Fossil sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from 3 to 10 centimetres (1.2 to 3.9 in) across. Common colors include black and dull shades of green, olive, brown, purple, and red. They move slowly, feeding mostly on algae. Sea otters, wolf eels, triggerfish, and other predators feed on them. Their "roe" (actually the gonads) is a delicacy in many cuisines.
The name urchin is an old name for the round spiny hedgehogs that sea urchins resemble.
The earliest echinoid fossils date to the upper part of the Ordovician period (c 450 MYA), and the taxon has survived to the present day as a successful and diverse group of organisms. Spines may be present in well-preserved specimens, but usually only the test remains. Isolated spines are common as fossils.
Fossil sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from 3 to 10 centimetres (1.2 to 3.9 in) across. Common colors include black and dull shades of green, olive, brown, purple, and red. They move slowly, feeding mostly on algae. Sea otters, wolf eels, triggerfish, and other predators feed on them. Their "roe" (actually the gonads) is a delicacy in many cuisines.
The name urchin is an old name for the round spiny hedgehogs that sea urchins resemble.
The earliest echinoid fossils date to the upper part of the Ordovician period (c 450 MYA), and the taxon has survived to the present day as a successful and diverse group of organisms. Spines may be present in well-preserved specimens, but usually only the test remains. Isolated spines are common as fossils.