LISBON, Portugal- Palaeontologists in Portugal have unearthed the fossilised skeleton of what could be the largest dinosaur ever found in Europe.

The remains are thought to be those of a sauropod, a herbivorous dinosaur 12 metres (39 feet) tall and 25 metres long that roamed the Earth around 150 million years ago.

"It's one of the biggest specimens discovered in Europe, perhaps in the world," palaeontologist Elisabete Malafaia, from the Faculty of Sciences at Lisbon University, told AFP on Monday.

The bones were uncovered by Portuguese and Spanish scientists in the garden of a house near Pombal in central Portugal at the beginning of August.

Among the bones collected, they found the remains of a rib about three metres long, Malafaia said.

Fossil fragments were first noticed at the site in 2017, when the owner was digging up his garden to make way for an extension.

He contacted palaeontologists, who unearthed part of the dinosaur skeleton earlier this month and have been examining it ever since.

Sauropods have characteristically long necks and tails and are among the largest animals to have ever lived.

The fossils discovered at the Monte Agudo site in Pombal are thought to be those of a brachiosaurid who lived during the Upper Jurassic period.

The fact that the vertebrae and ribs were found at the same location and in the position they would have been in the dinosaur's anatomy is "relatively rare", Malafaia said.

The team may conduct more digs in the coming months at the site and in the surrounding area.