For more than 30 million years after dinosaurs first appeared, they remained inexplicably rare near the equator, where only a few small-bodied meat-eating dinosaurs made a living.
The long absence at low latitudes has been one of the great, unanswered questions about the rise of the dinosaurs.
Some 212 million years ago, landscapes weren’t all dinosaur-friendly: dry, hot, with wildfires.
Now the mystery has a solution, according to scientists who pieced together a detailed picture of the climate and ecology more than 200 million years ago at Ghost Ranch in northern New Mexico, a site rich with fossils.
The findings, reported today in the journal Proceedings of the National Academy of Sciences (PNAS), show that the tropical climate swung wildly with extremes of drought and intense heat.
Wildfires swept the landscape during arid regimes and reshaped the vegetation available for plant-eating animals.
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