From ScienceDaily:
The origin of animals was one of the most important events in the history of Earth. Beautifully preserved fossil embryos suggest that our oldest ancestors might have existed a little more than half a billion years ago.
…
However, using a recently developed relaxed molecular clock method called RelTime, a team of scientists at Oakland (Michigan) and Temple (Philadelphia) dated the origin of animals at approximately 1.2 billion years ago reviving the debate on the age of the animals.
Puzzled by the results of the American team, researchers from the University of Bristol and Queen Mary University of London decided to take a closer look at RelTime and found that it failed to relax the clock. Their findings are published in the journal Genome Biology and Evolution.
Professor Philip Donoghue from the University of Bristol’s School of Earth Sciences, said: “What caught our attention was that results obtained using RelTime were in strong disagreement with a diversity of different studies, from different research groups and that used different software and data, all of which broadly agreed that animals are unlikely to be older than approximately 850 million years.” Paper. open access – Jesus Lozano-Fernandez, Mario dos Reis, Philip C.J. Donoghue, Davide Pisani. RelTime Rates Collapse to a Strict Clock When Estimating the Timeline of Animal Diversification. Genome Biology and Evolution, 2017; 9 (5): 1320 DOI: 10.1093/gbe/evx079 More.
Half a billion years? 850 million years? 1.2 billion years? It’s safe to say that dating of the origin of animal life is hardly, at present, an exact science.
See also: Researchers: Human-like ways of thinking evolved much earlier than thought Of course, 1.8 mya is so long ago that one can only wonder what humans were doing in the meantime, that meant that their thought capacities didn’t evolve faster.
and
Bonobos closer to humans than common chimpanzees are? The authors don’t say so, but one possibility is that the accepted dating is off.