Rhyniognatha

The earliest evidence of insects comes from fragmentary remains preserved in chert from Rhynie, Scotland.  This same deposit yielded the famous hexapod, Rhyniella praecursor Hirst & Maulik, 1926 (Collembola), long-believed to be the only hexapod from the lowermost Devonian.  Recently, however, the remains of Rhyniognatha hirsti Tillyard, 1928 have been identified as insectan.  Making Rhyniognatha the oldest insect.

Not only was Rhyniognatha an insect, but it appears to have been a more derived insect than one might at first believe.  In fact, Rhyniognatha has traits known only among the Metapterygota, suggesting that this fossil may have been winged.  If this were the case, then the origin of wings must have been millions of years earlier than previously believed.  The first fossilized wings are from the very base of the Late Carboniferous, but already at that time a diversity of pterygotan forms is in existence.  The radiation of flying forms must have occurred much earlier.  Rhyniognatha suggests it may have occurred as long ago as the Early Devonian.

The more derived structure of Rhyniognatha also indicates that the origin and initial diversification of insects must have occurred even earlier, sometime in the Silurian.  Since the earliest evidence of animal terrestrialization comes from the Silurian it may be that insects were a component of the first terrestrial communities.

Rhyniognatha hirsti
Tillyard, 1928