Clypeaster humilis
(Leske, 1778)
Enter the name for this tabbed section: Description
The sand dollar Clypeaster humilis urchin is probably quite common, but because of its habitat (sandy to muddy areas) and its burrowing life style, it is not often observed. The pentaradial symmetry is illustrated by the 5 petals on the aboral side of the test that are formed by the rows of tube feet. The mouth is nearly central whereas the anus is located orally, very close to the margin of the test which is thin.
The tests of dead urchins is sometimes seen as part of the "covering" material or Toxopneustes pileolus which lives in a similar environment and are often found on beaches after a storm with other irregular sea urchins.
The tests of dead urchins is sometimes seen as part of the "covering" material or Toxopneustes pileolus which lives in a similar environment and are often found on beaches after a storm with other irregular sea urchins.
Enter the name for this tabbed section: Distribution
This species is widely distributed in the Indian Ocean and the western Pacific Ocean and was observed in most locations where sand is present.
Enter the name for this tabbed section: Ecology and Biology
Clypeaster humilis is a typical sand dollar. It lives burried in coarse or fine sediment from which it extract the organic matter. When place on the sediment, it reburies itself in about a minute, using its hair like spines on the aboral surface to cover itself with the sediment at the margin of the test. The spines on the oral surface push the sediment towards the margin.
Several specimens of C. humilis were found parasited by a small micro-gastropod of the family Eulimidae. In this large family of echinoderm parasites, the snail pierces the test and with an elongated proboscis, sucks the internal fluids of its host.
It is likely a lot more common that the limited observations suggest, because of its burrowing habits.
Several specimens of C. humilis were found parasited by a small micro-gastropod of the family Eulimidae. In this large family of echinoderm parasites, the snail pierces the test and with an elongated proboscis, sucks the internal fluids of its host.
It is likely a lot more common that the limited observations suggest, because of its burrowing habits.