Leaving an ImpressionThe oldest known full-body impression of a flying insect has been discovered, a new study says.The 300-million-year-old fossil (seen in an undated picture), which dates to the Carboniferous period, was likely made by an ancestor of the mayfly, scientists say. (See picture: "Oldest-Ever Bee Found in Amber.")In 2008, fossil hunters found the ancient imprint while searching woods behind a suburban shopping mall in North Attleboro, Massachusetts. The extremely rare find "is like winning the lottery," study leader Richard J. Knecht, a geology student at Tufts University, told National Geographic News at the time.That's because the bodies of flying insects are usually not preserved due to their softer, fragile nature, he said. Scientists more often find only the remains of wings, which are not digested easily by predators.The 3-inch (7.6-centimeter) insect that made this imprint likely stayed in the mud long enough to move its legs before flying off, leaving a near-perfect impression, Knecht said in 2008.The oldest flying-insect study appeared this week in the journal Proceedings of the National Academy of Sciences.

Photograph by Jacob Benner, Tufts University