Department of Natural History (Palaeobiology), Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
Simon Conway Morris
Département de sciences biologiques, Université de Montréal, Pavillon Marie-Victorin, Montréal QC H2V 2S9, Canada
Christopher B. Cameron
All authors contributed to write the main paper and commented on the manuscript at all stages. J.-B.C. conducted the observations and photography of specimens, prepared figures and wrote the Supplementary Information.
Competing financial interests
The authors declare no competing financial interests.