Burgess Shale-like fossils live on

The Burgess Shale of British Columbia famously contains a remarkable variety of fossils of softbodied creatures from the Middle Cambrian of around 510 million years ago, offering a window on early animal life in the sea. Similar faunas are now known from localities as far apart as China and Greenland, but it was beginning to seem that such faunas had died out by the end of the Middle Cambrian. But no. A ‘Burgess Shale-type’ fauna has been found in the Lower and Upper Fezouata formations of Morocco, dating from about 480–472 million years ago in the Early Ordovician. Creatures of this type clearly persisted beyond the Cambrian — a persistence with as much to do with the chances of preserving soft-bodied fossils as with extinction and survival. The Fezouata biota is a link between Burgess Shale communities and the early stages of the Great Ordovician Biodiversification Event, one of the most dramatic episodes in the history of marine life previously represented almost exclusively by ‘shelly’ fossils. The cover shows a marrellomorph arthropod — probably of the genus Furca — from the Fezouata biota. [Letter p. 215] .