450-million year old jellyfish ancestor looks like a flailing carwash tubeman
Popular Science...
Jellyfish are delicate, almost ghostly creatures. But under just the right circumstances, these spectral invertebrates can still tell stories long after their death. Not far from Quebec City, Canada marine paleontologists have discovered a new species of invertebrate that swayed in Paleozoic ocean currents over 450 million years ago. Paleocanna tentaculum may not look much like its living descendants, but according to a team of researchers writing in the Journal of Paleontology, the tubular polyp is more closely related to today’s jellyfish than its other ancient cousins.
The geological record contains far more examples of vertebrate fossils than invertebrates, or animals without a backbone. Given how few invertebrate samples there are in the fossil record, the study’s authors were particularly excited to finally examine a collection of unique specimens housed at Montreal’s Musée de paléontologie et de l’évolution (MPE). The specimens were first uncovered during a 2010 dig at the Upper Neuville Formation in the Saint Lawrence Lowlands—about 31 miles northeast of Quebec’s capital. A total of 15 limestone slabs were excavated by amateur fossil hunter John Iellamo and donated to the MPE.
“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,” study co-author and McGill University paleontologist Louis-Philippe Bateman said in a statement.
Bateman and colleagues tallied around 135 fossilized specimens before photographing and measuring 39 examples. They then compared their anatomy to 69 living and extinct species related to present-day jellyfish. The team soon realized many of the creatures were aligned in the same direction when they died.
“We think they were buried in place, or were not transported far before being buried,” explained study co-author and Université de Montréal palebiologist Greta Ramirez-Guerrero. “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.”
Unlike many jellyfish species, P. tentaculum wasn’t a free-floating organism. Instead, the tubular polyp likely anchored itself to the Paleozoic ocean floor, using its crown of tentacles to capture nearby prey. Despite its alien-like appearance, a taxonomic analysis shows the ancient creatures are much more closely related to living species like box jellies than they are to extinct, tube-dwelling animals. This places the animal much closer to present-day marine invertebrates than most other fossil polyps. Aside from its uniqueness, P. tentaculum serves as a valuable reminder that important paleontological discoveries aren’t always made in the most famous fossil formations.
“I’ve often caught myself saying that we have a less glamorous fossil record than places like British Columbia or Alberta,” said Bateman. “Discoveries like this one show that many things have yet to be discovered and described here.”
The post 450-million year old jellyfish ancestor looks like a flailing carwash tubeman appeared first on Popular Science.