Wednesday, February 20, 2013

Shark-eating whales? Scientists identify four new whale species

Teeth of a fossilized whale called 'Willy' are severely worn down, suggesting that this previously unknown species of whale may have eaten large animals like sharks.

By Douglas Main,?Our Amazing Planet / February 19, 2013

These teeth, from one of the whale fossils found by Meredith Rivin and her fellow researchers, suggest the size of the extinct whales. Teeth are much harder than bone, so resist the ravages of geologic time better than bones do.

Cooper Archaeological and Paleontological Center / TechNewsMedia

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Fossils uncovered during construction of a roadway in Southern California have revealed four new species of ancient whales, according to research presented here at the annual meeting of the American Association for the Advancement of Science (AAAS) on Sunday (Feb. 17).

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One of the species, dubbed "Willy," is much larger than the others and may have eaten sharks, said Meredith Rivin, a paleontologist at the Cooper Archaeological and Paleontological Center in Fullerton, Calif., and part of the team that studied the fossils.

The fossils were excavated a decade ago, but are only now giving up their secrets, in part because it takes so long to separate the fossils from the rocks, Rivin said. "For the last 10 years? I've been trying to 'free Willy,'" Rivin said.

Whale teeth

These animals were toothed, baleen whales, and swam the oceans from about 17 million to 19 million years ago, Rivin said. That's quite a surprise, since this group was thought to have gone extinct about 5 million years earlier, she said.

Most of the world's largest whales belong to a suborder called Mysticeti, which all use a structure called baleen to filter food from the oceans. Their earliest ancestors, however, had teeth. Although these four species of whale don't appear to be direct relatives of modern baleen whales, they may represent transitional forms between the earlier toothed whales and toothless baleen whales, Rivin said. Modern baleen whales like fin whales have teeth only as embryos; the teeth are reabsorbed long before birth, she added.

All modern whales evolved from a single type of land mammal about 55 million years ago, Rivin said. These animals were quite small, about the size of a modern golden retriever, she noted. ?

Source: http://rss.csmonitor.com/~r/feeds/science/~3/fX071FXyAF4/Shark-eating-whales-Scientists-identify-four-new-whale-species

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