‘Dangerous predator’ — 350 million years old — is new species in Canada creekbed
On an inner beach in Nova Scotia, layers of stone and sediment are battered by water.
The area is susceptible to the extreme tides in the Bay of Fundy, pulling anything on the surface out to sea, possibly lost forever.
For centuries, researchers, geologists and paleontologists have studied Blue Beach because of its abundant fossil record, and in recent years they have worked to start collecting, preserving and categorizing the bones found there.
Researchers Chris Mansky and Sonja Wood founded the Blue Beach Fossil Museum as part of this mission, and now their work has led to the discovery of a new prehistoric species.
Wood, who died last year, is credited with finding a jaw bone for a previously undescribed species in a study published June 18 in the peer-reviewed Journal of Vertebrate Paleontology.
“She (a wheelchair user) was out with Chris along the road at Blue Beach when she got a good feeling that a fossil would be found in the nearby creek,” Conrad Wilson, a Ph.D. candidate at Carleton University and lead author on the study, told McClatchy News in an email. “She pointed Chris down the rocky embankment into the creek bed and that’s where he found the fossil.”
The jaw is long and curved and teeth protrude from the bone, according to the study. The teeth near the back of the jaw were conical and nearly vertical, while those near the front were strongly curved backward in a hook-like structure
The jaw was identified as a species of actinopterygian, or predatory ray-finned fish, a group that is “hugely important today,” Wilson said.
“Today, they include more than 50% of all vertebrates and pretty much any fish that is fished commercially, and range from sturgeon to tuna,” Wilson said. “... This one was close to 3 feet long and is strikingly different from its contemporaries because of the curvature of its jaws and the size and anatomy of its fangs.”
Each type of tooth served a different purpose in making the fish a “dangerous predator,” Wilson said.
Hooked teeth at the front of the jaw would capture the fish’s prey in their mouth, holding them in while the pointed fangs in the back could “pierce” the creature and “chop it up,” according to Wilson.
This is the earliest record of this kind of dentition in ray-finned fishes, appearing about 350 million years ago, Wilson said.
The species was named Sphyragnathus tyche, combining Greek words “sphyra,” meaning hammer and “gnathus,” meaning jaw for the genus, according to the study. The species name, Tyche, refers to the Greek goddess of fortune for “the fortunate circumstances of the fossil’s discovery.”
Aside from a distinction as a new species, the hammer jaw fish also tells researchers about how all ray-finned fish fared after a catastrophic event.
Lots of species were lost at the end of the Devonian period, which ended about 358.9 million years ago, to a mass extinction and the diversity of fish declined, Wilson wrote in a June 24 article published in The Conversation.
“One point of debate revolves around how actinopterygians (ray-finned fishes) diversified as the modern vertebrate world was born — whether they explored new ways of feeding or swimming first,” Wilson wrote.
By noting and analyzing the unique teeth, researchers suggest the group of fish focused first on changing their feeding strategy evolutionarily, instead of adapting their swimming, according to Wilson.
“The fossils are telling us about what the fish existing right after a mass extinction looked like,” Wilson told CBC News. “... 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.”
Blue Beach is on the inner shore of Nova Scotia, on Canada’s east coast.
The research team includes Wilson, Mansky and Jason S. Anderson.