Description Shell medium-sized, robust, fusiform (W/H 0.41, A/H 0.46), heavily sculptured, with stepped spire. Protoconch papilliform, light brown, of >2 smooth, slightly convex whorls. Teleoconch of about 8.5 distinctly shouldered whorls, giving spire a stepped appearance; suture deeply impressed. Early whorls with flattened profile below shoulder, expanding towards lower suture. Subsutural band discernible from second whorl, becoming progressively stronger on later whorls, separated from slightly convex whorl periphery by deeper groove. Sculpture of strong, raised, orthocline ribs, triangular in cross- section, 12 on last whorl. 13 on penultimate whorl, interspaces slightly wider than ribs. Ribs overridden by low, rounded, slightly undulating cords, separated by shallow grooves; early spire whorls with four subequal cords, including subsutural band consisting of a single cord. On later whorls, subsutural band slightly protruding, subdivided into 2 (penultimate whorl) or 3 (last whorl) closely set, weakly delimited, cords, followed by widened groove. Last whorl with five cords on periphery, followed by 3 cords on base becoming progressively narrowed, with wider interspaces. Microsculpture of very fine growth lines. Siphonal canal demarcated from shell base by strong gemmate cord, confluent with adapicalmost columellar fold, followed by four weakening, oblique. cords on moderately developed fasciole Aperture narrow, elongated, with undulating outer lip with five lirae deepened in aperture. Inner lip with four columellar folds, adapicalmost strongest, anterior quarter of lip reflected, producing shallow pseudo-umbilicus. Background color olive-green; crests of ribs, shell base and siphonal canal orange, white spiral band around mid-height of whorl Radula unknown. Etymology Latin amicum, (friendly, dear, loyal), referring to the warm orange-gamma colors of the shell Distribution Known from Vietnam to Vanuatu, at shallow subtidal depths. Remarks Vexillum amicum sp. nov. is close to Vecillum crocatum , but can be differentiated from the latter by a strong subsutural band, which on late whorls is often protruding, resulting in the stepped appearance of the spire. In V. crocatum, conversely, the adapical cord is weaker than the succeeding one, and therefore the shoulder is notably less pronounced. Furthermore, while both species are variable in color, the shells of V. amicum are often burnt orange or with shades of brown, unlike the predominately yellow/orange shells of V. crocatum. As our analysis demonstrated, Vexillum flavescens (Reeve, 1844) and Vexillum concinna (Reeve, 1844) are merely color forms of V. crocatum. Vexillum cumingii within this complex is a species with a more robust shell, an elongated spire, and irregular mottled white splashes across all whorls. Finally, Vexillum purpuratum (Reeve, 1845) has some similarities to V. amicum sp. nov. in that it has similar size and lacks the rough/prickly pustules, but its shells are more compressed , the axial ribs more robust, and it is distinguishable in bearing a broad dark purplish brown band on the shoulder.