Stiracolpus symmetricus, common name : the small turret, is a species of sea snail, a marine gastropod mollusk in the family Turritellidae.
The shell is elongate and turreted, with rounded whorls and deep sutures. Sculpture consists of three equal and evenly spaced spiral ribs. The aperture is roundish. The shell is white in colour. Hutton reported a shell length of about and a breadth of , with a spire angle of about 23ð.
This marine species is endemic to New Zealand. The type locality is Stewart Island.
Species of Stiracolpus typically live on sandy or muddy substrates in shallow subtidal environments on the continental shelf.
Stiracolpus is a genus of turreted marine gastropods endemic to New Zealand. Species in this genus are characterised by high-spired shells with strong spiral sculpture and inhabit soft-sediment marine environments. The genus has an extensive fossil record in New Zealand from the Neogene to Recent.
Fossils attributed to Stiracolpus symmetricus are common in Pleistocene marine deposits throughout New Zealand. Several fossil forms were described as distinct species but are now regarded as synonyms.