This crab can be hard to distinguish from the Purple-mottled Shore Crab (C. granulosus) in fact the only true way is to look at the underside of the crab if the area where the legs join the body of the crab has a tuft of small hairs then it is C. audouinii if it does not then it is C. granulosus.

The carapace of this crab is smooth and lacks any notches the colour can vary greatly much like others in this family.
How to identify Cyclograpsus audouinii?
What habitats does Cyclograpsus audouinii live in?
Can be found under rocks at all intertidal and subtidal levels
What is the distribution of Cyclograpsus audouinii?
Most of Australian coasts including around Tasmania excluding the NT
How big does Cyclograpsus audouinii grow?
Can grow to around 40mm across the carapace
Disclaimer: A lot of work goes into trying to identify and ensure accurate identifications are made and that the listed Descriptions, Sizes, Habitats and Distribution information is as accurate and valid as possible. Unfortunately, information in this arena is ever changing and as such no guarantee can be offered that it is correct or currently valid as a result the information is provided as a guide, and it is always suggested that you do a little research to ensure you have the latest and most accurate information. View the reference's or bibliography I welcome any feedback and comments on the information provided.