The teeth of this species, called ‘Adelospondyli’, are unlike that of any other known living or extinct amphibian. They are the oldest animals known to have evolved sabers that would not have been used to chew, rip or grasp, but instead for display, the research concludes.
The findings indicate that the evolution of ‘sabre teeth’ is not restricted to mammals, but occurred independently in distantly related groups of vertebrates.
Saber-like teeth are rare among amphibians, and previously were only known to occur in the living species Solenodontid shrews and extinct groups of mammals called Metatherians. The research reveals that the evolution of ‘sabre teeth’ occurred at least twice in distantly related groups of vertebrates.
The fossils were discovered in 2010 in the Abo red beds of New Mexico, and have been meticulously studied and identified at the University of Edinburgh’s Grant Institute of Earth Science, working with colleagues in Zurich and the University of Pennsylvania.
The research, published in Nature Ecology & Evolution, was led and conceived by Dr Stephanie Pierce of the University of Vienna.
“The most striking feature of these animals was their prominent caniniform tooth, an adaptation we only thought happened much later in our evolutionary history,” she said.
“To have a structure so iconic of some mammalian predators turning up in an ancient amphibian challenges conventional wisdom about their function and evolution.”
Co-author, Professor Jenny Clack of the University of Cambridge said: “This discovery changes our understanding of the evolutionary history of vertebrates: this group now joins the list of animals that produced sabre teeth.”
The animals were between 50 to 75 cm long, had four well-developed limbs and a long tail, and would likely have spent much of their time in the water. They would have been at the top of food chain, hunting small fish and insects, and would have avoided larger predators by diving into water.
