Plateros siniaevi Kazantsev sp.n.

Figs 54, 173–174.

MATERIAL: Holotype, ♂, S Vietnam, Bao Lok, 1500 m, 10– 20.XII.1992, V. Siniaev leg. (ICM); paratypes, 2 ♀♀, same label (ICM).

DESCRIPTION. Male. Dark brown to black; head, pronotum, scutellum and elytra testaceous (Fig. 54).

Vertex with conspicuous round impression behind antennal prominence and two approximate minute deep round excavations at its bottom. Eyes relatively large, interocular distance ca. 1.1 times shorter than eye diameter. Labrum small, transverse, almost truncate anteriorly. Palps slender; ultimate palpomeres slightly longer than wide, gradually narrowing distally, obliquely convex and flattened at apex. Antennal sockets separated by minute lamina. Antennae ramose; ramus of antennomere 3 ca. 1.1 times shorter than stem; antennomere 3 ca. 3 times longer than antennomere 2 and ca. 1.3 times shorter than antennomere 4; antennomeres 3–11 with long erect pubescence (Fig. 54).

Pronotum transverse, ca. 1.5 times wider than long, trapezoidal, with slightly concave sides, almost straight basally and strongly semi-circularly produced anteriorly, with small acute, somewhat protruding laterally posterior and rounded anterior angles. Scutellum transverse, parallel-sided, triangularly incised at apex (Fig. 54).

Elytra long, ca. 3.3 times longer than wide at humeri, slightly widening distally; with four prominent, almost equally developed primary costae, noticeably stouter than secondary ones; interstices with even rows of regular subquadrate cells; pubescence dense, short and decumbent (Fig. 54).

Legs slender; femoris and tibiae narrow, subequal in length (Fig. 54).

Aedeagus asymmetrical, with narrow phallobase and contiguous phallobasal lateral plates; median lobe spiral, with proximally directed first coil and narrow acute apex (Figs 173–174).

Female. Similar to male, but eyes distinctly smaller and antennae only slightly dentate.

Length: 7.3–8.8 mm. Width (humerally): 1.7–2.0 mm.

ETYMOLOGY. The new species is named after Viktor Siniaev (Moscow) who collected its type series.

DIAGNOSIS. Plateros siniaevi sp.n. may be distinguished from the somewhat similar-looking P. planatus by the ramose antennae (Fig. 54) and spiral median lobe of its aedeagus (Figs 173–174), being different from other Plateros species with spiral median lobe of the aedeagus by the proximally directed first coil and its narrow acute apex.

DISTRIBUTION. Southern Vietnam.