(ORDO NEWS) — Due to the lack of material from the distant past, paleontologists sometimes have to make “scientific closures”, that is, to abandon previously described living creatures.
This is what happened to Brooksella, a 500-million-year-old animal fossil that turns out to be just a mineral, a bizarre nodule of silica.
The work of paleontologists is not easy. They are forced to equip expeditions to different parts of the globe and there to extract the remains of ancient organisms from sometimes capricious rocks.
Only a fraction of systematic groups always fall into their hands – due to the incompleteness of the fossil record – and what they get is usually only badly damaged fragments.
All this inevitably leads to errors and discrepancies – as, say, in the case of the types of tyrannosaurus rex or the systematic position of saccoritus.
Sometimes, as in the case of the Paleodiction, the question is radical: was this bizarre piece of rock ever alive?
The focus of her attention was by no means a new fossil – Brooksella sp.
It was discovered in the rocks of the Cambrian age in the United States back in 1896. Since then, for more than a hundred years, it has enjoyed a reputation among paleontologists as problematic.
Brooksella is something three-dimensional: five downward rays diverge from the center to the edges of her rounded “body”, which is why she resembles either a starfish or a wheel with spokes, but most likely a cupcake with a hole in the middle at the bottom. It was assumed that this hole is the mouth.
At first, brooxella was considered a jellyfish with tentacles (described as Brooksella alternata ), then a burrowing worm, an algae with a swollen thallus, and a glass (six-rayed) sponge.
Someone previously believed that brooxella are just petrified bubbles or, say, only traces of nutrition of some ancient organism, and not itself.
Now, however, the brooksella mystery seems to be solved , and rather prosaically at that.
A new study based on chemical analysis, radiography and micro-MRI showed that Brooksella sp. – it is rather not a living organism, but just a pseudofossil, a bizarre formation (concretion) of silica.
The same silicon oxide that ordinary river sand consists of, except perhaps with an admixture of calcite and organic residues.
In the studied samples, there were neither structures characteristic of the skeleton of glass sponges, nor anything that would indicate the growth of this formation as a living being.
On the whole, this “false fossil” differs nothing but a bizarre form from silica concretions similar to it, which, both in the Cambrian period and now, may well form on their own, without any help from living organisms.
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