Carnotaurus
It makes up for its deficiencies with a powerful tail. Creative Commons

The Carnotaurus, one of the fiercest predators measuring up to 2.9 tons, may have dinky arms, but it's probably the fastest dinosaur to ever roam our planet.

Recent studies showed how cousin T. rex may have been larger than we thought, and now research tells us is capable of running up to 50 kilometers an hour. Students at the University Alberta examined the tail of the Carnotaurus and argues that larger tail muscles produced faster runners.

The dinosaur is a native to South America in the Jurassic and Cretaceous periods.

The Carnotaurus's tail is believed to be the most powerful of all dinosaurs. In fact, it may even be faster than others like the rhinoceros at a charging speed. This made the Carnotaurus a fierce hunter at the top of the prehistoric food chain.

Just like the T. rex's size exceeded our expectations and predictions, the Carnotaurus may have been a much deadlier predator than we thought.