In the Media: Researchers discover the oldest species of swimming jellyfish

An artistic reconstruction shows a group of Burgessomedusa phasmiformis swimming 505 million years ago in the Cambrian sea, where it was believed to be one of the largest predators. Photo credit: Christian McCall.

Researchers with the Royal Ontario Museum (ROM) and the Faculty of Arts & Science’s Department of Ecology & Evolutionary Biology (EEB) have announced the discovery of the oldest swimming jellyfish in the fossil record in the journal Proceedings of the Royal Society B.

The 505-million-year-old jellyfish fossil was found in the Burgess Shale in B.C., a site rich in fossils that reveal the diversity of life during the Cambrian period. Given that jellyfish are 95 per cent water, it is a remarkable and rare fossil find.

“Although jellyfish and their relatives are thought to be one of the earliest animal groups to have evolved, they have been remarkably hard to pin down in the Cambrian fossil record,” says Joe Moysiuk, a PhD candidate in EEB who is based at the ROM and co-author of the announcement. “This discovery leaves no doubt they were swimming about at that time.”

“Finding such incredibly delicate animals preserved in rock layers on top of these mountains is such a wonderous discovery,” says co-author Jean-Bernard Caron, an associate professor in EEB who is also with the ROM. “This adds yet another remarkable lineage of animals that the Burgess Shale has preserved chronicling the evolution of life on Earth.”

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