What weighs as much as 14 African elephants and is longer than four London buses placed end-to-end? The largest creature ever to have walked the Earth, according to scientists who have been examining newly discovered dinosaur remains in Argentina.

A farm worker stumbled across the gigantic fossilised bones near La Flecha in the Patagonian desert. Now palaeontologists have announced their conclusions.

They measured the length and circumference of the largest femur (thigh bone), to calculate that the animal weighed 77 tonnes. That makes it the biggest dinosaur yet, seven tonnes heavier than the last to hold the record, Argentinosaurus, also discovered in Argentina, in 1987.

The latest fossils were unearthed by a team from Argentina’s Museum of Paleontology Egidio Feruglio, led by Dr Jose Luis Carballido and Dr Diego Pol.

“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,” the scientists told the BBC. “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.”

They excavated the partial skeletons of seven individual dinosaurs – about 150 bones in total – and said they were all in “remarkable condition”.

The team believes the bones come from a new species of titanosaur, a sub-group of the long-necked herbivorous sauropods that roamed the world’s forests about 100 million years ago during what is known as the Late Cretaceous period. Argentinosaurus is from the same group, as is the smaller diplodocus.

But the latest discovery has yet to be given a name. “It will be named describing its magnificence and in honour to both the region and the farm owners who alerted us about the discovery,” the research team said.

Because complete skeletons have not been discovered, the actual size of the animal can only be estimated.

Argentinosaurus was first thought to weigh 100 tonnes but the figure was later revised down to about 70 tonnes – making it smaller than the latest discovery. This time the scientists are more confident of the size owing to the large number of bones found.

But Dr Paul Barrett, a dinosaur expert from London’s Natural History Museum, noted: “There are a number of similarly sized big sauropod thigh bones out there.

“Without knowing more about this current find it’s difficult to be sure. One problem with assessing the weight of both Argentinosaurus and this new discovery is that they’re both based on very fragmentary specimens – no complete skeleton is known, which means the animal’s proportions and overall shape are conjectural.”

Questions for debate and discussion

  1. What does an archaeologist do? What about a palaeontologist?
  2. What can the discovery of an extremely large dinosaur tell us about the past?
  3. Is there anything that this discovery can teach us about the present?
  4. Many books and films have been written about dinosaurs. Why do you think dinosaur fiction is so popular?

Resources – TES Connect

Earth’s timeline activity
This memorable on-your-feet activity introduces the vast nature of our planet’s history using toilet roll as a prop.

What killed the dinosaurs?
Students can become prehistoric reporters with this lesson about the extinction of the dinosaurs.

Let’s go on a dinosaur adventure!
Take pupils on a prehistoric adventure with this great stimulus for creative writing.

Bird or dinosaur?
Hank Green of SciShow explains the truth behind what is and isn’t a dinosaur.