The age of fish
A pair of paleobiologists from Scripps Institution of Oceanography, University of California, San Diego, have determined that the world’s most numerous and diverse vertebrates--ray-finned fish--began their ecological dominance of the oceans 66 million years ago, aided by the mass extinction event that killed off dinosaurs. Researchers analyzed the microscopic teeth of fish found in sediment cores around the world and found that the abundance of ray-finned fish teeth began to explode in the aftermath of the mass die-off of species, which was triggered by an asteroid strike in the Yucatan Peninsula. Scientists refer to this episode as the Cretaceous-Paleogene extinction event.
Provided by the Scripps Institution of Oceanography