April 28, 2005
A 15-year search for fossils in Africa has uncovered eight fish specimens that are 450 million years old – 50 million years older than any previously found in Africa
Dwain Eldred writes: Professor Richard Aldridge, of the Department of Geology at the University of Leicester, who co-led the scientific expedition, says the fossil discovery is among the most remarkable and exciting ever to be found on the continent.
“These exciting fossils help to fill in a ‘missing link’ in the evolutionary history of the very early fishes. They are new to science, and we have yet to describe them and to give them a scientific name” he says.
Scientists working on fossils from the Cedarberg Mountains around Clanwilliam, South Africa, unearthed the ancient remains of forms that represent the evolutionary stage before the fishes had any skeleton at all.
The scientific team, led by Aldridge and Dr Hannes Theron of the University of Stellenbosch, South Africa, has been working on these deposits for 15 years and many remarkable fossils have been recovered.
Professor Aldridge says: “These new fish finds are among the most exciting ever. People may wonder how we know that these fossils are fishes, when we have no bones with which to identify them. The answer is that the exceptional preservation displayed in these rocks enables us to recognise the eyes, scales and even the liver of the animals. The impressions in the shale are very faint, but they are also very clear and diagnostic.”
The first, incomplete, specimen was found in 1994, just as the first elections in the new South Africa were taking place, and we nicknamed the fossil ‘Nelson’ in honour of the newly-elected President. In the eleven years since then no more specimens were found, until this year when the team, amazingly, recovered seven additional specimens.
Theron says: “These fishes come from a time in the remote past when Africa was in an ice age, and before any animals had colonised the land. They are preserved where they lived in a shallow sea fed by meltwaters from the receding ice sheets.”