KU entomologist rediscovers world's oldest known insect, forgotten in a London museum

The oldest known winged insects were thought to be around 325 million years old. Thanks to a KU entomologist, think again.

In the summer of 2002, KU's Michael S. Engel and a colleague from the American Museum of Natural History visited London's Natural History Museum for research on a book. They ended up, quite unexpectedly, to confirm the existence of the world's oldest known insect, called Rhyniognatha hirsti [RYN-ee-oh-nay-thuh her-stee], originally found by another entomologist in 1928 and left virtually undisturbed on the museum's shelves since that time.

The researchers estimate Rhyniognatha to be around 412 million years old

"The implication of this discovery is that flight is a lot older than we thought," said Engel, an assistant professor and curator of the division of entomology at KU's Natural History Museum and Biodiversity Research Center.

"We were very surprised to find out Rhyniognatha was indeed an insect," said Engel. "Not only can we confirm that it's an insect, but Rhyniognatha was most likely a winged insect, predating other insects with wings by many millions of years."

Their findings were published Feb. 12 in the journal Nature.

Australian R.J. Tillyard is credited with originally discovering the insectlike fossil preserved in crystallized rock-called chert-76 years ago in Rhynie, Scotland. When Tillyard studied the fossil-naming it for the city in which he found it-he could not say for certain whether his discovery was indeed an insect or was really a hexapod, an organism related to insects. Adding to Tillyard's difficulty was that only the head of the insect was preserved, not the whole body.

Using special microscopes, Engel and his museum colleague David A. Grimaldi were able to focus on the mandibles-or jaws-of Rhyniognatha and discovered that the jaws had a similar structure to other winged insects. Other scientists confirmed their findings. The insect's jaws are about two-tenths of a millimeter in length. The head is around a millimeter in length, while Engel estimates the entire insect probably was between 6 and 7 millimeters in length.

Engel and Grimaldi are the only two professional entomologists studying insect fossils in North America. They will publish their book, "Evolution of the Insects" (Cambridge University Press), later this year.