Euthrio boavistensis is characterized by a small, moderately thin but solid shell; a broad shape with moderately short spire resulting in a semi-oval shell; the conical spire with laterally flattened whorls; in combination with a weak sculpture of fine spiral threads. The colour is varying from pale yellow to dark chocolate; with large, irregular shaped yellowish to dark brown dots arranged in thre broad spiral bands, separated by paler bands; occasionally small white spots arranged in narrow spiral bands present along the last whorl. Both the apex and the siphonal canal are white, while the aperture is purple.

We regard Euthria sp. discussed by Rolan (1987:299-300, fig. 8) conspecific to E. boavistensis, the absence of spiral sculpture on the shell and the paler colour of the animal falling within the infraspecific variability of the species. Euthria rolani differs from f. boavistensis in its much broader shape with shorter, constricted, base; the smoother whorls and the presence of a small fasciole along the siphonal canal. Euthrio pulicaria differs from E. boavistensis in its usually broader shape with a shorter siphonal canal, its inflated base; its subsutural concavity and the larger adult size.

Cape Verde. In shallow water (1-6 m) at Boavista and the Joao VicenteValente Bank. The species prefers sandy bottom with stones but is also found on more muddy bottoms when stones and rocks are present, at the base of rocks.