An international team of researchers, together with paleontologists from the University of Manchester, discovered fossils with traces of life in the Corumba region (Western Brazil), which are approximately 500 million years old.
These tracks are tiny burrows made by unknown living organisms. The diameter of the holes is approximately 50 to 600 microns. That is, it turns out that the diameter of the living beings themselves is even smaller and approximately equal to the thickness of a human hair.
The fossils found date back to the so-called Edicar-Cambrian transition about 541 million years ago. For comparison, dinosaurs lived in the Mesozoic era - from 230 to 65 million years ago. According to scientists, the era of the Edicar-Cambrian transition is very important, since it was then that many groups of animals appeared, including those living today.
Scientists believe that the holes in the fossils were made by nematoid worms, reminiscent of modern roundworms, which lived in sedimentary rocks and moved in undulating translational movements.
To locate the tiny fossils, the scientists used X-ray microtomography technology, which uses X-rays to create a virtual 3D model of the object.