The so-called Cambrian explosion is commonly labeled as the time in Earth’s history when animal body plans suddenly appear.

Most studies suggest that this event occurred between 541 million and 530 million years ago at the beginning of the Cambrian period.

“The Cambrian explosion is a unique period in the history of life that poses many unanswered questions,” said Dr. Olmo Miguez Salas from the Universitat Barcelona and Dr. Zekun Wang of the Natural History Museum, London.