Ribbed Top Shell Harry Rose/Flickr

Ribbed Top Shell

A medium-sized marine snail (mollusc). They are grey or off-white in colour, with 5 - 6 distinctive ridges spiralling up towards a sharp tip (apex).


25 - 50 mm

Field Guide

Improve your identification skills. Download your Ribbed Top Shell guide here!

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What to Observe

Search area for 30 minutes and record the following:

  • Abundant: found easily with little searching

  • Frequent: found with minimal searching

  • Rare: only 1 or 2 individuals found with intensive searching

  • Not found: not present during search

Climate Adaptations

Black Nerites, like all marine snails (molluscs), are under increasing stress due to ocean acidification which can weaken their calcium carbonate shells and reduce body condition. This makes them more prone to disease, predation and low reproduction. Increasing water temperature as a result of climate change will likely affect their abundance and cause a southward shift in their distribution.

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When and Where

When To Look

  • Throughout the year

Where To Look

  • Albany in Western Australia, South Australia, Tasmania, Victoria up to Coffs Harbour in NSW
  • Common on rocky shores, from high to mid tide levels
  • Usually found in rock pools and wet areas
  • Also on estuarine mud flats and in seagrass meadows
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What Else?

Similar Species

Zebra Top Shell (Austrocochlea porcata) can also have faint ribs wrapping around the shell but can be distinguished by the black and white striped pattern on their shells that cross them vertically.