Brachytrycherus bipunctatus Chang & Bi sp. nov. Figs 1, 2, 3, 4

Type material.

Holotype (Fig. 1), male, Hainan, Fanjia Forest Reserve, 196 m, 19°16.806'N, 109°40.494'E, 17. IV.2016, Xing-Long Bai leg. (MHBU). Paratypes (Fig. 2), 1 female, Hainan, Qiongzhong, Shifangzhen, 22.II.2019, Guo-Dong Ren leg. (BJMNH); 1 female, Hainan, Dongfang, Mihouling, 11.VI.2008, Yi-Bin Ba & Jun-Tong Lang leg. (MHBU); 2 females, Hainan, Yinggeling. Nankai Township, Fangyuan Village, 21.VII.2013, Bo Cai leg. (CCLX); 1 female, Yunnan, Xishuangbanna, Mengla County, Mengla Town, Bubang Village, H: 680 m, 21°36'6"N, 101°35'9"E, Jian-Yue Qiu & Hao Xu leg. (CCLX) (Fig. 2).

Etymology.

The specific name is derived from the two apical elytral maculae.

Diagnosis.

Brachytrycherus bipunctatus can be distinctly separated from all congeners by having two distant spots on the elytral base.

Description.

Length 7.6-8.2 mm, width 4.1-4.2 mm. Body oval, approximately 2.0 times as long as wide; moderately convex; shiny. Colour black with three yellow maculae on each elytron.

Head. Antenna (Fig. 3A) rather stout, nearly 1/2 body length, with antennomeres 1-8 longer than wide; scape approximately 4.0 times as long as pedicel; antennomere 3 as long as 4 and 5 combined; antennomeres 4-6 nearly length equal; antennomere 6 longer than 7 and antennomere 7 as long as 8; club composed of three antennomeres, moderately broad, weakly flat, loose. Maxilla with terminal palpomere elongated, almost 1.5 times as long as palpomere 3, slightly tapering anteriorly, truncate apically.

Thorax. Pronotum (Fig. 3B) 1.5-1.7 mm long, 2.7-3.1 mm wide; widest near 1/2 of pronotal length; coarsely and densely punctate; anterior and lateral margins moderately narrowly bordered; anterior edge with rather large stridulatory membrane; sides weakly undulate; front angles produced anteriorly, blunt round; disc weakly convex, two round raised area laterally; transverse wrinkle laterally; median furrow shallow, two small round pits laterally; lateral sulci linear, groove, deep, extending to basal 1/3 length of pronotum; basal sulcus nearly straight, deep. Prosternal process (Fig. 3C) not extending beyond coxae; very narrowly separates procoxae, sides weakly curved outwardly, rounded apically in male; in female rather narrowly, sides nearly straight, weakly truncate apically. Mesoventral process (Fig. 3D) transverse, lateral margins distinctly widening apically in male; in female lateral margins nearly parallel; posterior margin nearly straight.

Elytra (Fig. 3F) 5.9-6.2 mm long, 3.6-3.9 times as long as and 1.4-1.5 times as wide as pronotum; sides curved, widest near 1/2 length of elytron; densely and coarsely punctate; humeri rather prominent. Each elytron with three orange-yellow maculae. Anterior two elytral maculae nearly oval or round, located behind humeri, size subequal, transverse arrangement, spacing between them subequal diameter of one macula. Posterior macula cloud-form, transverse, outer sides far from elytral lateral margin, inner margin of macula far from elytral suture. Protibia (Fig. 3E) in male with concavity on inner edge of apical 1/4 distinctly, in female without concavity; meso- and metatibiae simple. Hind wing (Fig. 3H) normal.

Ventrite V (Fig. 3G) with lateral margins abruptly converging posteriorly, three or four pairs of longitudinal short wrinkles laterally; posterior margin weakly curved medially in male; in female ventrite V lateral margins gently converging posteriorly, without longitudinal wrinkles; posterior margin bluntly round medially. Male genital segment (Fig. 3I) with paired apophyses fused along nearly half of its length apically; dorsal plate undivided; additional, internal, V-shaped sclerite present.

Aedeagus (Fig. 3 J–K) rather long, heavily sclerotized, straight. Median lobe branched apically; branch long, in apical view longitudinal Z-shaped; truncate apically. Tegmen placed basally, comparatively large, ring-shaped, parameres rectangle, fused with tegmen.

Biology and ecology.

The holotype was hand collected by simple searching, as it is active under the fallen decayed wood in the day (Fig. 4).