1. The metapleural gland secretes known antibiotics, which could be
of use to other species.
2. The ant fossils include advanced species that indicate considerable
evolution, allowing
some extrapolation backward from the 92 Myr age of the fossils to an
estimated origin
of ants 130 Myr back.
So, if Caudipteryx were so inclined, it could, possibly, get rid of
those nasty lice by
"anting".
-Gus Derkits
Quotes from the AMNH web site:
...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.
The discovery of both primitive and more advanced fossil ants in 92-million-year-old amber shows that the major lineages of ants arose before the great extinction at the end of the Cretaceous, 65 million years ago. A reasonable estimate would place the origin of ants in the Lower Cretaceous at about 130 million years ago.