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12 December 2013 1:00 pm ,
Vol. 342 ,
The iconic 125-year-old Lick Observatory on Mount Hamilton near San Jose, California, is facing the threat of closure...
Recent results from the Curiosity Mars rover have helped scientists formulate a plan for the next phase of its mission...
A new, remarkably powerful drug that cripples the hepatitis C virus (HCV) came to market last week, but it sells for $...
In pretoothbrush populations, gumlines would often be marred by a thick, visible crust of calcium phosphate, food...
Evolutionary biologists have long studied how the Mexican tetra, a drab fish that lives in rivers and creeks but has...
Victorian astronomers spent countless hours laboriously charting the positions of stars in the sky. Such sky mapping,...
In an ambitious project to study 1000 years of sickness and health, researchers are excavating the graveyard of the now...
Stefan Behnisch has won awards for designing science labs and other buildings that are smart, sustainable, and...
- 12 December 2013 1:00 pm , Vol. 342 , #6164
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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.
See more ScienceShots.