Not only do the Cephalopods have an alien appearance and are extremely intelligent, but they already inhabited this world far earlier than we believed until now.
The class of marine animals known as cephalopods – which today includes squid, octopus and cuttlefish – may have existed on Earth 30 million years earlier than previously thought, according to new research.
Furthermore, if we need to reset cephalopod occurrence times, it may be necessary to re-examine the entire evolutionary history of invertebrate organisms, given the importance of these creatures in the bigger picture of life on the planet.
The key to the new research is the discovery of several 522-million-year-old cone-shaped fossils on the Avalon Peninsula in Newfoundland, Canada, which display certain tell-tale features that mean they could be classified as cephalopods.
“If they really were cephalopods, we would have to trace the origin of cephalopods to the early Cambrian period,” says geoscientist Anne Hildenbrand of the University of Heidelberg in Germany. “That would mean that cephalopods arose early in the evolution of multicellular organisms during the Cambrian explosion.”
Until now, the earliest cephalopods were thought to be Plectronoceras cambria , small mollusks with cone-shaped shells that lived in the late Cambrian period, approximately 490 million years ago.
While our knowledge of the anatomy of P. cambria is based on incomplete fossils, these new findings are similar enough to suggest a connection between the species. They are also different enough to support the hypothesis that millions of years of evolution could separate them.
For example, one of the characteristics that scientists have detected in several of the calcareous shells of the Avalon Peninsula is evidence of a siphon: a tissue tube that helps drain water from the shell, control nitrogen levels, oxygen, and carbon dioxide, and buoyancy control.
However, signs of a sifunculus are not present in all newly found fossils, and its position is slightly different from where it would be expected to be. After a thorough analysis of these similarities and differences, the researchers believe they have found fossils that are in fact an older form of cephalopods.
“The presence of a sifunculus, septal necks, and a connecting ring are commonly regarded as key features in distinguishing early fossil cephalopods from other chambered or septate organisms,” the researchers write in their paper. “However, some authors have also assigned fossil shell material lacking these characteristics to cephalopods.”
Adjusting the timeline would mean that cephalopods emerged before certain euarthropods (including insects and crustaceans), which date from the Terreneuvian part of the geological record.
As the first organisms able to propel themselves up and down in the water, thanks again to that sifunculus, and settle in the open ocean, cephalopods play an important role in early evolutionary history, so experts want to determine the timing. correct of its appearance.
Classifying creatures can often be a complicated task, even when we are not talking about fossilized remains more than 500 million years old, but the researchers hope that more studies and discoveries will help verify their claims. Now, the search has begun to find better preserved specimens from the same area.
“This finding is extraordinary,” says geoscientist Gregor Austermann of the University of Heidelberg. ‘In scientific circles, it was long suspected that the evolution of these highly developed organisms had started much earlier than previously assumed. But fossil evidence to support this theory was lacking. ‘
The research has been published in Communications Biology .