A British pensioner got a shock of his life when he came to know that an odd-shaped rock he had with him for the past nine years was actually a dinosaur fossil from 135 million years ago.<br/><br/>John Ruggles, 75, first found the priceless plesiosaur fossil when he dismantled the garden feature nine years ago.<br/><br/>But while the unusual stone caught his eye, he assumed it was just an "odd shaped" rock and moved it around his garden as an ornament, eventually leaving it in his greenhouse.<br/><br/>Out of sheer curiosity, he decided last December to send the 12inch by 8 inch rock to his local museum, which identified the rock as a bone of a plesiosaur — a type of carnivorous aquatic reptile that resembled a snake threaded through the shell of a turtle.<br/><br/>The ocean dweller could grow to lengths of up to 40ft and is known to have lived from the late Triassic period through the Jurassic period and into the late Cretaceous period.<br/><br/>Experts described the fossil as "very rare", as it has been so well preserved that blood vessels are still visible in it.<br/><br/>Ruggles, a retired British Gas meter reader who lives in Downham Market, Norfolk, said it was lucky he never threw it away and has decided to donate it to the Museum.<br/>