The oldest known full-body impression of a flying insect was preserved in 300 million-year-old sandstone.
- The oldest full-body fossil of the impression of a flying insect has been found in Massachusetts.
- The fossil is 310-312 million years old and represents the progenitor of modern mayflies.
Some 312 million years ago, a mayfly landed at the muddy edge of a puddle and then flew away. The mud of the tropical floodplain happened to be the perfect consistency to retain a detailed impression of the mayfly's body -- including details of its body segments and marks made by its claws.
The next flood covered the impression with silt, preserving it as it hardened into rock over subsequent millennia.
The fossil was discovered in 2008 when Tufts University undergraduate Richard Knecht was lost in a swamp in some woods behind a Massachusetts strip mall, searching for a rock formation believed to harbor fossils, according to a 1929 graduate thesis.
As he emerged from the swamp he came to a rock outcrop of the type he was looking for. "I grabbed a loose piece on the outer edge of it and it was already naturally split as rocks tend to do as they weather,'" said Knecht, who now works at Harvard University's Museum of Comparative Zoology.