| P number: | P550278 |
|---|---|
| Caption: | Clypeaster rosaceus, a Recent echinoid. |
| Description: | Clypeaster evolved during Eocene times, about 40-50 million years ago, and is still found living today (the illustrated specimen came from subrecent deposits). It is generally found in shallow marine waters, close to shore, where it partially buries itself in the sand and feeds on the small particles of detritus present in the sediment. Clypeaster rosaceus has a medium to large test that forms a low, oval dome. The five groups of plates forming the ambulacra make a large, slightly inflated, petal-like pattern on the upper surface of the animal. These plates are perforated by many pores including slit-like pores, from which the tube feet extended. The remaining plates (interambulacra) are also covered in pores. The mouth and the anus are in the centre of the underside (not seen in the illustration). Echinoids (sea urchins) have lived in marine habitats since the Ordovician times, about 450 million years ago. They still live today, inhabiting many shallow, near shore seas around the world. As fossil echinoids resemble living species, we have an idea how they must have lived. They had spines which are used for protection. Some species protected themselves from carnivores by having poison-tipped spines while others had large, unpalatable solid spines. Echinoids burrowed into the sand or crawled over the sea floor on their tubed feet, which extended from the paired pores on the star-like or petal-like areas (the ambulacra). They grazed and scavenging algae and plants or ate small particles in the sandy substrate. |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Portrait |
| Size: | 484.19 KB; 858 x 1001 pixels; 73 x 85 mm (print at 300 DPI); 227 x 265 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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