300-Million-Year-Old Fossil Hints At Herbivore Evolution
Researchers have discovered an ancient lizard-like animal fossil that could lead to the bottom of the mystery of how small carnivores evolved into land based herbivores. The ancient animal is believed to be existing 300 million years ago.
"The evolution of herbivory was revolutionary to life on land because it meant terrestrial vertebrates could directly access the vast resources provided by terrestrial plants," said Robert Reisz, a professor from the University of Toronto's Department of Biology in a press release. "These herbivores in turn became a major food resource for large land predators."
The discovered fossil has been named 'E.martini'. Scientists believe that the animal was a carnivore and belonged to an ancient group of vertebrates called Synapsid. Modern mammals also belong to one branch of the Synapsida and the group has involved both into large predators and early terrestrial herbivores.
"Eocasea is one of the oldest relatives of modern mammals and closes a gap of about 20 million years to the next youngest members of the caseid family," said Jörg Fröbisch from the Museum für Naturkunde and Humboldt-University in Berlin. "This shows that caseid synapsids were much more ancient than previously documented in the fossil record." Fröbisch is also a co-author of the study.
E.martini existed on Earth around 80 million years before dinosaurs. The ancient animal was relatively small weighing just around 4.4 lbs.
"Eocasea is the first animal to start the process that has resulted in a terrestrial ecosystem with many plant eaters supporting fewer and fewer top predators," Reisz said. "When the ability to feed on plants occurred after Eocasea, it seems as though a threshold was passed."
"Multiple groups kept re-evolving the same herbivorous traits," Reisz added.
The study has been published online in the journal PLOS ONE.