New lobster-like predator found at 500 mn-year-old site

What do butterflies, spiders and lobsters have in common? They are all surviving relatives of a newly-identified prehistoric species called Yawunik kootenayi.

An international team of palaeontologists recently found fossil remains of Yawunik at the Marble Canyon site in British Columbia's Kootenay National Park.

Researchers said Yawunik was a marine creature with two pairs of eyes and prominent grasping appendages that lived as much as 508 million years ago - more than 250 million years before the first dinosaur.

"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 lead author Cedric Aria from the University of Toronto.

Yawunik had evolved long frontal appendages that resemble the antennae of modern beetles or shrimps.

These appendages were composed of three long claws, two of which bore opposing rows of teeth that helped the animal catch its prey, the researchers described in a paper 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," Aria explained.

Researchers said Yawunik was capable of moving its frontal appendages backward and forward, spreading them out during an attack and then retracting them under its body when swimming.

Coupled with the long, sensing whip-like flagella extending from the tip of the claws, this makes the frontal appendages of the animal some of the most versatile and complex in all known arthropods.

"Unlike insects or crustaceans, Yawunik did not possess additional appendages in the head that were specifically modified to process food," said Aria.