Ancient Starfish Fossil Unearthed in Morocco Sheds Light on Species’ Origins

It is a bizarre animal dating back 480 million years that was extracted from the fossil of Cantabrigiaster fezouataensis. It has characteristics similar to modern starfish and crinoids. This starfish has a 5-fold symmetry with 5 arms completely detached from the rest of the body. For the body, the axial part corresponds to modern models. As for the other parts, they seem to be non-existent and must have been added later in the course of evolution. Thus, with this discovery, scientists have the opportunity to provide clarification on the evolution and diversification of echinoderms, reports Sciences et Avenir.

The Feouzata clays are precious for paleontologists. They house thousands of fossils of soft-bodied animals that once lived in an open marine environment at the beginning of the Ordovician. Moreover, most of the species found there have nothing in common with those that exist today, apart from a few animals including Cantabrigiaster fezouataensis which resembles starfish. But it must be seen as a hybrid, as it lacks about 60% of the body plan of modern starfish.

The fossil discovered in Morocco was studied by a team from the University of Cambridge and its description was published in the journal Biology Letters. It was mainly compared with a hundred species close to true starfish or asterias. The researchers were able to establish family ties with other echinoderms. This allowed them to conclude that Cantabrigiaster fezouataensis is the oldest representative of asterias, although it does not possess all the characteristics.

The actors plan to expand their work to the search for early echinoderms. "One thing we hope to answer in the future is the reason why starfish have developed their five arms," said Aaron Hunter, lead author of the study, in a statement.