In 2005, workers mining for opals in Australia stumbled across a different treasure: a 25-centimeter-long (10-inch-long) dinosaur claw. 

Now, 10 years later, scientists have reconstructed the dinosaur using its discovered remains, which includes part of a forearm, a metatarsal, a rib, parts of a hip and a lower leg. The final beast is around 7 meters (23 feet) long. This brand new type of dinosaur is the largest ever carnivorous dinosaur found in Australia – the previous record-holder was the Australovenator, which was 5 meters long (16.5 feet long).

Dubbed the "Lightning Claw" by its founders, the dinosaur was christened this electrifying name because its claw was discovered at a mine in Lightning Ridge. The researchers predict the dinosaur was roaming Australia nearly 110 million years ago, and that its territory was around the floodplains of the ancient supercontinent of Gondwana.

You can find the results published in Gondwana Research.

“When I first saw the bones I knew they were important and unique but it’s taken until now to do all our comparisons and find out this is a new dinosaur to science,” commented Dr. Phil Bell from the University of New England to Guardian Australia.

^{Image in text: Continental drift of Pangea to Laurasia and Gondwana to our Earth now. Designua/Shutterstock.}

Its ferocious claws are a bit bigger than the height of an average house cat (24 centimeters / 9.5 inches). These terrifying killing tools belie the dinosaur's possible hunting technique.

“It was obviously a predator but the key thing about this guy is the giant claws on its hands," said Bell. "These claws compensate for a rather dainty skull and slender jaws, which are unlike the giant skull of a T-Rex, which had a bone-crushing bite.

“This dinosaur probably ran down its prey and used its arms like grappling hooks. Its mouth was simply to tear off small pieces of meat.”

It turns out that this as yet unnamed dinosaur may not have even survived until the mass dinosaur extinction event 65 million years ago. The researchers think that it became extinct three or four million years before that. 

“We don’t know what else is out there, whether it faced competition or its environment changed,” Bell said. “It certainly would’ve been replaced by something equally fearsome and equally large, we just haven’t found it yet.”

Australia's ancient dinosaur population is sparse compared to other areas of the world. They only have 17 well-defined species, except most of these are conclusions drawn from fossil fragments. Even though Bell is apprehensive to announce this dinosaur as a new species, it's still an exciting addition to the dinosaur inventory.

“We get tantalizing glimpses into ancient ecosystems but there’s certainly new discoveries to be found,” Bell said. “Having a big scary predator dinosaur on your desk is certainly quite nice.”

[H/T: Guardian]

Edit: We stated that the Lightning Claw was the largest dinosaur. It is infact the largest carnivorous dinosaur. A larger Australian dinosaur, at eight or nine meters long, was the Muttaburrasaurus, but they only ate veggies.