Explanation for why we don't see two-foot-long dragonflies anymore fails

A century-old explanation for the disappearance of two-foot-long dragonflies has collapsed, rewriting paleontology. Researchers found that prehistoric oxygen levels were only 20% higher than today's—far below the 35% threshold once thought necessary for giant insects. The data directly contradicts a 2012 hypothesis that linked insect gigantism to hyperoxic skies, proving the link was weaker than assumed. Without this explanation, the fossil record of these 300-million-year-old Meganeura remains an unsolved puzzle, challenging assumptions about ancient atmospheres.