From the point of view of how little we know about them, they look so different. 500 million years ago, the mysterious creatures that lived in the oceans— headless, limbless creatures— seemed to be out of place with us in every way.
But new research suggests that this is not the case. In fact, scientists say, the Ediacaran biota — a group of ancient marine life that lived on Earth between 570 million and 539 million years ago — has many genetic similarities with modern prozoans, including humans ( multicellular animals ) .
Of course, this is not to say that the similarities between them are nearly inconceivable.
The paleontologist from the University of California explains: "None of them have heads or bones. Many of them may look like three-dimensional bath mats on the ocean floor, with rounded disc-like protrusions. ”
The paleontologist has some expertise in studying the strange creatures of Earth's distant past.
Above: Restoration of Ikaria Wariootia
A year ago, he presided over a study that identified one of the Ediacaran animals: Ikaria Wariootia, a strange, retarded worm about the size of a grain of rice that may have been the earliest ancestor of all symmetrical animals on both sides of the body.
However, not all Ediacaran animals are so closely associated with animals today.
During that period, there were more than 40 species that had been identified, including the most famous "oval Dickinson jellyfish," as well as another species named after Oba President Ma. Determining where their fossil forms should be located in the Tree of Life is not an easy task.
Above: Fossil specimen of Dickenson jellyfish
Paleontologists say: "These animals are so weird, so different, it is difficult to classify them as modern creatures just by observation. Also, we can't extract their DNA. ”
Since it was not possible to analyze the genetic data of these creatures first-hand, researchers could only extrapolate the conclusions they could draw from the fossils left behind by these creatures. Fortunately, these ancient imprints can reveal a lot.
In a new study, collaborated by paleontologists and experts from the Smithsonian National Museum of Natural History, the researchers looked at four representations of the Edicaran biota: Dickenson jellyfish, Ikaria, slug-like kimberian worms, and hemispherical tristar discworms.
Above: Kimberley fossil specimen
Based on observations of fossils, and our inferences about how these creatures might have moved their bodies, maintained themselves, and typically lived on the ancient seabed, the researchers suggest that these animals most likely contained a basic form of nervous system that was supported and regulated by the same type of gene regulatory elements that existing animals, including humans, still used today.
"This analysis suggests that in these early animals, there may have been multicellular, axial polar, muscular and nervous system genetic pathways," the researchers said. ”
Above: Fossil specimen of Samsung discworm
Taken together, these traits help better limit the phylogenetic status of several key Edicaran taxa and provide scientists with an idea of the evolution of early prozoans.
Specifically, in the new study, the team outlined a range of genes that may affect multicellular, immune, neurological, apoptosis (programmed cell death), axial patterns (distinguishing between the two sides of the body, such as anterior, posterior, left, right), and more.
While there's still a lot to learn about these truly ancient creatures, the biology that has linked us across millions of years suggests that they may not be as strange as they seem.
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