The oldest known individual animal was a clam that lived over 500 years

An ocean quahog dredged off Iceland in 2006 turned out to be about 507 years old when scientists counted growth rings in its shell, the oldest known non-colonial animal ever recorded. It hatched around 1499 and was nicknamed Ming, after the dynasty ruling China when its life began.

— Paul Butler and colleagues, Bangor University, Ocean quahog (Arctica islandica) longevity study — Bangor University School of Ocean Sciences, age confirmed 2013