Scientists believe dinosaur dates back to 168m years ago during the middle Jurassic period

A complete stegosaurus fossil at the Natural History Museum in London. Remains of a new genus have been discovered in Morocco Photograph: John Stillwell/PA

A new species of one of the most recognisable types of dinosaur is also the oldest of its kind ever discovered, British scientists believe.

Remains of a stegosaurus, an armoured dinosaur instantly recognisable by the plate-like bones protruding from its spine and spikes on its tails, were studied by a team from the Natural History Museum and belong to a new genus that walked the earth around 168m years ago.

Despite the specimen including only a few vertebrae and an upper-arm bone, scientists concluded it was a new species and genus which dates to the middle Jurassic period – much earlier than most known stegosaurs.

The team, led by Dr Susannah Maidment, named it Adratiklit boulahfa, meaning “mountain lizard” in the Berber language.

Boulahfa is a reference to the area in the Middle Atlas mountains of Morocco where the specimen was found.

“The discovery of Adratiklit boulahfa is particularly exciting as we have dated it to the middle Jurassic,” said Maidment.