A weird dragon-like beast that roamed Russia 250 million years ago has been unveiled by scientists.
It has been described as a prehistoric version of the Komodo lizard – and its head was truly enormous.
This housed powerful jaws and huge teeth shaped "like steak knives" that would have ripped prey to shreds.
An analysis of fossilised bones shows it belonged to a group of reptiles known as the erythrosuchids.
Named Garjainia, it was up to 10 feet long and is distantly related to today's birds, according to the journal Royal Society Open Science.
It lived in eastern Europe, South Africa, India and China when Earth's landmass was one large supercontinent called Pangaea.
Lead author Dr Richard Butler, of the University of Birmingham, said its remains were remarkably well preserved in 248 million year old rocks unearthed in Russia.
They included a partial skeleton and almost complete skull dug up at a site 45 miles from the city of Orenburg on the Ural River near the Kazakhstan border.
Dr Butler said: "Erythrosuchids are large, predatory meat-eating reptiles that lived shortly after the Permo-Triassic mass extinction, the largest ecological crisis in Earth history."
It happened 252 million years ago when huge volcanoes in Siberia erupted, making the oceans acidic.
More than 90 per cent of marine species and more than two-thirds of the animals living on land were wiped out.
Dr Butler said: "Erythrosuchids were superficially similar to Komodo dragons, that lived in the Triassic, 250 to 240 million years ago.
"One of the key results of this paper is we demonstrate numerically for the first time that erythrosuchids have hugely oversized heads relative to the rest of the body.
"Proportionately, their skulls are probably larger than any other group of living or fossil reptiles."
Erythrosuchids are evolutionarily close to the common ancestor of birds, dinosaurs and crocodilians. They were the top predators in their ecosystems.
Dr Butler said: "In appearance they looked a bit like a Komodo dragon – walking on four legs.
"But they had very large heads relative to their body, with powerful jaws and large, sharp, steak-knife-like teeth."
Garjainia was probably about three metres long (10ft), similar to a Komodo dragon, but other erythrosuchids got much larger.
Erythrosuchus, from South Africa, was over five metres (16.4ft) long, and had a head that was well over a metre (3ft 3in) in length.
Dr Butler said: "They lived just prior to the very first dinosaurs, so erythrosuchids and dinosaurs did not live alongside one another, as far as we know."
Following the Permo-Triassic mass extinction, terrestrial ecosystems witnessed the beginnings of a major evolutionary radiation of creatures known as archosauromorphs, he said.
This is a highly diverse group that includes dinosaurs, birds, pterosaurs and crocodilians. The erythrosuchids were among the earliest.
Dr Butler added: "These results provide support for the generalisation that the heads of erythrosuchids are disproportionately large relative to other groups of archosauromorphs.
"The enlarged heads were acquired coincident with increases in overall body size, and anatomical features related to carnivorous adaptations such as serrated teeth."
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