|Treptichnus pedum, the trace fossil which defines the base of the Cambrian|
|One of the remarkable fossils from Fezouata, |
specifically of a marellomorph arthopod
Over 160 genera have been recorded from the locality, including a large number of lobopodians - the group of arthropods which contained within it the majority of the Cambrian oddities, including Hallucigenia and Anomalocaris. They show that the biotic legacy of the Cambrian Explosion extended well into the Ordovician, which itself is thought to have overseen its own evolutionary radiation - the Great Ordovician Biodiversification Event. 'There is much more to learn from the Fezouata' said Professor Briggs. 'Why do we not see more assemblages like this in the Ordovician? What ecological changes happened at the Cambro-Ordovician interval? Are the Cambrian Explosion and the Great Ordovician Biodiversification Event separate, or phases of the same event?'
|Aegirocassis benmoulae was an Ordovician |
arthropod which was larger than a human
In addition to Cambrian hanger-ons, other fossils have redefined the evolutionary histories of other organisms besides. 'Horseshoe crabs, for example, turn out to be at least 20 million years older than we thought. The formation demonstrates how important exceptionally preserved fossils are to our understanding of major evolutionary events in deep time' said Peter Van Roy, also of Yale, who first recognised the scientific importance of the Fezouata fauna. The Kootenay and Maotianshan sites have yielded remarkable finds from the Cambrian which have added to the wealth of knowledge originally collected at the Burgess Shale. Fezouata, however, demonstrates that we should also examine the Ordovician to gain a fuller picture of the true extent of the Cambrian Explosion.