"A new study has found the first evidence of sophisticated breathing organs in 450-million-year-old sea creatures. Contrary to previous thought, trilobites were leg breathers, with structures resembling gills hanging off their thighs. 

Trilobites were a group of marine animals with half-moon-like heads that resembled horseshoe crabs, and they were wildly successful in terms of evolution. Though they are now extinct, they survived for more than 250 million years — longer than the dinosaurs. "

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