Researchers have discovered a new species of ancient fish with hooked front fangs that made them a fearsome and effective predator.
A paper published in the Journal of Vertebrate Paleontology this week says the long, curved jaw of the animal sheds light on how fish were evolving smaller, front teeth that acted like fishing hooks, about 350 million years ago.
Meanwhile, the centimetre-long back fangs were used to chew the catch before digestion into a body that may have been almost a metre long. They hunted for prey in the inland waters of Nova Scotia, in what was likely a vast inland lake.
Lead author Conrad Wilson, a doctoral candidate in paleontology at Carleton University in Ottawa, said in an interview Friday that the fish has been named Sphyragnathus tyche, with the first phrase meaning “hammer jaw.”
“I would say it’s a fairly fearsome looking fish. If its mouth is open, you would see those fangs in the jaw,” he said
But the fossil is also significant for the clues it offers to the evolution of ray-finned fish — a huge and diverse vertebrate group that occupies a wide range of aquatic and semi-aquatic environments around the globe.
“These fish were the last major group of vertebrates to be identified and we still have big gaps in our knowledge about their early evolution,” Wilson said, who published his paper with Chris Mansky, a fossil researcher at the Blue Beach Fossil Museum in Hantsport, N.S., and Jason Anderson, a professor of anatomy in the veterinary faculty at the University of Calgary.
“The fossils are telling us about what the fish existing right after a mass extinction looked like,” said Wilson, referring to the transition from the Devonian to the Carboniferous periods.
Wilson said paleontologists have wondered how ray-finned fish recovered from the extinction period as other groups of fish, such as the heavily armed category referred to as placoderms, were disappearing.
“The beach where this fossil was discovered tells us … this is a group of animals that is doing well, pretty quickly, after a mass extinction,” he said.
The paper theorizes that the feeding methods of the evolving teeth may have played a role, creating an evolutionary advantage for the species.
Wilson noted “that particular feature of the curved and pointy fang at the front and processing fangs at the back became a feature of many species in times to come.”
The area where the fossil was found — at Blue Beach on the Minas Basin, about 90 kilometres north of Halifax — was believed to be part of a vast freshwater lake not far from the ocean.
The research team’s paper credits Sonja Wood, former director of the Blue Beach Fossil Museum, for finding the fossilized jaw by urging Mansky to check along a creek that flowed onto the beach.
Wood, who died last year, was in a wheelchair and had urged her colleague to search the area.
“She had a good feeling about what could be found … and she said he should go and have a look,” said Wilson.
“He went down and sure enough it [the jaw fossil] was sitting right there,” he said, adding that Mansky managed to recover the fossil before a storm rolled through that night.
Wilson said more discoveries are possible as examination of the fossils from the Blue Beach area continues.
“We have lots of different anatomies that simply haven’t been described yet. And we’ll be working on that in a paper that’s coming up in a few months,” he said.
