Sea Urchins

Extinct Sea Urchin, Sinaecidaris tauozensis [Taouz, Morocco]

Sea Urchins, of the class Echinoidea, are a type of echinoderm, much like brittle stars and jimbacrinus. Echinoderms, of the phylum Echinodermata, existed Precambrian over 600 million years ago. They have only been found in marine waters with 6,000 species still in existence. They are characterized by a well-developed water vascular system and by their mesodermal skeleton.

Extinct Pencil Urchin, Acrocidaris nobilis [Jurassic Period/LaRochelle, France]

Of the thousands of species of echinoderms, only about 700 species are sea urchins. As with most within the phylum Echinodermata, adult sea urchins have a fivefold symmetry called pentameral. They have characteristic long spines and a spherical shape. These spines serve not only as protection, but also as a way to move and a habitat for other creatures such as fish. Sea urchins feed on organic matter with one of their primary food sources being seaweed.

From the newest fossil collection at the Heard Natural Science Museum and Wildlife Sanctuary.