New lobster-like predator found in 508 million-year-old fossil-rich site

Mar 27, 2015

Credit: Jean-Bernard Caron/Royal Ontario Museum


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

The fossil was identified by an international team led by palaeontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) in Toronto, as well as Pomona College in California. It is the first new species to be described from the Marble Canyon site, part of the renowned Canadian Burgess Shale fossil deposit.

Yawunik had evolved long frontal appendages that resemble the antennae of modern beetles or shrimps, though these appendages were composed of three long claws, two of which bore opposing rows of teeth that helped the animal catch its prey.

“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.”

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12 comments on “New lobster-like predator found in 508 million-year-old fossil-rich site

  • When I saw this discussion posted, at first I thought it might be this one from a slightly later period!

    .Scientists have discovered a bizarre human-sized lobster ancestor that lived 480 million years ago.

    The monster used spiny “limbs” on its head to sift food from the ocean.

    It also had pairs of fins along both sides of its 2m-long body, which are precursors of the double limbs seen in many of its living relatives.

    This adds to our picture of how modern “arthropods” developed – a group of animals that includes crustaceans, spiders and insects.

    An unusually well-preserved fossil from Morocco was the key to the discovery.

    .Reported in Nature, the research was carried out by scientists at Oxford and Yale Universities.

    The fossil itself was first found by fossil hunter Mohamed Ben Moula and is named in his honour: Aegirocassis benmoulae. The first part of the name refers to a giant Norse sea god (Aegir) and the Latin for helmet (cassis).

    3D preservation

    The beast belongs to a very early family of sea creatures called “anomalocaridids”, which first appeared 520 million years ago during the Cambrian period. This new species, living some 40 million years later in the early Ordovician period, was probably among the last of its kind.

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  • Some day someone is going to make a computer app that displays the tree of life. You can zoom in on any part of it and see fossils, reconstructions or photos of the various species, maybe even video, along with commentary about how this branch fits into the overall picture, what its characteristics are.

    It would be like the Wikipedia of biology.

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  • Roedy. I can’t come up with an animation yet, but there are a number of diagrams that graphically display a simple version of what you seek.

    Can I recommend a documentary series. 3 episodes. Your Inner Fish. Your Inner Reptile and Your Inner Ape. Very good science that contained lots of animations on the evolution of life on earth.

    I had a quick look on YouTube and found a promo for episode one. I found it informative.

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  • anomalocaris


    first time I perused a book on ancient sea critters was jarring. Amazing to think they inhabited Earth, albeit from long, long ago. Truth is stranger than fiction.

    *wonderfully strange specimens currently lurk way down below the ocean – do research sub. lights negatively affect them.

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