A palaeontologist lies down alongside the thigh bone of the newly discovered dinosaur Museo Paleontologico Egidio Feruglio

Palaeontologists in Argentina have uncovered the fossilised remains of the largest dinosaur yet discovered.

Scientists believe that the remains are 90 million years old, based on the age of the rocks in which the bones were found, news website panarmenian.net reported.

The fossil was discovered in the Patagonia region of southern Argentina.

Based on the length of the thigh bone, scientists calculate that the creature was 40m (130ft) long and 20m (65ft) tall, and weighed at least 77 tonnes.

Dinosaur site
The excavation site in Patagonia Museo Paleontologico Egidio Feruglio

"Given the size of these bones, which surpass any of the previously known giant animals, the new dinosaur is the largest animal known that walked on Earth," researchers from the Museum of Palaeontology Egidio Feruglio told BBC News.

"Its length, from its head to the tip of its tail, was 40m. Standing with its neck up, it was about 20m high - equal to a seven-storey building."

According to the website, the fossil is a new species of the long-necked herbivore (vegetarian) group Titanosaur and dates to the late Cretaceous period.

The fossil was discovered by a farmer in the deserts of La Flecha, Patagonia. A team of palaeontologists excavated 150 fossilised bones, all in remarkable condition.