An initiative of Earthwatch Institute

  1. Ribbed1_keith_davey-cropped Up to 50mm by K Davey
  2. Ribbed2_elvira_poloczanska-cropped Grey to off-white in colour by E. Poloczanska

Ribbed Top Shell

Austrocochlea constricta


  • Ribbed top shells are a medium sized marine snail (mollusc)
  • They are grey or off-white in colour, with 5 or 6 distinctive ridges spiralling up towards a sharp tip (apex).
  • Size:  25-50mm

What to Observe

Search area for 30 minutes and record under the following categories-

  • 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

ClimateWatch Science Advisor

Ribbed top shells, 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.

When To Look

Throughout the year

Where To Look

  • Common on rocky shores, from high to mid tide levels. Usually found in rock pools and wet areas.
  • Albany WA, SA, TAS, VIC up to Coffs Harbour NSW.
 Ribbed Top Shell distribution map - GBIF

Ribbed Top Shell distribution map - GBIF



Davey, K. (1998). A Photographic Guide to Seashore Life of Australia. New Holland Publishers Australia Pty Ltd.


Edger, GJ. (2008). Australian Marine Life. The Plants and Animals of Temperate Waters [2nd Ed]. New Holland Publishers Australia Pty Ltd.


  1. Search Species

  1. What Else?

    The ribbed top shell can look similar to the Zebra top shells (Austrocochlea porcata), which can also have faint ribs wrapping around the shell. However the zebra top shells can be distinguished by their distinctive black and white striped pattern on their shells do not follow the ribs but cross them vertically. 

  1. Did You Know?

    Ribbed top shells can also found on estuarine mud flats and in seagrass meadows.