Trigonopterus costatulus Riedel

Riedel, Alexander & Narakusumo, Raden Pramesa, 2019, One hundred and three new species of Trigonopterus weevils from Sulawesi, ZooKeys 828, pp. 1-153 : 1

18. Trigonopterus costatulus Riedel sp. n.

Diagnostic description.

Holotype, male (Fig. 18a). Length 2.28 mm. Color of antennae and legs ferruginous; remainder dark ferruginous. Body subovate; in dorsal aspect and in profile with weak constriction between pronotum and elytron. Rostrum dorsally with median ridge and pair of submedian ridges; intervening furrows with sparse rows of suberect setae; epistome posteriorly with transverse, angulate ridge. Pronotum with weak subapical constriction; disk coarsely punctate-reticulate; each puncture with suberect, weakly spatulate scale. Elytra with striae deeply impressed, containing rows of punctures each with short, suberect scale; intervals costate, subglabrous; sutural interval raised, with additional row of punctures; apex produced ventrad. Metathoracic spiracle located on laterally projecting denticle. Femora edentate. Metafemur subapically with stridulatory patch. Mesotibia apically confluent with enlarged, curved uncus. Abdominal ventrites 1-2 medially deeply impressed, with dense coarse punctures; ventrite 5 medially with distinct subglabrous depression, laterally coarsely punctate. Penis (Fig. 18b) with sides of body weakly diverging; apex subangulate, sparsely setose; apodemes 1.6 × as long as body of penis; transfer apparatus complex; ductus ejaculatorius with apical part broken and missing. Intraspecific variation. Length 2.22-2.60 mm. Female rostrum slender, dorsally with ridges more rounded; epistome indistinct. Female elytral apex ventrally concave, with sutural interval in profile forming subangulate projection. Female abdominal ventrite 5 with shallow median depression, evenly coarsely punctate.

Material examined.

Holotype (MZB): ARC3075 (GenBank # MK260537), S-Sulawesi Prov., Tanah Toraja, Ponding, Baruppu, 02°48.010'S 119°47.560'E, 2199 m, sifted, 04-V-2013. Paratypes (ARC, MZB, SMNK): S-Sulawesi Prov., Tanah Toraja: 7 exx, ARC3073 (GenBank # MK260536), ARC3074 (GenBank # MK260535), same data as holotype; 6 exx, ARC3068 (EMBL # LN884956), ARC3069 (GenBank # MK260534), Ponding, Baruppu, 02°48.339'S 119°47.880'E, 2113 m, sifted, 04-V-2013; 15 exx, Ponding, Baruppu, 02°49.662'S 119°48.871'E, 2173 m, sifted, 05-V-2013; 23 exx, Ponding, Baruppu, 02°47.918'S 119°47.408'E, 2233 m, sifted, 04-V-2013; 4 exx, Tanah Toraja, Pulu Pulu, 2400 m, sifted, 15-16-VIII-1990.

Distribution.

S-Sulawesi Prov. (Tanah Toraja). Elevation 2100-2400 m.

Biology.

In leaf litter of montane forest.

Etymology.

This epithet is based on the diminutive form of the Latin adjective costatus, -a, -um (ribbed) and refers to the species´ small size and its elytral sculpture.

Notes.

Trigonopterus costatulus Riedel, sp. n. was coded as " Trigonopterus sp. 511".