"Resembling Boreotrophon, with long coronating spines, but also possessing successive canals that are so curved that their projecting portions, recurving from the siphonal fasciole, form a whorl of hollow, split spines, diverging from a deep umbilical [pseudoumbilical] pit, as in some murices."

Actinotrophon species differ from species of Poirieria s. s. by their smaller size, more strongly shouldered last teleoconch whorl, higher spire, relatively shorter siphonal canal, smaller aperture, and absence of any additional spines below the peripheral spines on last whorl. P. (P.) kopua Dell, 1956 is the only species of Poirieria s. s. lacking additional spines on the last teleoconch whorl. However, all other features are typical for Poirieria s. s., which is apparently restricted to the New Zealand region (MARSHALL & HOUART, 1995).
P. (A.) fragilis was described from New Caledonia. Other specimens have been recorded since its description, and extend considerably the geographical distribution.