The Royal Ontario Museum (ROM) declares the oldest swimming jellyfish within the fossil report 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 embody in the present day’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 bunch which additionally consists of corals and sea anemones. Burgessomedusa unambiguously exhibits that enormous, 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 nicely preserved on the Burgess Shale contemplating jellyfish are roughly 95% composed of water. ROM holds near 200 specimens from which outstanding particulars of inside anatomy and tentacles may be noticed, with some specimens reaching greater than 20 centimeters in size. These particulars allow classifying Burgessomedusa as a medusozoan. By comparability with fashionable 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 relations are considered one of many earliest animal teams to have developed, they’ve been remarkably exhausting to pin down within the Cambrian fossil report. This discovery leaves little question they had 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 relies at ROM.
This examine, figuring out Burgessomedusa, relies on fossil specimens found on the Burgess Shale and principally discovered within the late Nineteen Eighties and Nineties underneath 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 giant swimming arthropods like Anomalocaris (see area picture displaying Burgessomedusa and Anomalocaris preserved on the identical rock floor).
“Discovering such extremely delicate animals preserved in rock layers on high of those mountains is such a wonderous discovery. Burgessomedusa provides to the complexity of Cambrian foodwebs, and like Anomalocaris which lived in the identical surroundings, these jellyfish had been environment friendly swimming predators,” mentioned co-author, Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Paleontology. “This provides one more outstanding 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 varieties, 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 may 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 shouldn’t be nicely understood.
Fossils of any kind of jellyfish are extraordinarily uncommon. As a consequence, their evolutionary historical past relies on microscopic fossilized larval levels 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 should superficially resemble medusozoan jellyfish from the phylum Cnidaria, comb-jellies are literally from a fairly separate phylum of animals referred to as Ctenophora. Earlier experiences of Cambrian swimming jellyfish are reinterpreted as ctenophores.
The Burgess Shale fossil websites are positioned inside Yoho and Kootenay Nationwide Parks and are managed by Parks Canada. Parks Canada is proud to work with main scientific researchers to broaden data and understanding of this key interval of Earth historical past and to share these websites with the world by way of award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Website in 1980 as a result 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.
A macroscopic free-swimming medusa from the center Cambrian Burgess Shale, Proceedings of the Royal Society B: Organic Sciences (2023). DOI: 10.1098/rspb.2022.2490. royalsocietypublishing.org/doi … .1098/rspb.2022.2490
Royal Ontario Museum
Researchers determine oldest identified species of swimming jellyfish (2023, August 1)
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