Long thought to be fueled by increased atmospheric oxygen concentration, enormous griffinflies from the Carboniferous period, 300 million years ago, may have grown large for other reasons, according to new research led by University of Pretoria paleontologist Edward Snelling. Gigantic griffinfly in a Carboniferous forest. In the 1990s, scientists suggested a period of high atmospheric oxygen around 300 million years ago coincided with the occurrence...
