Oldest Tortoise in the World?

The Daily Mail ( UK) reported on 3rd December, 2008 that:

Jonathan the tortoise is believed to be 176-years-old and was about 70 at the time the black and white picture was taken.

He was captured munching on grass in about 1900 with a captured Boer War prisoner stood in the background looking at him.

A spokesman for the ST Helena island's tourist board said Jonathan is owned by the St Helena government and lives in the specially built plantation on the governor's land.

He said: 'Jonathan is the sole survivor of three tortoises that arrived on St Helena Island in 1882.

'He was already mature when he arrived and was at least 50-years-old.

'Therefore his minimum age is 176-years-old. He is the oldest inhabitant on St Helena and is claimed to be the oldest living tortoise in the world.

'He lives in the grounds of Plantation House which is the governor's residence with five other tortoises who are much younger than him.

I am still wondering how they identified that the black and white tortoise is the same tortoise as in the coloured photo based on photographs as evidence.