Life on earth was born … in the water, as shown by the oldest fossiliferous beds in the world. A new discovery made in Canada, however, questioned at least in part this statement: some of the first forms of animal life, lived about 500 million years ago, they already managed to resist aireven if for limited periods of time before having to return to the water to breathe. The study that describes these fossils is published in the magazine Paleontology.
Water but not only. The fossils in question come from the Pika Formation, which is located in the Jasper National Park in Canada and which is one of the most famous in the world relating to the period Cambriano, 500 million years agowhen animal life was at his beginning and was taking his first steps underwater.
Discovered in 1999, the remains were analyzed only recently, and to hit the paleontologists was above all the substrate on which they were found: they were thin layers of clay crossed by cracks, which indicate that theirs Nature was “muddy” – A tide plain occasionally exposed to the air when the water retreated. We do not know if it was a regular or occasional event, but what is certain is that The animals found in the clay had every now and then cavated it without water.
The first terrestrial animals? The discovery is particularly important because the fossils of the Pika Formation are coeval of those of other well -known formations, first of all the clay of Burgess, one of the richest Cambrian deposits in the world formed in deep waters. The clays of the Pika were instead “ampiby”, and despite this condition they host many animal species.
These species show that, already 500 million years ago, they existed animals that were partially adapted to the aireven if obviously only for short periods of time: for The first fully terrestrial animals must be waited for another hundred millions of years.
