The Sand Dollar Urchin (Clypeaster australasiae) is a temperate water urchin species that belongs to the echinoderm family Clypeasteridae. It is endemic to Australia and is known to occur from Bowen in Queensland down to Lakes Entrance in Victoria. It is known to occur from depths of 0 to 75 metres. It is coloured light or dark brown and has a 5 petal marking on the upper surface. This species lives on sand and can be occasionally found on rocky reefs however it is not a burrowing species. It feeds by extracting nutrient coated sand particles and micro organisms from the sand as it moves along.
The test of the Sand Dollar Urchin (Clypeaster australasiae) grows to a diameter of at least 13cm.