A Haworth teenager has discovered a rare fossil while on holiday with his family in Dorset.

James Dickinson, 15, a pupil at Oakbank School, discovered a small lobster in a piece of shale when he was looking for fossils on a beach near Charmouth.

James’s mum, Bev Dickinson, said the area around Lyme Regis was well-known as a treasure trove for fossils and people often spent days out chipping away at rocks in search of unusual discoveries. James’s lobster fossil, which is the size of an adult thumb and is millions of years old, has certainly been described as unusual by geologists.

Bev said: “We took it to the Charmouth Heritage Coast Centre and Phil Davidson, a geological warden who had been working there for over 17 years, said he had never seen anything quite like it.”

Mr Davidson took the fossil to the Natural History Museum in London, where crustacean expert Dr Joe Collins identified it as Coleia brodei, a relative of both modern lobsters and prawns.

In a letter to the Dickinsons, Mr Davidson wrote: “Your specimen is unusual and it has been preserved in a strange way. The few lobsters found here in Dorset are usually preserved in hard limestone where their remains have been partially replaced by phosphate. Your specimen was preserved in soft shale, which has preserved portions of the original shell and has been partially crushed.”

The Dickinsons have now donated the fossil to the Natural History Museum collections and a geologist there has described it as a “stunning” find.

In a letter to the Dickinsons, a museum representative wrote: “This donation will enable your find to be preserved, researched and potentially published, making a real contribution to our knowledge.”

Bev, who works at Keighley Healthy Living Network, said: “James is thrilled he has found something so unusual and he was happy to have it donated to the Natural History Museum.

“We’ve always said we’d rather see it in their hands than on the shelf at home.”