Euthria taeniopsoides is characterized by the small shell, having a high spire and the fine but sharp spiral cords especially along the base. The colour is usually vivid, with pale spots especially along mid-whorl; usually in combination with fine, dark, interrupted spiral lines. The colour shows a strong degree of variability which is geographically or ecologically indicated (ecophenotypes) with little or without polymorphism (variability within a population). One can recognize the three populations around Sal Island: reddish-brown shells at the northwest coast (type locality), almost black shells on the east coast and a population of pale yellowish shells on the central-east coast, as already recorded by Fraussen et al. (2011: 86-87, fig. 7-10). The number of spiral cords and axial ribs is quite variable in this species. The spiral cords on the last whorl may vary from 12 or 13 (in the holotype) to up to 20 (in new material, FS). Until now the maximum amount of observed spiral cords differs considerably between the orange-red form (up to 15 spiral cords on the last whorl) and the yellow form (up to 20 spiral cords).

Euthria calderoni differs from E. taeniopsoides in having fewer protoconch whorls (1,5 instead of 2), broader spiral cords, especially along the base and in having fewer axial ribs on the upper spire whorls. The colour of E. calderoni is usually much darker (however dark forms of E. taeniopsoides exist also, at the east coast of Sal).
Euthria emilioi differs from E. taeniopsoides in having fewer protoconch whorls (1,5 instead of 2) in combination with a similar or slightly larger diameter (1.1 mm instead of 1.0 mm); a much weaker subsutural concavity and much broader spiral cords especially along the base. The colour of E. emilioi is uni-form (however usually also vivid) without pattern.

Cape Verde. In shallow water (0,25 to 2 m) off Sal Island. The species prefers living under rocks in tide pools at 0,25 to 0,5 m deep and under rocks and rock slabs in gravel and sand at 34 to 2 m deep.