Biologists from the University of California at Riverside have discovered the fossil of an ancient animal, which is about 555 million years old, a possible ancestor of humans and most animals. This was reported in the journal Proceedings of the National Academy of Sciences.
We are talking about the tiny worm-shaped creature Ikaria wariootia (up to 7 mm in length and about 1–2.5 mm in width). It belongs to the group of bilateral organisms. Bilaterials are almost 99% of all known animals – 1.6 million species described, as well as people.
Bilateria have a symmetrical structure (the body can be divided into left and right halves), as well as the oral opening and intestine. It was the development of bilateral symmetry that was the most important step in the evolution of the animal world, since organisms had the opportunity to move independently and purposefully.
Ikaria wariootia lived on earth during the Ediac period of the Proterozoic era (approximately 635–541 Ma ago). Then our planet was already inhabited by multicellular organisms.
Evolutionary biologists previously predicted that the oldest bilateria would be found, while it would be a simple and small creature with primitive sense organs. Fifteen years ago, traces of the movement of ancient bilateria in sediments of the Precambrian period were discovered in Australia, but all this time scientists could not find fossils.
The find was named in honor of the Adnamathan people who lived in this place. “Ikaria” in Adnamathanian language means “meeting place”, and “variutia” comes from the Warioota stream, which descends from the mountains near the site of the discovery of the fossil.