January 29, 1998 -- A team of researchers from the American Museum of Natural History announced today in the journal Nature the discovery of the oldest fossil ants ever found. The extremely rare 92-million-year-old ants are preserved in amber from a location in New Jersey that has produced some of the world's most important amber-encased fossils. The new specimens are 50 million years older than the most ancient fossils that were clearly recognized as ants; the find thus proves unequivocally the existence of ants back into the Age of the Dinosaurs. The new specimens have important implications for understanding both the origin of ants and their rise to a position of ecological dominance in the world today.
The new ant specimens are of particular consequence because they show the presence of a "metapleural gland," which is the distinguishing anatomical feature of ants and is a key to their ability to live in colonies underground or in rotting trees. This gland, found above the hind legs, secretes a substance that functions as an antibiotic and prevents bacteria and fungi from invading the ants' nests and infecting the members of the colony. The development of this gland is believed to be associated with the evolution of the ants' social system, which has been a key factor in their tremendous ecological dominance. Ants are so successful that they represent up to 25% of the total animal biomass in Amazonia; even in New York City's Central Park they are, by weight, the most common creature.
The new specimens comprise three worker and four male ants. One of the
workers is a complete, well-preserved specimen from the group known as
Sphecomyrma freyi, a primitive kind of ant. This insect was first
described in 1967 by renowned entomologist E.O. Wilson and his colleagues,
but because no metapleural gland was clearly visible, it was uncertain at
that time whether it was truly an ant. The
Contact: Elizabeth Chapman
American Museum of Natural History