Palaeomylus (meaning 'ancient grinder') is an extinct Devonian ptychodontid placoderm fish.
There are seven species accepted in this genus:[1]
The generic name is derived from Greek (Palaeo, meaning "ancient") and (mylos, meaning "grinder").
Not to be confused with the junior homonym Palaeomylus, which is an early diverging member of the mammal group Glires.[2]
P. greenei, P. crassus, and the type species P. frangens were originally classified as a species of Rhynchodus, before being moved to a new genus, Palaeomylus, in 1891. The first was found in Wisconsin, while the latter two species were found in Ohio. P. predator was found near Gerolstein, Germany.[3]