Canadian fossil collectors from the Peace Region Paleontology Research Center in Tumbler Ridge, British Columbia, have discovered fossils of a stunning 240 million-year-old species of coelacanth.
The fast-swimming coelacanth Rebellatrix chasing smaller species of fishes in the Early Triassic ocean west of Pangaea (Michael Skrepnick)
Coelacanths are iconic fishes, well-known as living fossils. The group was thought to have died out with the dinosaurs until a living one was caught in 1938 off the coast of South Africa, sending shock waves through the scientific world.
The newly discovered species, described by two University of Alberta scientists in the recent issue of the Journal of Vertebrate Paleontology, was a 3-foot long fish with a massive symmetrical forked tail quite unlike the tails of any other living or fossil coelacanths.
The fossils were discovered on rocky slopes in the Hart Ranges of Wapiti Lake Provincial Park in British Columbia, which at the time the fish was alive was off the western coast of the supercontinent Pangaea.
The species, named Rebellatrix divaricerca, meaning the “rebel coelacanth”, represents the first major change in body shape for the coelacanth group in more than 70 million years. The structure of this new fish is so unusual that it has been put in its own family.
“The reason for its unusual shape comes down to two possibilities,” said lead author Dr. Andrew Wendruff. “Either the fossil record of coelacanths is vastly undiscovered and there are others like it yet to be found, or this was a specific response following the Earth’s greatest mass-extinction event at the end of the Permian , as coelacanths evolved to fill a vacant niche unoccupied by other predatory fishes.”
“Both the shape and the stiffness of the tail fin are unique amongst coelacanths,” explained Dr. Mark Wilson, co-author of the study. “Similar tail fins occur today in fast swimming predatory fishes such as tuna or barracuda, strongly suggesting that Rebellatrix was an active predator capable of fast bursts of swimming and high-speed cruising to search for and catch other fishes living in the ancient sea.”
“This is an amazing discovery which overturns the age old image of coelacanths as slow moving fishes and shows the resilience of the group to come back in true fighting form after surviving the world’s most devastating mass extinction event,” said Dr. John Long of the Natural History Museum of LA County, an expert in fossil fishes who was not involved in the study.
Sci-News.com has also recently reported the discovery of the oldest known coelacanth species from the Early Devonian of Yunnan, China.
