A 260-million-year-old mammal-like reptile, the first that could chew and digest thick vegetation, spurred the evolution of modern-day land ecosystems, Canadian researchers reported in Thursday's Nature. Suminia getmanovi, a small creature similar to a monkey or rodent that preceded dinosaurs by about 50 million years, was a champion chewer.
Unlike other herbivores of its time, which simply tore off leaves and swallowed them whole, Suminia was able to chew and shred leaves with its huge teeth--allowing it to eat more, absorb more nutrients and process food more efficiently. Herbivores, or plant-eaters, first appeared on land 290 million years ago, but their numbers were limited. Scientists said Suminia's unique chewing ability was the beginning of more varied vertebrate life on land.