Penion hiatulus is an extinct species of marine mollusc gastropod in the family Austrosiphonidae. Fossils of the species date to the Pliocene in New Zealand.
In the original description, Powell described the species as follows:
The holotype of the species has a height of and a diameter of .
The species was first described by A.W.B. Powell in 1947, using the name Verconella hiatula. The genus Verconella was synonymised with Penion in 1954, leading to the species' current accepted name. The holotype was collected in January 1927 by A. W. B. Powell, from the South Taranaki Bight coast between the Kai Iwi Stream and Okehu Stream in the Whanganui District, New Zealand, and is held by the Auckland War Memorial Museum.
This extinct marine species occurs in Pliocene (Opoitian stage) of New Zealand, dating to 5.33 million years before the present.