the oldest known insect fossil is the devonian "rhyniognatha", from the 411 million year old rhynie chert. it may have superficially resembled a modern-day silverfish insect. this species already possessed mandibles of a type associated with winged insects, suggesting that wings may already have evolved at this time. thus, anatomical records suggest the first insects may have appeared earlier, in the silurian period. genomic analysis puts their origin even further back in the ordovician period.