Secrets locked in amber for 50 million years

Scientists find missing link with age of dinosaurs, writes John Lichfield
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THERE is a mayfly, supposed to live for a day, which has survived for 54 million years, its fragile wings still spread as if in flight. There is a bizarre creature, half cockroach, half praying-mantis, which defeats all scientific classification.

There are two midges frozen in the act of making love, a coitus interruptus which has lasted for 500,000 centuries. There are ancient ants, bees, wasps, termites, ear-wigs, beetles, all from species previously unknown, all minutely and perfectly preserved in amber found in a sand-pit in Picardy, 50 miles north of Paris.

So far 10,000 pre-historic insects have been recovered from this entomological gold-mine, all from extinct and unknown species. At least 500 types have been identified and there may be many to come. The sand-pit is thought to contain as much as 30 tonnes of amber, of which only 1 per cent has been recovered so far.

It is a find of immense scientific importance, because the insects come from a period which is a closed book to entomologists: 10 million years after the disappearance of the dinosaurs but before the development of insect and animal life as we know it today. "It is, if you like, a missing link," said Dr Andre Nel, of the Natural History Museum in Paris, who is leading the team recovering and classifying the insects.

Until this week, it was uncertain whether the sand-pit itself would survive beyond this month. The former British gravel and sand extraction company, Redland, now part of the French group, Lafarge, was due to abandon the pit next week and allow the ground water to rise, concealing the remaining amber. The company has now agreed to make a generous contribution to the scientific investigation of the site, including paying for pumping water from the pit until at least October.

Amber comes from the resin of trees and plants, buried between layers of sediment or sand and then fossilised over thousands of centuries. Any insects trapped and drowned in the resin are preserved forever. Similar finds have been made all over the world. (The scientifically dubious plot of the novel Jurassic Park - and the film of the book - is based on the notion that dinosaurs could be recreated from the DNA of their blood, extracted from a contemporary biting insect, preserved in amber).

The find in Picardy was originally made by an amateur paleontologist, Gael de Ploeg, in 1996.

It is the first anywhere in the world from the lower Eocene era, around 53 or 54 million years ago; all previous amber finds have been from much earlier or much later.

When these deposits were laid down, the area was a tropical region, bisected by a vast west-to-east flowing river.

The amber is dug and sieved in small, honey-coloured globules from the sand, gravel and charcoal which formed the ancient river bed. Other fossils have been found in the pit, including parts of unknown mammals and hundreds of pieces of fossilised crocodile droppings.

"We do not wish to identify the site because we want no trouble with robbers," said Professor Jean-Jacques Menier, in charge of the museum's project to create a permanent database of the Picardy insects. "Amber is much sought after by some people to make jewellery. This is, in fact, a much too fragile kind of amber for that purpose. But that would not stop the robbers."

The scale of the finds in Picardy - and those expected in the next few months - has overwhelmed the capacity of the French entomological community. Professor Menier is putting together an international scientific foundation to study and classify the insects, drawing together experts from Britain, Spain, the United States and Russia. And could these experts, or others, extract DNA and re-create insect species which have not existed for tens of millions of years? Or bring back to life the ancient crocodiles or mammals which may have been bitten by the insects? Dr Nel and Professor Menier can scarcely conceal their merriment. Amber, they explain, is not fully air-tight. Any DNA found in an insect fossilised in amber would be hopelessly incomplete or, more likely, be the DNA of some intruding bacteria.

Oh, well, just an idea.