Penion haweraensis is an extinct species of sea snail, a marine gastropod mollusc in the family Austrosiphonidae. Fossils of the species date to late Pliocene strata of the Tangahoe Formation in New Zealand.
In the original description, Powell described the species as follows:
The holotype of the species has an estimated height of , and a diameter of . It can be distinguished from P. mandarinus due to having nine primary cords and one thread per interspace on the penultimate whorl, compared to 10-12 primary spiral cords and between 2-6 spiral threads per interspace in P. mandarinus.
The species was first described by A. W. B. Powell in 1931, who named the species Austrosipho (Verconella) haweraensis. As Austrosipho was synonymised with Penion in 1930, the current accepted name for the species is Penion haweraensis. Powell believed that the species was ancestral to P. mandarinus, due to similarities in form and size, but differentiated the species based on sculpture detail differences. In 1973, A. G. Beu synonymised Aeneator contractus with the species, finding that A. contractus was a juvenile form of the species.
The holotype was collected in January 1931 from near the mouth of Waihi Stream near HÃÂwera, Taranaki, and is held in the collections of Auckland War Memorial Museum.
This extinct marine species occurs in late Pliocene (Waipipian) strata of the Tangahoe Formation, primarily associated with the Taranaki and Manawatà «âÂÂWhanganui regions of New Zealand. Fossils of the species have been found near HÃÂwera, South Taranaki, Martinborough in the South Wairarapa District, and near Masterton in the Masterton District.