Monday, November 21, 2005

Earlier/Mesozoic Grass?

ossilized dinosaur droppings found in central India show that giant dinosaurs known as titanosaurs ate grass, an international team of researchers reported on Thursday.

Few scientists had ever thought that dinosaurs grazed, because there was no evidence that grasses existed that long ago. They believed that the grinding teeth found in some dinosaur fossils were used for munching other plant matter, perhaps trees, like modern beavers chew on today.

So when Caroline Stromberg of the Swedish Museum of Natural History received photographs of fossilized dinosaur droppings from Vandana Prasad of the Birbal Sahni Institute of Palaeobotany in Lucknow, India, she hardly expected to see pieces of grass in them.

"I was very surprised to see them and even more surprised

to see that there was quite a diversity," Stromberg said in a telephone interview. "It was shocking but very exciting."

Prasad's team had been analyzing 65-million-year-old coprolites -- fossilized droppings -- that they believe were left by giant plant-eating sauropod dinosaurs.

They found the expected plant matter -- cycads and conifers and other plants known to have grown during the Cretaceous period.

They sent some photographs and then samples to Stromberg, who spotted tiny silica structures called phytoliths.

"It's indisputable that these are from grasses. The shape of these phytoliths indicate that they are from grasses," said Dolores Piperno, a paleobotanist at Washington's Smithsonian Institution who reviewed the study, published in the journal Science.


Read the rest here.

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