Editing Placoderm (section)

====Pseudopetalichthyida ====
[[File:Pseudopetalichthys problematica.jpg|thumb|upright|left|''[[Pseudopetalicthys problematica]]'']]
[[Pseudopetalichthyida]] ("false petalichthyids") is a group of elongated, possibly flattened fishes comprising three, poorly preserved and poorly studied genera. It is known only from rare fossils in Lower Devonian strata in [[Hunsrück]], Germany. Like ''[[Stensioella heintzi]]'', and the [[Rhenanida]], the pseudopetalichthids had armour made up of a mosaic of tubercles. Like ''[[Stensioella heintzi]]'', the pseudopetalichthids' placement within Placodermi is suspect. The matter is not easy to resolve because there are no complete, undamaged and articulated specimens. The anatomical studies done on the crushed specimens that have been found indicate that if they are placoderms, they may be a group more advanced than the [[ptyctodont]]s. As such, placoderm experts consider [[Pseudopetalichthyida]] to be the sister group of the [[Arthrodires]] + [[Phyllolepida]] + [[Antiarchi]] [[Speciation#Genetics|trichotomy]] and the [[Acanthothoraci]] + [[Rhenanida]] [[dichotomy]].