Researchers who discovered a clam seven years ago have accurately aged the mollusk to be 507 years old, the world's oldest living animal before they killed it.

According to USA Today, the researchers killed the animal when they cracked its shell open. They originally believed the animal to be 405 to 410 years old, a record on its own, but further analysis said otherwise.

The scientists opened the clam reportedly to count the rings on the inside of its shell, named Ming, leading to its demise. The rings were too close together anyway and the scientists instead counted the rings on the outside, meaning Ming may have been able to live on.

Bangor University's School of Ocean Sciences originally found Ming during a 2006 field expedition. The researchers were exploring Icelandic coastal waters for a project aiming to measure climate change over the past 1,000 years, according to a press release.

Clams contain specific and valuable clues to climate change and have accurate records embedded in their shells. After determining the clam was very old, they involved world-leading experts to help give the animal a precise age.

"We got it wrong the first time and maybe we were a bit [hasty] publishing our findings back then. But we are absolutely certain that we've got the right age now," Bangor University researcher Paul Butler told ScienceNordic.

"On the outside, the mollusk shell is curved, and that makes it difficult to get the right angle for measuring and counting the growth rings," he said. "The growth rings are also better protected inside the hinge ligaments."

Royal Netherlands Institute marine biologist Rob Witbaard is confident that the team of scientists at least determined the precise age of the animal.

"The age has been confirmed with a variety of methods, including geochemical methods such as the carbon-14 method. So I am very confident that they have now determined the right age. If there is any error, it can only be one or two years," he said. "I had several specimens in my collection that had more than 100 growth rings, but I found it difficult to convince people that they were really that old."