Oldest living creature discovered, then killed

It was bad enough when scientists inadvertently killed what turned out to be the world's oldest living creature.

Now, their mistake has been compounded after further research found it was even older than they first thought - 507 years.

The ocean quahog, a type of deep-sea clam, was dredged alive from the bottom of the North Atlantic near Iceland in 2006 by researchers.

They then put it in a freezer, as is normal practice, unaware of its age.

It was only when it was taken to a laboratory that scientists from Bangor University concluded it was 400 years old.

The discovery made it into the Guinness Book of World Records but, by this time, it was too late for Ming the Mollusc, named after the Chinese dynasty.

Now, after examining the ocean quahog more closely, using more refined methods, the researchers have found the animal was actually 100 years older.

A quahog's shell grows by a layer every year, in the summer when the water is warmer and food is plentiful.

It means that when its shell is cut in half, scientists can count the lines in a similar way trees can be dated by rings in their trunks.

But because the quahog was so old, many of the rings had become compressed.

It means the mollusc was born in 1499 - just seven years after Columbus discovered America and before Henry VIII had even married his first wife, Catherine of Aragon in 1509.

Scientists say they can study the clam's layers to find out about sea temperatures and water masses from thousands of years ago.