- Echinothrix calamaris
Taxobox
name = Double spined urchin
regnum =Animal ia
phylum =Echinodermata
classis =Echinoidea
subclassis =Euechinoidea
superordo =Diadematacea
ordo =Diadematoida
familia =Diadematidae
genus = "Echinothrix "
genus_authority = Peters, 1853
species = "E. calamaris"
binomial = "Echinothrix calamaris"
binomial_authority = Pallas,1774 The double spined urchin or banded sea urchin, "Echinothrix calamaris", is a urchin, with a test (shell) diameter of about 5 cm. It has two sets of spines, shorter closed spines which are dark in colour and can deliver a nasty sting, and longer open ended spines that are often banded.
It is found in the
Indo-Pacific region, on back reefs. It is active at night, hiding in crevices or under rocks at night.Many juvenile fish of the family "
Apogonidae " (cardinal fish ) may hide in the spines for protection.The differences between "Echinothrix calamaris" and "
Echinothrix diadema " are: the spines of "E. diadema" are not banded, there is only one layer, and they are darker. The more similar species is "Diadema savignyi " (which has banded spines) - the distinguishing feature being that the banded spines of "D. savignyi" are closed at their ends.
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