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     When scientists accidentally killed what turned out to be the world’s oldest living creature, it was bad enough.

     Now, their mistake has been bigger after further research found it was even older – they calculated less 107 years than it.

     The ocean quahog - a type of deep-sea clam - was dredged (捞取) 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 studied it and concluded it was 400 years old.

     The discovery made it into the Guinness Book of World Records however by this time, it was too late for Ming the mollusc(软体动物) – named after the Chinese dynasty on the throne(君主) when its life began.Unfortunately researchers who calculated Ming’s age killed it instantly by opening its shell.

A quahog’s shell grows by a layer（层）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.

        The researchers opened the ancient clam up to judge its age by counting growth rings inside.But the rings were so close together that scientists ended up having to count the rings on the outside to be accurate, leading CBS to point out that Ming could have lived on, had scientists just started there.

        Dr Paul Butler, from the University’s School of Ocean Sciences, said: “We got it wrong the first time and maybe we were a bit hurry publishing our findings back then. But we are absolutely certain that we’ve got the right age now.”