Mystery of the fang feeding fossilComment on this story
Johannesburg - A broken tooth left at a quarter-of-a-billion-year-old kill site has helped to establish a cause of death and reveal a feeding strategy that is used today.
The 35mm-long canine was found embedded in the fossilised skeleton of a mammal-like reptile, known as a dicynodont, that once roamed what is now the Karoo.
Scientists aren’t 100 percent sure who the fang once belonged too, but they don’t believe it was the predator that killed the large dicynodont. However, what this tooth has done is allow science a glimpse of feeding behaviour 250 million years ago.
“What we had here is a kind of cold case file, a forensic story,” said Nick Fordyce, a student at the University of Cape Town who worked on the project.
The dicynodont skeleton that Fordyce and colleagues Professor Anusuya Chinsamy-Turan and Dr Roger Smith worked on is on display in the Iziko Museum in Cape Town.
The skeleton even has a nickname: she is known as “Mamafura” or “old woman”.
Dicynodonts were common herbivores 250 million years ago, and this one was found near the town of Loxton in the Northern Cape in 1984. It was only later, when the specimen was being prepared, that the canine was noticed close to the femur.
“The specimen was found belly up, which is an indication of drowning. The body was initially deposited in mud,” said Fordyce, whose research appears in the latest issue of the South Africa Journal of Science.
It is suspected that some animals foraged alongside major rivers, which made them susceptible to flash floods.
What the researchers suspect is that the carnivore, which was the size of a border collie, scavenged off the dead animal after the waters had receded.
“This dicynodont was very big, so it was very unlikely that this predator killed it,” Fordyce explained. “We did consider that the carnivores might have hunted in a pack, but there is a lack of evidence for this.”
Evidence of a pack attack would have included a lot of bone damage and signs of trauma, said Fordyce. “The only bone damage had more to do with the tearing of flesh,” he said.
The position of the tooth suggests the scavenger began feeding from the rear, tucking into the soft underbelly just below the ribs. Bone damage even points to the carnivore having removed part of the hind limb bones so as to get better access to the softer flesh. “What we are seeing here is behaviour observed with modern-day predators like wild dogs. It is a nice example of how modern systems work and how they evolved,” Fordyce said.
As for what that mystery prehistoric predator was, the team do have a suspect in mind. Scanning electron microscope analysis of a cast of the tooth and its size make it a close match to aelurognathus, which came armed with sabre-like incisors.
The aelurognathus possibly passed on its dining habits to a host of predators that roam the savanna today. - The Star