Editing Placoderm (section)

====Petalichthyida====
[[File:Lunaspis.png|thumb|upright|''[[Lunaspis]]'']]
[[Petalichthyida]] ("thin-plated fish") were small, flattened placoderms, typified by their splayed fins and numerous tubercles that decorated all of the plates and scales of their armour. They reached a peak in diversity during the [[Early Devonian]] and were found throughout the world. The petalichthids ''[[Lunaspis]]'' and ''Wijdeaspis'' are among the best known. There was an independent diversification event that occurred in what is now Southern China, producing a handful of unique genera that were once placed in their own order, "Quasipetalichthyida", named after the first discovered species there, ''[[Quasipetalichthys haikouensis]]''. Soon after the petalichthids' diversification, they went into decline. Because they had compressed body forms, it is supposed they were bottom-dwellers that pursued or ambushed smaller fish. Their diet is not clear, as none of the fossil specimens found have preserved mouth parts.