A fossilised bone dug up near Hastings 113 years ago has been recognised as a completely new family of dinosaur.
The specimen was left untouched for 113 years
The animal belongs to a general type of dinosaur called a sauropod - which was characterised by a large body, a long neck and a small head.
A PhD student from the University of Portsmouth stumbled upon the specimen while browsing through the shelves of London's Natural History Museum.
The work is to appear in the academic journal Palaeontology.
The fossil represents the dorsal vertebra (back bone) of a new family, genus and species of dinosaur now named Xenoposeidon proneneukus.
It lived about 140 million years ago, was about the size of an elephant and weighed 7.5 tonnes.
"It leapt out at me as being different," said Mike Taylor, a computer programmer who is studying sauropod vertebrae as part of his PhD at Portsmouth.
"It was unmistakably a dorsal vertebra from a sauropod, but it didn't look like any dorsal I'd ever seen before."
The bone has lain in the Natural History Museum since its discovery in the early 1890s in Ecclesbourne Glen, near Hastings, by fossil collector Philip James Rufford.
Odd one out
It was briefly described by the British palaeontologist Richard Lydekker but was then left untouched for the next 113 years.
Dr Paul Barrett, a researcher in palaeontology at the museum, said: "Dinosaur bones are being constantly reassessed and our collections still offer us lots of surprises."
Mr Taylor and fellow palaeontologist Dr Darren Naish know the preserved bone came from near the hip area of the dinosaur.
From this they made an informed guess about the size and shape of the animal and were able to establish why Xenoposeidon is not only a new genus and species, but probably a new family of dinosaur.
"The difference between this specimen and other sauropod vertebrae is sufficiently great that I concluded that it could not be placed in any existing species or genus," said Mr Taylor.
"In fact it can't be placed in any existing sauropod family."