As Vexillum (Protoelongata); subsequently raised to genus according to WoRMS (2019 version).
Herrmann, M.; Stossier, G.; Salisbury, R. A. (2014). A new subgenus including three new species of the genus Vexillum (Gastropoda: Costellariidae) from the central Indo-Pacific with remarks on Vexillum (Pusia) semicostatum (Anton, 1838). <em>Contributions to Natural History (Bern).</em> 24: 1-55.