The Phyllolepis concentrica, a species of Phyllolepis which lived in freshwater, was discovered by L. Agassiz in the 90's.
The species of Phyllolepis, themselves, are restricted to the Famennian-aged freshwater strata of the Late Devonian, around 360 million years ago. Phyllolepis concentrica L. Agassiz Phyllolepis lived in freshwater environments, possibly rivers and streams. 
