Powellisetia unicarinata
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| Powellisetia unicarinata | |
|---|---|
_(AM_MA70544).jpg) | |
| Holotype of Powellisetia unicarinata from Auckland War Memorial Museum | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Family: | Rissoidae |
| Genus: | Powellisetia |
| Species: | P. unicarinata |
| Binomial name | |
| Powellisetia unicarinata (Powell, 1930) | |
| Synonyms[1] | |
| |
Powellisetia unicarinata is a species of marine gastropod mollusc in the family Rissoidae.[1] First described by Powell in 1930 as Notosetia unicarinata, it is endemic to the waters of New Zealand.
Powellisetia bilirata has a minute, roughly ovate shell with a single strong spiral ridge. It is coloured dull-white,[2] has a strongly carinated shoulder, and weak angulation found in the lower body whorl.[3] The species measures 1.19 mm (0.047 in), by 0.59 mm (0.023 in).[4] The species' shell has a reasonably tall spire and a strongly tilted protoconch, and shell width is the major factor that varies between individuals in the species.[5]
The species is similar in appearance to Powellisetia porcellanoides, but can be distinguished by its angled carnate shoulder.[5]