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Weird wonders lived past the Cambrian
A 'Burgess Shale-type' fauna, rich in fossils of soft-bodied creatures, has been found in the Lower and Upper Fezouata formations of Morocco, dating from about 480-472 million years ago during the Early Ordovician. The Fezouata biota is a link between Burgess Shale communities of the Middle Cambrian and the Great Ordovician Biodiversification Event, previously represented mostly by 'shelly' fossils. The cover shows a marrellomorph arthropod from the Fezouata biota. Cover photo by P. Van Roy.
Moroccan fossils show that strange early animals were no flash in the pan.
Nicola Jones
The fossils contain the earliest known cheloniellids, a distant relative of crustaceans and insects.
P. Van Roy
The batch of more than 1,500 specimens, reported in Nature this week 1, sheds light on the Early Ordovician period, 488 million to 471 million years ago, at the start of a huge expansion in the diversity of living things. In most Ordovician fossils, only the hard parts of animals, such as shells, are preserved. "We're missing a huge chunk of the data," says Derek Briggs of Yale University in Connecticut, a co-author on the paper. The Moroccan fossils, which show soft-bodied animals, fill in some of the gaps.
The team has catalogued at least 50 types of soft-bodied animals, including a mix of creatures previously seen only in earlier or later rocks. At a species level they're all brand new, says co-author Peter Van Roy, also at Yale. But one step up the family tree, about two-thirds of them are the same as found in the earlier Cambrian.
The fossils were found at 40 sites in the Draa Valley, in the desert region of southern Morocco. The spread of locations means that the finds give a panorama of this crucial period in evolution, says palaeontologist Graham Young of the Manitoba Museum in Winnipeg, Canada, who also works on Ordovician fossils. "It's like getting a photo album rather than just a snapshot."
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