Surprised scientists have discovered the remains of a saber-toothed vegetarian. The leaf-crunching animal _ about the size of a large dog _ lived 260 million years ago in what is now Brazil, researchers report in Friday's edition of the journal Science. Its upper canine teeth were nearly 5 inches long.
Such large teeth are more often the mark of a meat-eating animal, used to capture and kill prey.
The enormous canines were likely used by the plant-eating animals to fight each other or protect against predators, said research leader Juan Carlos Cisneros of the University of Piaui in northeastern Brazil.
For example, they might have fought for territory, resources or females, like the modern musk deer, which also have a pair of large, tusklike teeth, he said via email.
"These situations are extremely important for the survival of an individual and the success of a species," he said. Discovering animals like this "shows us how nature is extremely creative in providing solutions for several life tasks."
In addition to its saber shaped fangs, the newly discovered animal named Tiarajudens eccentricus (tee-AH-ruh-HOO-denz ek-SIN-trik-us) had rows of teeth on the roof of its mouth for chewing, the researchers said. The lower jaw was incomplete, but they expect it would have had similar rows of teeth.
Tiarajudens was part of a group of animals known as anomodonts, sometimes called "mammal-like reptiles" and a major plant eater of their time.
The discovery provides novel insights into early tooth differences in these ancient animals and the evolution of plant eating and its complex social interactions, commented Joerg Froebisch of Humboldt University in Berlin, who was not part of Cisneros' research team.
The evolution of saber teeth is exceedingly uncommon in plant-eating animals, said Froebisch, calling the canines in the Brazilian anomodont "extraordinary."
He said the animal seems to belong to a new, unusual group of anomodonts that lived on the ancient southern supercontinent now called Gondwana. Before drift formed the present continents, Gondwana included what is now Antarctica, South America, Africa, Madagascar and Australia.