Paleontologists examining limestone slabs from a site northeast of Quebec City have identified a previously unknown species of jellyfish ancestor that lived 450 million years ago, when the area lay beneath a shallow sea.

The species, named Paleocanna tentaculum, is a tube-shaped polyp with a ring of tentacles that represents one of only a handful of soft-bodied organisms from its era ever recovered from the fossil record. The discovery, published in the Journal of Paleontology, challenges common assumptions about where significant paleontological finds occur in Canada.

"I've often caught myself saying that we have a less glamorous fossil record than places like British Columbia or Alberta," said Louis-Philippe Bateman, a graduate student in McGill University's Department of Biology and study co-author. "Discoveries like this one show that many things have yet to be discovered and described here."

The Preservation Problem

The rarity of Paleocanna tentaculum stems from a fundamental challenge in paleontology: soft tissue almost never survives long enough to fossilize. Unlike organisms with shells, bones, or exoskeletons, jellyfish and their relatives typically decompose completely within days or weeks of death.

"Soft-bodied organisms do not preserve as well as hard-bodied organisms, usually making any soft-bodied fossil more valuable to understanding the history of life," Bateman explained.

The research team examined fifteen slabs of shaly limestone containing approximately 135 specimens, measuring and photographing 39 of them. The fossils came from the Upper Neuville Formation near Saint-Joachim, about 50 kilometers northeast of Quebec City—a location that Christopher Cameron, professor of biology at Université de Montréal and study co-author, describes as "among the most species-rich fossil localities on the planet" for Ordovician-period fossils.

Buried Alive on the Seafloor

The exceptional preservation appears to have resulted from a catastrophic burial event. Lead author Greta Ramirez-Guerrero, a PhD candidate at Université de Montréal, noted that many specimens are aligned in the same direction, suggesting they were rapidly covered where they lived or shortly after being transported.

"This rapid burial, combined with low-oxygen conditions in the surrounding environment, slowed decay and helped preserve the animals before the sediment turned to rock," Ramirez-Guerrero said.

The team believes fine mud suddenly blanketed the seafloor, entombing the organisms before scavengers could consume them. The low-oxygen environment then prevented bacterial decay, allowing the soft tissues to leave impressions in the sediment as it lithified into limestone over millions of years.

Connecting Ancient and Modern

To classify their find, researchers compared the physical features of the fossils with 69 other fossil and living jellyfish-related species. Their analysis revealed that Paleocanna tentaculum is more closely related to modern jellyfish than to other ancient relatives, making it a basal medusozoan—an early branch of the evolutionary tree that would eventually produce the jellyfish we see today.

The specimens are now housed at the Musée de paléontologie et de l'évolution (MPE) in Montreal, where they will be available for further study. The museum's founder, Mario Cournoyer, emphasized the role of amateur paleontologists in the discovery.

"We must pay tribute to John Iellamo, a reputed amateur fossil collector and member of our museum, who found these fossils in 2010 and subsequently donated them to the MPE," Cournoyer said. "He was able to recognize the scientific importance of these fossils and made them available for research. Without him, we would not be talking about this new species."

More Discoveries Expected

The Saint-Joachim site may yield additional finds. Bateman noted that localities producing well-preserved soft-bodied fossils tend to be productive for years or even decades after initial discovery.

"Once you find them, these kinds of sites tend to keep producing spectacular new material and species for many years, so I'm expecting many more new interesting discoveries to come," he said.

The Ordovician period, spanning roughly 485 to 444 million years ago, saw explosive diversification of marine life. Quebec's fossil record from this era provides a window into ecosystems that existed long before the first plants colonized land or the first vertebrates crawled from the sea.

The research was funded by the Natural Sciences and Engineering Research Council of Canada and the Fonds de Recherche du Québec. The study, "Thecate stem medusozoan polyp from the Upper Ordovician of Québec," includes contributions from Huda Alghaled in addition to the researchers mentioned above.