The group of paleontologists discovered fossils of the oldest animal that had a skeleton. Ancient organism called Coronacollina acula, lived on Earth about 560-550 million years ago, during the Ediacaria, that is, until the explosion of the biota and diversification of organisms on the planet occurred in the Cambrian period.
This finding was in response to some questions about the evolution of life - particularly the very early life - on the planet who still care about academics. This allowed them to understand why the animals are dying, and how organisms respond to environmental changes. In addition, the discovery could also help scientists to recognize the signs of life elsewhere in the universe.
Ediacaria geological period (from the name of a hill Ediacaria in South Australia), lasted approximately 630-542 million years BC. Cambrian period marked by rapid diversification of life forms on Earth, as well as the rapid growth of mineralized organisms lasted 542-488 million years ago.
"Prior to the Cambrian period, it was realized that the earth existed only animals with the bodies of the soft tissues, without any hard parts" - said Mary Drosera (Mary Droser), professor of geology at the University of California, Riverside, whose research team made the discovery in South Australia. "But now we have an organism with individual skeletal parts of the body, which appeared long before the Cambrian period. Consequently, it is the oldest animal with hard parts of the body, which appears to be a structure which supports the animal."
For fossil Coronacollina acula seen that the animal had various body parts ranging from several millimeters to two centimeters in depth and about 3-5 centimeters in length. It is remarkable that this ancient animal is very similar in structure to the Cambrian marine sponges that have arisen much later - tens of millions of years.
"So, it forms a link between the two time intervals," - said Professor Drosera. "We called this organism," a harbinger of Cambrian structural morphology, "that is a precursor of organisms existed in the Cambrian period. This startling discovery is a clear example of the first appearance of one of the major innovations in the evolution of animals."
According to Drosera, the occurrence Coronacollina acula indicates that the skeleton as the biological feature of many of the animals did not appear suddenly, as the result of a chain of events and is regarded as one of the evolutionary advantage of all the inhabitants of that period. Scientists note that the skeleton Coronacollina Acula was not merely a rigid base, and had a couple of joints, which are the result of its own evolution, and provide the body with the necessary flexibility to move around.
"The fate of the earliest animals Ediacaria has long been a subject of debate, in which some researchers have argued that these animals became extinct before the Cambrian period," - said Drosera. "However, our finding suggests the opposite."
The findings are published in the online version of the journal Geology.
The researchers also reported that Coronacollina acula lived on the seabed, but so far they can not tell exactly what he ate, but suspect that lifestyle Coronacollina Acula was similar to the way of life of the sea sponge. The body of the animal was formed quite a strange way: from the center of a length of only a few centimeters departed in different directions several limbs rays. But as the animal used them as yet unknown. The method of reproduction it is also still a mystery.