The Cretaceous Period dinosaur, named Jakapil kaniukura, would have been well protected with rows of bony disk-shaped armour along its neck and back, and down to its tail, they said. It measured about 1.5m long and weighed only 4kg to 7kg, similar to an average house cat.

Its fossilised remains were dug up over the past decade near a dam in Patagonia in Rio Negro province’s La Buitrera paleontological zone. The scientists described Jakapil in a study published in the journal Scientific Reports.

The scientists said Jakapil marks a first-of-its-kind discovery of an armoured dinosaur from the Cretaceous in South America. It is part of the Thyreophoran dinosaur group that includes the likes of Stegosaurus, known for its bony back plates and spiky tail, and tank-like Ankylosaurus, covered in armour and wielding a club-like tail.

Lead paleontologist Sebastian Apesteguia and his colleagues found a partial skeleton of Jakapil, along with 15 tooth fragments featuring a leaf-like shape, similar to iguana teeth.

Jakapil resembles a primitive form of Thyreophoran that lived much earlier, making it a surprise that it dated from the Cretaceous. Apesteguia said never before has such a Thyreophoran been dug up anywhere in the southern hemisphere.

(Reporting by Miguel Lo Bianco.)