According to a new study, an alien small fossil could represent the ancestor of all animal-like animals on the planet.
The 480-million-year-old fossil was excavated more than 17 years ago in the Moroccan desert, but its identity and evolutionary history have remained secret until now. Scientists have now formally described the specimen in new research published in the journal on Wednesday (January 20) Biology letters.
The new species, Cantabrigiaster fezouataensis, has the shape of a star, but lacks other characteristics that can be seen in one of the two starfish that live today: starfish and fragile stars (part of a subphylum called Asterozoa). Because the species did not have these characteristics – the long thin arms of the fragile star and the thick armor plates around a starfish – researchers concluded that it was therefore the ancestor of both.
“We discovered exactly how the first animal-like animal appeared and how it evolved into the two we have today, and which are almost everywhere in the ocean,” said lead author Aaron Hunter, a paleontologist in Earth Sciences. department at the University of Cambridge. “That’s what makes it special.”
Related: Photos: abundance of marine fossils discovered in Morocco
C. fezouataensis just on the ancient supercontinent of Gondwana, a large land mass containing parts of today’s southern continents. ‘You’re dealing with what may have been closer to what we think we should be Antarctica today, “Hunter told WordsSideKick.
The ancestor lived during the early Ordovician period (about 485.4 million to 460 million years ago) on an old reef with cold water, surrounded by mostly alien species such as giant filter feeds called anomalocarides. The more modern look of the starfish’s ancestor would have stood out in comparison.
The researchers are not sure what C. fezouataensis ate. Evidence of a jawbone suggests that it was probably not a filter feed like the anomalocarides in the same period and some of the brittle stars of today.
“We sit in a room and look at every feature of the animal,” Hunter said. They then compared these characteristics with those of live animals and those already identified in the fossil record. The team then used both biology and a mathematical algorithm to place these ancient starfish ancestors on a pedigree.
Starfish and brittle stars are two of the five living groups that together form a larger group or crown group, called thorny houses. The other three are hippos, cucumbers and Crinoidea (sea lilies and feather stars). C. fezouataensis has a similar arm structure to contemporary sea lilies, meaning that its lilies can trace their lineage to this ancient ancestral species.
The new analysis showed that C. fezouataensis first appeared during an important period known as the great event for biodiversity in Ordovician. “That’s when life is really going on in terms of diversity, and that the starfish is one of the first animals we will recognize in the ocean today,” Hunter said.
Use C. fezouataensis as a point of departure, it is now possible to link starfish-like animals from about 480 million years ago to more recent fossils and then to modern-day animals.
“This is a fascinating study,” Bertrand Lefebvre, a paleontologist at the French National Center for Scientific Research (CNRS) and the University of Lyon, told WordsSideKick in an email. Lefebvre helped collect material from the site in Morocco, known for producing extraordinarily well-preserved fossils, and he also reviewed the magazine article. However, he was not an author of the article.
‘This new early starfish from Morocco offers an interesting look at the early evolution of the asterozoan and the origin of the echinoderm crown group’, ‘the larger group that includes starfish and fragile stars, as well as hippos, seals and cucumbers,’ said Lefebvre. .
But more research is needed on animals from the late Cambrian period (497 million to 485.4 million years ago) to fill the gap between the earliest spiny skins and all five of the groups we see today, Lefebvre said.
Originally published on Live Science.