Cambrian fossils (aka loads of trilobites!) from western North America

Image: John Sibbick, Natural History Museum, London.

The Cambrian period was a time of some really bizarre looking critters and so many originated at this time (about 540 million years ago) that it is often referred to as the “Cambrian Explosion.” This period of the evolution of life saw some really bizarre body plans that transformed a simple environment dominated by cyanobacterial reefs and microbes into one of very highly ornamented and unusual critters. Douglas Fox describes this landscape of rapidly changing animals in his 2016 Nature article and gives us a good overview of the role that ocean water oxygen levels played in allowing for more complex life forms to develop and flourish.

Trilobites are a very common fossil to be found throughout the Paleozoic, but the Cambrian was where they dominated the seas that covered most of North America for many millions of years. Trilobites are arthropods and frequently molt their exoskeletons in order to grow. Most fossil remains of trilobites that we have today are fossilized exuviae, or the cast off exoskeletons instead of the actual animal itself, as the external shell is discarded to allow for the animal to grow.

Trilobites are an exceptional component of the history of life on our planet; indeed, they are among the most successful animals in the history of our planet. Join us for this second expedition to transcribe labels from Cambrian fossils of western North America. Our last expedition focused on plastotypes (plaster molds of type specimens from around the world) and these fossils here are the real deal. Many of these fossils are trilobites, but keep an eye out for our own Anomalocaris and other bizarre Cambrian fossils!

Copyright Nature Publishing Group, used with permission.