Appearance and lifestyle:
Rough pencil urchin's (Prionocidaris pistillaris) have large heavy spines which are often sold as ornaments. The spines are initially purple, but they usually get covered with algae, so the colour is hidden except at the base. Like other sea urchins, the rough pencil urchin belongs to the phylum Echinodermata. All sea urchins are covered with spines (hence their name: ‘Echino’ means spiny and ‘derm’ means skin) which move on ball and socket joints. They use the spines to defend themselves against predators.
Habitat:
They are found in rocky reefs, and they live in shallow to mid deep waters.
Diet:
They feed on algae, small invertebrates, detritus and sponges.
Threats:
Overcollection, pollution, climate change etc.
Spines are initially purple
They use their spines for protection.