on apex of median lobe. Median orifice with middle sclerite bending inwards above surface. Upper part of median lobe with a pair of sclerotized prominence, exceeding the median lobe. Inner sac rather narrow, arrow-shaped. Tegmen Y-shaped, weakly sclerotized, almost translucent.

Female. Body more robust than male; spermatheca (Fig. 7D ) hook-shaped, bent at a right-angle halfway, slightly acute at apex. Duct weakly sclerotized, tightly coiled. Rectal sclerites absent in specimen studied.

Distribution.

China (Yunnan).

Etymology.

The specific epithet is derived from the Latin terms simili -, bi -, maculi - and collis, to indicate the new species near to M. bimaculicollis .

Diagnosis.

The new species is similar to M. bimaculicollis Baly, 1865, but can be distinguished from it by the smaller body size; head and scutellum without any punctures; slightly narrower pronotum; elytra with finer punctures, and only basal part punctures surrounded by dark ring; basal margin of prosternum (Fig. 1C, D ) drawn out into a pair of small sharp denticles. Melixanthus similibimaculicollis is also similar to M. menglaensis Duan, Wang & Zhou, sp. nov., but can be distinguished by the following characters: head without punctures; claws toothed (Fig. 2C, D ); and body size smaller.

Figures

Figure 1. Melixanthus prosternum A, B M. menglaensis Duan, Wang & Zhou, sp. nov. C, D M. similibimaculicollis Duan, Wang & Zhou, sp. nov. E, F M. bimaculicollis Baly, 1865.

Figure 2. Melixanthus claws A, B M. menglaensis Duan, Wang & Zhou, sp. nov. C, D M. similibimaculicollis Duan, Wang & Zhou, sp. nov. E, F M. bimaculicollis Baly, 1865. Scale bars: 0.1 mm.

Figure 6. Melixanthus similibimaculicollis Duan, Wang & Zhou, sp. nov. A habitus B lateral view of habitus C antennae D lateral view of aedeagus E ventral view of aedeagus F dorsal view of aedeagus. Scale bars: 0.5 mm (A, B), 0.2 mm (C-F).

Figure 7. Melixanthus similibimaculicollis Duan, Wang & Zhou, sp. nov. A dorsal view of aedeagus B ventral view of aedeagus C lateral view of aedeagus D spermatheca. Scale bars: 0.2 mm.