At the Ohio State University scientists have found a new creature that is about 500 million years old. It is an echinoderm, making it related to your modern day sea urchins, sea stars, sea cucumbers etc. This fossil is special in that it demonstrates evolution by echinoderms that parallel important ecological changes that took place in marine sediments.
The full discovery took about 30 years and the results were published in the Bulletin of Geosciences. The work provides some insight into how the creatures made the evolutionary leap. The leap saw the echinoderms switch from living to sediment grains held to together by algae to being able to live attached to hard or shell like surfaces the way their modern decedents do.
This new sea critter got named Totiglobus spencencis and lived in the Cambrian Period (about 507 million years ago, the Earth being about 4.5 billion years old). The fossil itself was found in the shale of Spence Gulch, eastern Idaho, by a family of fossil hunters in 1992.