The first large complex organisms – known as the Ediacarans – appear in the fossil record about 570 million years ago, just before the Cambrian explosion of modern animal life. Their alien body shapes have created confusion over whether they were primitive animals, other complex lifeforms like lichen or giant amoebas, or failed experiments of evolution.
Now, Jochen Brocks at Australian National University and his colleagues have found fat molecules in 558 million-year-old fossils of Dickinsonia – a type of Ediacaran – that confirms it was an early animal.
The researchers collected the fossils from sandstone cliffs in a remote area of the White Sea region of Russia. The cholesterol-like molecules preserved in them are found in almost all of today’s animals, but have low abundance in other lifeforms like bacteria, lichen and amoebas. “It tells us this creature in fact was our earliest ancestor,” says Brocks.
Read the rest over at NewScientist.
(Photo: Ilya Bobrovskiy / Australian National University)