LAWRENCE -- During the summer of 2002, University of Kansas entomologist Michael S. Engel and colleague David A. Grimaldi, a curator of New York City's American Museum of Natural History, were busy traveling to museums around the world researching various insect fossils for their new book.
Little did Engel and Grimaldi know that they would make a major rediscovery with a new twist on a visit to London's Natural History Museum. They confirmed 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.
"We were very surprised to find out Rhyniognatha was indeed an insect," said Engel, an assistant professor and curator of the division of entomology at KU's Natural History Museum and Biodiversity Research Center. "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."
The researchers estimate Rhyniognatha to be around 412 million years old. Prior to this discovery, the oldest known winged insects were thought to be around 325 million years old.
"The implication of this discovery is that flight is lot older than we thought," Engel said.
Their findings will be 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.
"Tillyard hedged his bets on whether Rhyniognatha was an insect," Engel said. "Once he finished studying the fossil, there really were no other scientists that wanted to take a look at it."
Using special microscopes, Engel and 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.
Prior to Engel's discovery, the oldest known insect, a wingless variety called Archaeognatha (pronounced ARK-ee-o-nay-thuh), was found in 1984 in Gilboa, N.Y., and probably dates back 379 million years. Another wingless insect fossil found in 1988 in Quebec, Canada, is estimated to be around 390 million years old. More study needs to be conducted on the Quebec insect to confirm its true age, according to Engel.
With the discovery of Rhyniognatha, there is now a gap of 87 million years between it and the next oldest flying insects, which already were remarkably diverse from 325 million years ago.
"There is still so much we need to learn," Engel said. "How did these insects refine flight between Rhyniognatha and the later insects? How did the environment play a factor in their flight?"
The next step for Engel is to find more grant money to keep researching areas of the world plentiful with insect fossils, as well as find new ones.
"Kansas has a wonderful site for insect fossils south of Abilene," Engel said. "There are other good sites in Russia, China, Greenland and the Falkland Islands."
Currently, 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.
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