Above: Type and only specimen of the pterygote insect Rhyniognatha hirsti (anterior towards the top) showing the sharp, bladed mandibles (m). The mandibles are directly comparable to those seen in the pterygote clade Metapterygota. Rhyniognatha is a relatively derived basal insect, and  may have possessed primitive wings (Engel & Grimaldi 2004)  (scale bar = 200µm) (Copyright owned by The Natural History Museum).