Researchers establish oldest identified species of swimming jellyfish

The Royal Ontario Museum (ROM) declares the oldest swimming jellyfish within the fossil file with the newly named Burgessomedusa phasmiformis. These findings are introduced within the journal Proceedings of the Royal Society B.

Jellyfish belong to medusozoans, or animals producing medusae, and embrace right now’s field jellies, hydroids, stalked jellyfish and true jellyfish. Medusozoans are a part of one of many oldest teams of animals to have existed, referred to as Cnidaria, a gaggle which additionally consists of corals and sea anemones. Burgessomedusa unambiguously exhibits that giant, swimming jellyfish with a typical saucer or bell-shaped physique had already developed greater than 500 million years in the past.

Burgessomedusa fossils are exceptionally effectively preserved on the Burgess Shale contemplating jellyfish are roughly 95% composed of water. ROM holds near 200 specimens from which exceptional particulars of inner anatomy and tentacles will be noticed, with some specimens reaching greater than 20 centimeters in size. These particulars allow classifying Burgessomedusa as a medusozoan. By comparability with trendy jellyfish, Burgessomedusa would even have been able to free-swimming and the presence of tentacles would have enabled capturing sizeable prey.

“Though jellyfish and their kinfolk are regarded as one of many earliest animal teams to have developed, they’ve been remarkably onerous to pin down within the Cambrian fossil file. This discovery leaves little question they have been swimming about at the moment,” mentioned co-author Joe Moysiuk, a Ph.D. candidate in Ecology & Evolutionary Biology on the College of Toronto, who is predicated at ROM.

This examine, figuring out Burgessomedusa, is predicated on fossil specimens found on the Burgess Shale and largely discovered within the late Nineteen Eighties and Nineteen Nineties beneath former ROM Curator of Invertebrate Paleontology Desmond Collins. They present that the Cambrian meals chain was much more advanced than beforehand thought, and that predation was not restricted to massive swimming arthropods like Anomalocaris (see subject picture displaying Burgessomedusa and Anomalocaris preserved on the identical rock floor).

“Discovering such extremely delicate animals preserved in rock layers on prime of those mountains is such a wonderous discovery. Burgessomedusa provides to the complexity of Cambrian foodwebs, and like Anomalocaris which lived in the identical setting, these jellyfish have been environment friendly swimming predators,” mentioned co-author, Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Paleontology. “This provides yet one more exceptional lineage of animals that the Burgess Shale has preserved chronicling the evolution of life on Earth.”

Cnidarians have advanced life cycles with one or two physique types, a vase-shaped physique, referred to as a polyp, and in medusozoans, a bell or saucer-shaped physique, referred to as a medusa or jellyfish, which will be free-swimming or not. Whereas fossilized polyps are identified in ca. 560-million-year-old rocks, the origin of the free-swimming medusa or jellyfish isn’t effectively understood.

Fossils of any sort of jellyfish are extraordinarily uncommon. As a consequence, their evolutionary historical past is predicated on microscopic fossilized larval phases and the outcomes of molecular research from residing species (modeling of divergence instances of DNA sequences). Although some fossils of comb-jellies have additionally been discovered on the Burgess Shale and in different Cambrian deposits, and will superficially resemble medusozoan jellyfish from the phylum Cnidaria, comb-jellies are literally from a fairly separate phylum of animals referred to as Ctenophora. Earlier stories of Cambrian swimming jellyfish are reinterpreted as ctenophores.

The Burgess Shale fossil websites are situated inside Yoho and Kootenay Nationwide Parks and are managed by Parks Canada. Parks Canada is proud to work with main scientific researchers to develop data and understanding of this key interval of Earth historical past and to share these websites with the world by award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Website in 1980 on account of its excellent common worth and is now a part of the bigger Canadian Rocky Mountain Parks World Heritage Website.

Guests to ROM can see fossils of Burgessomedusa phasmiformis on show within the Burgess Shale part of the Willner Madge Gallery, Daybreak of Life.