Holotype. China – Sichuan Prov. • ♂; glued on a card with labels as follows: “China: Sichuan, Wenchuan County, Zhenghegou; alt. 1456–1615 m; 15 May 2015; Ming-Xia Guo leg; SNCA1111.” “Holotype / Apateticaangusticollis / Chang, Schillhammer & Tang” [red label]; SHNU. Paratypes. China – Sichuan Prov. • 1♀, SNCA1114; same data as for holotype; NMW • 2♀♀, SNCA1112, SNCA1113; Dayi County, Xiling Snow Mt.; 30°38'60"N, 103°10'99"E; alt. 1250 m; 31 Jul 2021; Zhao & Cai leg.; SHNU.

Measurements: BL: 7.6–7.9 mm, FL: 7.0–7.3 mm. HW: 1.52–1.76 mm, PW: 2.99–3.38 mm, EW: 3.19–3.68 mm, AL: 4.07–4.12 mm, PL: 1.81–2.16 mm, EL: 3.99–4.26 mm.

Body (Fig. 2A, B) blackish, lateral margins of pronotum broadly dark reddish-brown; elytra with metallic-greenish hue; antennae, mouth parts and legs dark reddish-brown, femora becoming darker brown distally.

Head transverse; anterior portion with flat elevation between anterior margin and vertex, sides of elevation glossy; in postero-median portion with a cluster of numerous macropunctures; frons glossy; punctation of portions near inner margin of eye very dense with somewhat elongated punctural grooves. Antennae very long and slender; antennomere 4 approximately 2.5 times as long as broad, 5 three times as long as broad, and 10 approximately twice as long as broad.

Pronotum approximately 1.6 times as broad as long and 2.0 times as broad as head, broadest in posterior third; anterior margin narrower than head; lateral margins broadly explanate, gradually becoming narrower in anterior half, each with several marginal punctures; disc moderately elevated; punctation of disc coarse, dense laterally and sparser in middle; postero-median portions of disc with irregular impunctate patches.

Elytra approximately 2.1–2.2 times as long as pronotum; each elytron with nine moderately coarsely punctate striae; intervals flat with micropunctation; lateral apical angles of elytra obtuse. Scutellum weakly transverse. Legs very long and slender.

Abdomen with microsculpture on tergites VI–VIII.

Male. Tergite VIII convex, wedge-shaped; aedeagus (Fig. 2C–F) 1.8 mm long; median lobe robust, gradually tapering apicad, with apex moderately obtuse in ventral view; parameres moderately long and slender, apically tapered, and curved ventrad.

Female. Tergite VIII (Fig. 2G) relatively flat, apically rounded.

China (Sichuan).

The new species can be recognized among all known congeners with metallic elytra by the combination of the following characters: antennae and most of the legs reddish brown, pronotum with anterior margin narrower than head, and elytra with obtuse lateral apical angles.

The specific epithet is an adjective composed of the Latin adjective angustus (narrow) and the Latin noun collum (the neck). It alludes to the narrow anterior margin of the pronotum.