The class of marine animals known as cephalopoda – which today includes squids, octopuses, and cuttlefishes – may have been around Earth 30 million years earlier than previously thought, according to a study new.
In addition, if we need to reset the times on the appearance of cephalopods, it may be necessary to re-examine the evolutionary history of invertebrate organisms, given their importance. these creatures in the overall picture of life on the planet.
At the heart of the new research is the discovery of several 522 million-year-old cone-shaped fossils on the Avalon peninsula in Newfoundland, Canada, which contain some telltale features that mean they could be referred to as cephalopods.
Longitudinal sections and crosses of the recently discovered fossils. (Gregor Austermann / Communication Biology)
“If they really were to be cephalopods, we had to backfire a background of cephalopods into the Cambrian period,” says geologist Anne Hildenbrand from the University of Heidelberg in Germany.
“That would mean that cephalopods appeared at the beginning of the evolution of heterogeneous organisms at the time of the Cambrian eruption.”
Until now, it was thought to be the earliest cephalopods Plectronoceras cambria – tiny molluscs with cone-like shells that lived in late Cambrian, about 490 million years ago.
As far as we know P. cambriaanatomy is based on incomplete fossils, these new finds are similar enough to link the species. They are also diverse enough to support the notion that millions of years of evolution could separate them.
For example, one of the features that scientists have seen in several of the calcareous shells from the Avalon Peninsula is evidence of a siphuncle: a tube of material that helps to drain water from the shell, regulates levels of nitrogen, oxygen, and carbon dioxide, and strength control.
However, traces of siphuncle are not present on all recently discovered fossils, and its location is slightly different from where one would expect. After carefully examining the similarities and differences, the researchers believe they have discovered fossils that are actually an older form of cephalopods.
“The presence of a siphuncle, septal neck, and connective ring is usually seen as key features for differentiating early fossil cephalopods from other septate or chambered organisms,” the researchers write in their paper.
“However, some authors have also identified fossil shell material that does not have these properties to cephalopods.”
By changing the timeline cephalopods would appear before the arrival of certain eurthropods (including insects and barks), going back from the Terreneuvian part of the geological chart.
As the first organisms capable of moving up and down in the water – thanks again to that siphuncle – and settling in the open ocean, cephalopods play an important role in the history of early evolution, and as that is, experts want the time of their crisis to be right. .
Classification of creatures can be quite difficult, even when we are not talking about more than half a billion years of fossil remains, but the researchers hope that further studies and more discoveries will help their claims. Now, the hunt is on to find better preserved samples from the same area.
“This discovery is remarkable,” said geologist Gregor Austermann of the University of Heidelberg. “In scientific circles there has long been a suspicion that the evolution of these advanced organisms had begun much earlier than previously thought. But there was a lack of fossil evidence to support this theory.”
The research was published in Communication Biology.