About 250 million years ago, at the end of the Permian period, something killed some 90 percent of the planet's species. Less than 5 percent of the animal species in the seas survived. On land ...
Then 252 million years ago came the Permian-Triassic extinction event ... This is the lineage to which present-day crocodiles and alligators belong. They are a paltry bunch today, about 25 ...
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