Holotype, male (Fig. 25a). Length 3.80 mm. Color of tarsi, tibiae and antennae ferruginous, remainder black. Body elongate; in dorsal aspect with marked constriction between pronotum and elytron; in profile dorsally evenly convex. Rostrum with median carina terminating on forehead and pair of submedian ridges; intervening furrows each with row of erect piliform scales; epistome with transverse, angulate ridge. Pronotum anterolaterally projecting, rounded; with subapical constriction; disk densely punctate, interspaces subglabrous; each puncture containing recumbent seta; disk with pair of submedian, shallow impressions. Elytra with striae weakly impressed, partly indistinct; intervals flat; punctation confused, more dense towards base, near basal margin punctures partly confluent; each puncture containing small recumbent seta; interspaces microreticulate; interval 7 swollen subapically, laterally weakly projecting; sutural interval at apex markedly swollen, forming pair of rounded apical protrusions. Anteroventral ridge of femora forming blunt tooth. Metafemur subapically with stridulatory patch. Abdominal ventrite 5 with broad impression, densely punctate, setose with erect setae. Penis (Fig. 25b) with sides of body subparallel; apex broadly rounded; transfer apparatus distinct, compact; apodemes 1.6 × as long as body; ductus ejaculatorius without bulbus. Intraspecific variation. Length 2.94–3.80 mm. Integument of males dull, microreticulate; females with punctures sparser and smaller, interspaces polished. Female rostrum dorsally with glabrous median costa bordered by submedian and sublateral pairs of furrows; epistome simple. Female elytra with lateral contour evenly convex to apex; male elytra with lateral contour at humeri subangulate, in straight line to apex. Female abdominal ventrite 5 flat.

Holotype (MZB): ARC0211 (EMBL # LM655433), West Java Prov., Mt. Halimun N.P., Citalahab, sample 2, S06°44.503', E106°31.550', 1200 m, 12-IX-2005. Paratypes (ARC, MZB, SMNK): W-Java Prov., Mt. Halimun N.P.: 3 exx, ARC0101, W-Java Prov., Mt. Halimun N.P., Citalahab, S06°44.503', E106°31.550', 1150 m, 20-21-IX-2004; 10 exx, ARC0212 (EMBL # LM655434), ARC0213 (EMBL # LM655435), same data as holotype; 1 ex, Citalahab, sample 1, S06°44.423', E106°31.738', 1100 m, 12-IX-2005; 2 exx, ARC0170, N Ciptarasa, sample 3, S06°49.867', E106°30.085', 1100 m, 19-IX-2005; 2 exx, ARC0216 (EMBL # LM655438), ARC0217 (EMBL # LM655439), Panguyangan, Mt. Talaga, ca.1000 m, 17-IX-2005.

W-Java Prov. (Mt. Halimun N.P.). Elevation: 1000–1200 m.

This epithet is a combination of the prefix di- (two, double) and the adjective derived from the Greek morphe (gestalt).

Trigonopterus dimorphus Riedel, sp. n. was coded as “Trigonopterus sp. 293”.