St Andrews professor unearths new origins of animal life
Credit: Tony Prave
St Andrews researchers, acting as part of an international team, have dug up new evidence which may shed light on the origins of animal life.
Sponge-like fossils were recently unearthed in the Namibian desert by Dr. Tony Prave, the University’s Director of Geoscience Teaching, Dr. Bob Brain, from South Africa’s Ditsong Museum, and Mr. Karl-Heinz Hoffmann of the Namibian Geological Survey.
At between 760 and 550 million years old, these could be proof that animal life emerged tens of millions of years earlier than was previously believed.
The sub-millimetre-sized fossils are called Otavia antiqua and look like ‘hollow globs’, which could class them as the stem group organism, the ancestor of all animals.
According to Dr. Prave, the minuscule creatures were pierced by different-sized openings that were probably used to pass nutrients into their bodies. The researchers also found a ‘network of internal passageways’ thought to be a primitive gut.
It is thought that these fossils were preserved in ancient marine rocks during the time when the earth was undergoing its most extreme climactic changes, such as the ice age, colloquially known as ‘snowball earth’.
‘What is remarkable is that this organism appears to have evolved before, and survived through, the environmental extremes of snowball Earth,’ said Prave. ‘This implies that the causes and conditions for the evolutionary leap from bacteria to animals have to be searched for much deeper in time than previously thought.’
The team’s findings reflect predictions made by geneticists who have studied the ‘molecular clocks’ of other species in an attempt to more accurately date to the origins of early life forms.
Prior to this discovery, it was thought that the first animals did not emerge until 600-650 million years ago.
The project involved a team of ten scientists from Namibia, South Africa, Australia and the UK, including Donald Herd and Stuart Allison of the University of St Andrews. Their collective findings were published in the South African Journal of Science.
