'', a winged "grylloblattidan" from the mid-Cretaceous|left The earliest
stem-group representatives of Notoptera/Xenonomia had emerged by the
Late Carboniferous, around 320 million years ago. Early members of the group, which unlike modern notopterans had wings, have been referred to as members of "Grylloblattida" and "Reculida", with their relationships to modern notopterans historically being the subject of controversy. Winged "grylloblattidans" reached their apex of diversity during the
Permian (299-252 million years ago), where they represented up to a third of all insects at some localities. No fossil record of modern grylloblattids is known, though the winged
Aristovia and
Zygogrylloblatta are known from the
Burmese amber of Myanmar dating to the mid-
Cretaceous around 100 million years ago, have mouthparts very similar to modern grylloblattids, indicating their closer relationship to modern grylloblattids than to mantophasmatids. Mantophasmatids and grylloblattids are thought to have lost their wings independently. Winged "grylloblattidans" declined in diversity and abundance from the Triassic onwards, with the youngest records of winged "grylloblattidans" dating to the Early-mid Cretaceous. == List of extinct families ==