Researchers uncover world's oldest fossil impression of a flying insect

300 million-year-old discovery in an unlikely setting -- a suburban strip mall

MEDFORD/SOMERVILLE, Mass. - While paleontologists may scour remote, exotic places in search of prehistoric specimens, Tufts researchers have found what they believe to be the world's oldest whole-body fossil impression of a flying insect in a wooded field behind a strip mall in North Attleboro, Mass.

During a recent exploration as part of his senior project, Richard J. Knecht, a Tufts geology major, and Jake Benner, a paleontologist and senior lecturer in the Geology Department, set out to hunt for fossils at a location they learned of while reading a master's thesis that had been written in 1929. With chisels and hammers, the team reached the shale and sandstone outcropping described in the paper. There they delicately picked away pieces of rock before reaching a section that yielded fossils. Just below the surface, they uncovered a fossilized impression of a flying insect.

Not just any fossil

It was not just any fossil. Knecht says it is the world's oldest known full-body impression of a primitive flying insect, a 300 million-year-old specimen from the Carboniferous Period. It is a rare find in the specialized world of ichnology, which is the study of fossilized animal tracks, impressions and trails to investigate behavior. Knecht says a preserved full-body impression of a flying insect from this or any previous period has never been discovered.

The fossil, Benner says, "captures a moment in time over 300 million years ago when a flying insect just happened to land on a damp, muddy surface leaving almost a perfect impression of its body behind."

Knecht and Benner presented the fossil at the Second International Congress on Ichnology, in Krakow, Poland last month. The pair will present other trace fossils from the site, including tracks of amphibians and precursors to reptiles, at the Annual Meeting of the Geological Society of America meeting in Houston later this month.

Paleontologists use fossilized remains of insect bodies to study anatomy and develop hypotheses about evolutionary processes. Typically the only evidence available for this type of work is remains of insect wings. Bodies of primitive flying insects are rarely preserved and therefore little is known about them. The North Attleboro fossil will provide researchers with evidence of how it moved once it landed on a surface, as well as its stance, position of its legs and details about its abdomen and thorax.

The impression is about three inches long and is imprinted on the flat side of a rock. The impression does not contain direct evidence of the insect having wings but Knecht and Benner say evidence suggests that it was a winged insect. According to Benner, the insect's anatomy and body plan are consistent with those of primitive flying insects. He also points out that "there are no walking tracks leading up to the body impression, indicating that it came from above."