Penion cuvierianus is a species of very large predatory sea snail or whelk, commonly called the flaring penion, a marine gastropod mollusc in the family Austrosiphonidae.

[1] Penion cuvierianus is a very large species of siphon whelk.

[2][3] The taxonomic name is a reference to the type locality of Cuvier Island.

[2] The species has an abundant fossil record in the North Island of New Zealand.

[5] The species occurs in the subtidal zone between depths of 20 and 200 metres.