The Dhaka Times Desk 507 years i.e. the longest recorded living organism is a mussel.

This mussel has entered the list of oldest organisms in the world. Scientists previously estimated the age of this oyster named Ming to be 405 years. At first it was thought so, but scientists say that this oyster was actually 102 years older than expected. As such, the oyster was born in 1499!
Accidental: The mussel's unfortunate death occurred during age determination, scientists said. The oyster died soon after they opened its shell for research. The mussel was found alive in Iceland in 2006 by climate change experts at Bangor University in North Wales. Since then, scientists have worked to determine his age. After a long research, they said that its actual age is 507 years and it was the oldest living organism in the world. Source: Online.