Abstract
The occurrence of placoderms in the Prague Basin (Bohemian Massif; Czech Republic) shows a very unsteady distribution in space and time. The most abundant specimens are in the Lochkovian and, through decrease in the Pragian, they become rare towards the Givetian.
The primitive acanthothoracids dominating in the Lochkovian and Pragian are completely replaced by arthrodires at the beginning of the Emsian. All placoderms in the Prague Basin, without any regard to their dimensions, had smooth jaws which is a proof of their non-predatory feeding habit.
Although placoderm diversity is generally considered to reflect the Devonian nekton revolution, the abundance of these vertebrates in the Prague Basin displays a decrease, i.e. an inverse tendency to the global one.