Ancient Lobster-Like Predator Discovered in Canada

An ancient and unusual lobster-like predator was recently discovered in Canada, in a fossil treasure trove dating as far back as 508 million years ago - well before the first dinosaurs walked the Earth, according to a new study.

The new species, called Yawunik kootenayi, is a marine creature with two pairs of eyes and prominent grasping appendages that resemble the antennae of modern beetles or shrimps. What's more, each of these appendages boasted three long claws with rows of sharp teeth used for catching prey.

But despite its bizarre appearance, Yawunik is actually the long-extinct ancestor of a diverse range of modern species, including today's butterflies, spiders, and lobsters.

"This creature is expanding our perspective on the anatomy and predatory habits of the first arthropods, the group to which spiders and lobsters belong," lead author Cedric Aria, from the University of Toronto, said in a press release. "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."

But with its extremely large appendages, how was Yawunik able to swim under water? The study presents evidence that it could move its frontal appendages backward and forward, spreading them out during an attack and then retracting them under its body when swimming.

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

"We know that the larvae of certain crustaceans can use their antennae to both swim and gather food. But a large active predator such as a mantis shrimp has its sensory and grasping functions split up between appendages," Aria explained. "Yawunik and its relatives tell us about the condition existing before such a division of tasks among parts of the organism took place."

To better understand this bizarre species, discovered in the Marble Canyon site of British Columbia, the researchers used so-called "elemental mapping" - which involves detecting the atomic composition of the fossil and the surrounding sediment. And because Yawunik was a predator in the region so long ago, it played an important part in the food chain and overall ecosystem. This study helps provide some insight into the dawn of animals.

It would be more than 250 million more years before the first dinosaurs would arrive, and until then predators like Yawunik dominated the Earth.

The findings were published in the journal Palaeontology.

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