slate-pencil urchin
Quick Summary
The slate-pencil sea urchin (Heterocentrotus mammillatus) is a large, spiny marine invertebrate found in the Indo-Pacific. It is characterized by its stout, heavy spines, which can be up to 12 cm long and are thick enough to be used for writing, resembling slate pencils.12
Sea urchins, in general, are part of the phylum Echinodermata and possess a globular body with a skeleton called a test. They have tube feet for movement and feeding, and a complex dental apparatus known as Aristotle's lantern, used to scrape algae and other food from surfaces. Sea urchins play various roles in their ecosystems, sometimes controlling seaweed growth on coral reefs, while other species can accelerate shoreline erosion or devastate sea-grass beds.23
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