Exploring the evolution of life on this planet isn’t the easiest job. There’s a lot about it that scientists still don’t know as many life forms have gone extinct, taking away with them secrets about their ecosystem and environment. How an ancient life form morphed into the version we see today requires a lot of deductions and guesswork. Fossil records are helpful, but they are not always easy to find. However, in a lucky break for palaeontologists, an ancient starfish fossil has been uncovered that might be the "missing link" they had been searching for a long time.
The starfish fossil was uncovered in Morocco. It is reported to be 480 million years old and is key to understanding the relationship between today’s crinoids and their long-gone ancestors. The newly discovered fossil is now being recognised as the oldest known starfish on the planet. Formerly, the oldest starfish specimen on record was 50 million years younger. The discovery was made in Fezouata shale of the Anti-Atlas mountain range.
It is named Cantabrigiaster fezouataensis. The experts suggest it has very intricate designs and patterns and feathery arms which are still visible on the dead fossil.
Evolutionary palaeoecologist Aaron Hunter from University of Cambridge said this new find is “incredibly exciting.” He said it will be helpful in mapping out the evolution of starfish.
The fossils belong to one of the most important periods of Earth existence- the Great Ordovician Biodiversification Event (GOBE).
“If you went back in time and put your head under the sea in the Ordovician, then you wouldn't recognise any of the marine organisms — except the starfish, they are one of the first modern animals,” he added. The era is considered as a period of evolutionary radiation where many dominant species emerged and changed the facet of the planet. The GOBE radically expanded marine diversity. Nearly 70% of the life that evolved during the previous such event, The Cambrian Explosion, was eradicated.
The fossil is reported to be lacking 60% of today’s starfish features. As a result, it looks like a hybrid between today’s starfish and older crinoids. They have compared the structure to a sea lily, an organism with wavy-armed filter-feeders that are embedded in the seabed.
The team went through extensive searches of older archives to find similarities with other echinoderms. This is the same group which contains animals like starfish and sea cucumbers. One of the key focuses of future research will be to understand why and how today’s starfish developed five arms. This shape is suggested to be an adaptation during the course of evolution but experts are still unclear why.
The study about the newly-found fossil has been published in the journal Biology Letters.