Fossils found in Britain have been confirmed as belonging to the largest scorpion ever discovered, a giant predator that lived about 415 million years ago, according to a study published this month in the journal Palaeontology.

Researchers identified the animal as Praearcturus gigas, an extinct scorpion that grew to more than 1 meter (3.3 feet) in length and had pincers measuring about 16 centimeters (6.2 inches).

The findings help resolve a debate that has lasted more than 150 years. Although the first fossils were discovered in 1871, scientists long disagreed over whether the remains belonged to a scorpion or a large crustacean because the specimens were incomplete.

The new study compared the fossils with those of Eramoscorpius, a well-preserved ancient scorpion discovered in Canada, and found key anatomical features confirming that Praearcturus gigas was indeed a scorpion.

The fossils were found in the St Maughan's Sandstone Formation, which stretches across parts of Wales and western England and dates to the Early Devonian period, when life on land was still in its early stages.

Researchers said the giant arthropod lived tens of millions of years before other famous oversized invertebrates, such as the giant millipede Arthropleura and the dragonfly-like griffinflies that inhabited the Carboniferous period.

The study suggests Praearcturus gigas was among the earliest large predators to inhabit land. Scientists believe it may also have spent part of its life hunting in water, feeding on fish and other prey.

Researchers pointed to flap-like structures on the animal's body that resemble features found in lobsters and crabs, suggesting it may have been aquatic or amphibious.

The discovery provides new insight into a key period in Earth's history when plants and animals were beginning to establish themselves on land and ecosystems were still relatively simple.

Scientists said the lack of large competitors or predators at the time may have helped Praearcturus gigas grow to such enormous size.

Today, the world’s largest scorpions, found in the forests of India and Sri Lanka, typically grow to around 23 centimeters (9 inches).