Scientists discovered a 508 million-year-old lobster relative that had appendages equipped with three claws and a terrifying set of teeth.

The species, dubbed Yawunik kootenayi, swam the waters of what is now Canada 250 million years before dinosaurs first appeared, the University of Toronto reported. The ancient creature is also related to butterflies and spiders.

"This creature is expanding our perspective on the anatomy and predatory habits of the first arthropods, the group to which spiders and lobsters belong," said Cedric Aria, a PhD candidate in U of T's Department of Ecology & Evolutionary Biology and lead author of the resulting study published this week in Palaeontology. "It has the signature features of an arthropod with its external skeleton, segmented body and jointed appendages, but lacks certain advanced traits present in groups that survived until the present day. We say that it belongs to the 'stem' of arthropods."

The fossils, discovered in the Canadian Burgess Shale fossil deposit, reveal the animal was able to move its frontal appendages backwards and forwards and retract them under its body when swimming. 

"Unlike insects or crustaceans, Yawunik did not possess additional appendages in the head that were specifically modified to process food," Aria said. "Evolution resulted here in a combination of adaptations onto the frontal-most appendage of this creature, maybe because such modifications were easier to acquire.

The researchers believe Yawunik was at the top of the food chain and played an important role in the ancient ecosystem. The scientists named it after the local mythological marine creature "Yawunik" as an homage to the Ktunaxa People, who have long inhabited the Kootenay area where the fossils were found.

"Yawunik is a central figure in the Ktunaxa creation story, and, as such, is a vital part of Ktunaxa oral history," said Donald Sam, Ktunaxa Nation Council Director of Traditional Knowledge and Language. "I am ecstatic that the research team recognizes how important our history is in our territory, and chose to honour the Ktunaxa through this amazing discovery."