Yawunik kootenayi was a fierce hunter that made its way through Earth's waters 500 million years ago, long before the age of dinosaurs. The ancient creature resembled a lobster, sporting six claws and guided by two pairs of eyes.
The species is named for a mythological figure from the oral traditions of the Ktunaxa people, who live near the site where Yawunik fossils were discovered. Legend tells of a marine hunter who caused such terror that a band of animals came together to kill the terrible beast. The real-life extinct creature was however only six inches in length.
Paleontologists from the University of Toronto and the Royal Ontario Museum (ROM) made the discovery in the Marble Canyon in Canada, in cooperation with researchers from Pomona College in California.
"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," said Cédric Aria from the University of Toronto.
Three claws protruded from the front of the creature — two of which held opposing sets of teeth, designed to grab onto prey. The appendages were likely capable of moving both backward and forward, and could be "tucked in" under the animal when not in use.
Modern crustaceans divide functions for sensing and grasping food into separate appendages. The Yawunik carried out those tasks utilizing the same antenna-like structures.
The species lived during the Cambrian period, an era that witnessed the rise of major animal groups and complex ecosystems.
The Marble Canyon fossil beds were first discovered in 2012, and paleontologists quickly learned that the area is one of the richest grounds for fossils in the world. Yawunik is one of the most common species found at the site, with the first specimen discovered on the second day of exploration. The species has however not been described in detail until now.
Yawunik is an example of leanchoiliid arthropods, which include shrimp, lobsters, ants and horseshoe crabs. The newly discovered creature is an ancestor not just to lobsters, but also butterflies and spiders.
Arthropods are one of the most prolific of all animal phylums, making up 80 percent of the known species on Earth. Most of these animals feature a hard exoskeleton, with highly specialized appendages to carry out single tasks, unlike the multi-use limbs of the newly described marine hunter. Biologists are still uncertain how arthropods evolved into their current forms, although this discovery may shed light on that development.
The discovery of the species and analysis of its ancient body plan was detailed in the journal Paleontology.