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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: The Rise of Jaws
6 July 2011 1:00 pm
A new analysis of the first fish with the ability to bite is giving paleontologists plenty to chew on. Gnathostomes—vertebrates with jaws, including shark predecessors, the forebears of bony fish (including our own ancestors), and now-extinct lineages such as the armor-plated placoderms—originated between 444 million and 416 million years ago. As reported today in Nature, however, their rise to dominance was more complicated than previously thought. Paleontologists had hypothesized that the evolution of different jaw types, from slicers to crushers, allowed the gnathostomes to rapidly replace jawless fish. But, according to the new study, jawless fish coexisted with gnathostomes for millions of years. It was only after 400 million years ago, when all the major jaw types had been established, that gnathostomes began to take over. Biting may have given the gnathostomes an evolutionary edge, but, like their blood-sucking relative the lamprey, jawless fish hung on for a long time.
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