Holotype, male (Fig. 3a). Length 3.47 mm. Color of legs and head ferruginous, transverse band of elytra polished black, remainder with greenish coppery lustre. Body elongate; in dorsal aspect with marked constriction between pronotum and elytron; in profile dorsally flat. Rostrum with median and pair of submedian ridges; intervening furrows each with row of punctures and suberect piliform scales; epistome simple. Pronotum anterolaterally markedly projecting, rounded; with subapical constriction; disk densely punctate; punctures partly elongate and / or arranged in confluent rows forming rhombus-like pattern near midline; each puncture containing piliform white scale; medially with glabrous costa. Elytral intervals bearing each one row of course punctures flanked by glabrous ridges; striae hard to distinguish from secondary rows of punctures; punctures containing long, recumbent, cream-colored scales; at middle with transverse subglabrous band; interval 7 swollen subapically, forming lateral edge; apex subtruncate, sutural interval not protruding. Femora edentate; anteroventral ridge indistinct. Metafemur subapically with stridulatory patch. Dorsal edge of tibiae subbasally with angulation extended as acute tooth. Abdominal ventrite 5 with shallow concave pit, basally and laterally with long suberect scales. Penis (Fig. 3b) with body short, sides subparallel; apex broadly rounded; transfer apparatus complex, rotated to the left; apodemes 3.0 × as long as body; ductus ejaculatorius without bulbus. Intraspecific variation. Length 2.97–3.47 mm. Females more slender than males. Female rostrum with median and pair of submedian glabrous costae. Female elytra with lateral contour convex, widest near middle; male elytra widest between humeri; elytral sculpture of females less distinct, longitudinal ridges weak or absent, transverse band near middle indistinct, sparsely punctate. Female abdominal ventrite 5 flat.

Holotype (MZB): ARC2326 (EMBL # LM655779), East Java Prov., Banyuwangi Reg., Alas Purwo N.P., Pancur, sample 3, S08°41.533', E114°22.593', 25 m, 09-IV-2011. Paratypes (MZB, SMNK): E-Java Prov., Banyuwangi Reg., Alas Purwo N.P.: 6 exx, ARC2323 (EMBL # LM655776), ARC2324 (EMBL # LM655777), ARC2325 (EMBL # LM655778), Triangulasi, sample 1, S08°39.744', E114°21.976', 25 m, 09-IV-2011; 1 ex, ARC2327 (EMBL # LM655780) same data as holotype; 1 ex, Triangulasi, sample 4, S08°39.335', E114°21.772', 25 m, 10-IV-2011; 3 exx, Triangulasi, sample 5, S08°39.426', E114°21.890', 25 m, 10-IV-2011; 1 ex, Triangulasi, sample 7, S08°39.373', E114°21.842', 25 m, 10-IV-2011; 1 ex, Triangulasi, sample 8, S08°39.559', E114°21.823', 25 m, 10-IV-2011.

E-Java Prov. (Alas Purwo N.P.). Elevation: 25 m.

This epithet is based on the type locality, Alas Purwo National Park.

Trigonopterus alaspurwensis Riedel, sp. n. was coded as “Trigonopterus sp. 345” by Tänzler et al. (2014).