If we think of a starfish, we imagine a small marine animal with five pointed arms. However, they have not always had this appearance. A small fossil, which is approximately 480 million years old, was unearthed in the Moroccan desert more than 17 years ago. And, although scientists were investigating its identity, it has not been until now that they have been able to discover that it was a species of starfish, as a study published in the journal Biology Letters maintains .
This species ( Cantabrigiaster fezouataensis ) is star-shaped but lacks elongated arms and thick structure, so the researchers concluded that it was the ancestor of starfish. Thus, as the researchers argue, the species evolved into the two main species we have today (starfish and brittle stars).
This animal lived on the ancient supercontinent of Gondwana, which existed approximately 500 million years ago. In addition, it was in what was then a cold-water reef, coexisting with other alien-looking species (mostly filter-feeder animals, such as the extinct anomalocarids). Likewise, although the researchers are not sure how this animal fed, due to the shape of its jaw they consider that it did not eat like current stars.
Starfish and brittle stars are part of a larger group, the echinoderms. Also in this category are sea urchins, sea cucumbers, and crinoids (also known as sea lilies). In addition, the discovered species had a similar appearance to current sea lilies, which is why it is one of its ancestors.
On the other hand, thanks to research it is possible to link current animals with species that existed 480 million years ago, as Bertrand Lefebvre, one of the scientists involved in the project, maintains. Likewise, this starfish provides relevant information on the evolution of echinoderms, although the difference between the first echinoderms and the five groups that exist today is still unknown.
