| P number: | P550280 |
|---|---|
| Caption: | Conulus albogalerus, a fossil echinoid. |
| Description: | Conulus ranges through out the late Cretaceous (65 to 98 million years ago) and is found at various horizons within the English Chalk. Regular echinoids have the mouth in the centre of the underside of the test whereas the anus is on the top of the echinoid. In irregular echinoids, like Conulus, the mouth is towards the front of the test and the anus has moved either to the end of the echinoid or to the underside. The test of Conulus albogalerus is a high dome, almost a rounded triange in side view and its mouth is in the centre of the underside. It may at first glance appear to be a regular echinoid, but evolution has taken the anus to the margin, almost to the underside, so making it irreguar. The ambulacra are not petal-like, but are made up of many small plates. All the plates are covered by small tubercles where the spines were once attached. 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: | Landscape |
| Size: | 423.83 KB; 1000 x 903 pixels; 85 x 76 mm (print at 300 DPI); 265 x 239 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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