A clam dredged up off the coast of Iceland is thought to have been the longest-lived animal discovered. Scientists said the mollusc, an ocean quahog clam, was aged between 405 and 410 years and could offer insights into the secrets of longevity. Researchers from Bangor University in north Wales said they calculated its age by counting rings on its shell. According to the Guinness Book of Records, the longest-lived animal was a clam found in 1982 aged 220. Unofficially, another clam – found in an Icelandic museum – was discovered to be 374-years-old, Bangor University said, making their clam at least 31 years older.