Echinodiscus auritus
Leske, 1778
Enter the name for this tabbed section: Description
This relatively large species of "sand dollar" has been observed on a few occasion both near Muscat and in the Arabian Sea. The test of Echinodiscus auritus is characterized by an overal triangular shape with wide rounded angles. In Echinodiscus auritus, the petals (representing the ambulacara) are only about 1/3–1/2 of the radius.
Two notches reaching 1/3 to 1/2 of the diameter of the test open on the posterior side of the test. It has some shape affinities with the "starship Enterprise" from the series "Star Trek".
As seen on the photograph, the spines are numberous and hair-like. It is their movement that allows the animal to bury itself and move in the sediment in search of food.
Two notches reaching 1/3 to 1/2 of the diameter of the test open on the posterior side of the test. It has some shape affinities with the "starship Enterprise" from the series "Star Trek".
As seen on the photograph, the spines are numberous and hair-like. It is their movement that allows the animal to bury itself and move in the sediment in search of food.
Enter the name for this tabbed section: Distribution
It has only been photographed in two locations but is likely considerably more widespread.
Worldwide, it is known from the Red Sea to New Caledonia and seem to prefer relatively shallow areas.
Worldwide, it is known from the Red Sea to New Caledonia and seem to prefer relatively shallow areas.
Enter the name for this tabbed section: Ecology and Biology
Both species of Echinodiscus have very similar life styles, living just under the surface of the sediment. It is likely a lot more common that the observation suggest, because of its burrowing habits. They are invisible and can only be found when the sand is disturbed. Test are sometimes found in large numbers on beaches after a storm or a anoxic event. Anoxic event take place when deep water, poor in oxygen is upwelled in shallow areas. The soft-sediment fauna, unable to escape dies.