Forget Velociraptors! Terrifying big brother of Megaraptor dinosaurs grew more than 21 feet long and had 3-inch serrated teeth Read more: http://www.dailymail.co.uk/sciencetech/article-3699640/Forget-Velociraptors-Terrifying-big-brother-Megaraptor-dinosaurs-grew-21-feet-long-3-inch-serrated-teeth.

The new dinosaur, which had serrated teeth up to three inches long (8.2cm), has been named Murusraptor barrosaensis, after the Sierra Barrosa area of northwest Patagonia where it was found.

Like its relatives it would have been a theropod and likely had a large sickle-shaped retractable claws on each of its legs.

But the researchers found it had distinctive facital features not seen in Megaraptor and its other relatives Aerosteon and Orkoraptor.

They said the creature also had unusually elongated hip bones that makes it more slender than Megaraptor.

Dr Rodolfo Coria, a palaeontologist at the Bernardino Rivadavia Natural Sciences Museum, in Buenos Aires, and Dr Philip Currie, a palaeontologist at the University of Alberta, Canada, said the fossil they found probably belonged to a juvenile.

Yet despite being immature it was already almost 21 feet long - already as large as many Megaraptor that have been discovered.