Analyses of fossilized dinosaur feces in India reveal the remains of at least five types of grasses. The finding not only provides the first evidence of grass-eating dinosaurs but also shows that grasses evolved diverse forms much earlier than scientists had previously recognized.
Bits of silica called phytoliths indicate the grasses' presence. The tiny crystals, which form within cells of many plants, are especially plentiful in grasses, according to Caroline A.E. Strömberg, a paleobotanist at the Swedish Museum of Natural History in Stockholm. Because each type of grass produces distinctly shaped phytoliths, scientists use the readily preserved grit to identify the mix that once grew in an area.