In the Early Devonian Dundee Formation of Scotland, fossils of "P. anglicus" occur together with a wide array of different eurypterids, including "Erieopterus", "Pagea", "Tarsopterella" and "Stylonurus", as well as acanthodian fish "Ischnacanthus" and "Mesacanthus", shark "Climatius" and osteostracian fish "Cephalaspis". Fossils of "P. carmani" of similar age found in the Holland Quarry Shale Formation of Ohio also preserve a diverse Devonian fauna of various eurypterids, such as "Dolichopterus", "Strobilopterus" and "Erettopterus", as well as pteraspidomorph fish "Allocrytaspis" and placoderm fish "Aethapsis". Puncture wounds on fossil poraspid fish attributed to the related pterygotid "Jaekelopterus" demonstrate that pterygotids would have been capable of preying on armored fish such as pteraspidomorphs and placoderms. The deposits that yielded the fossils of "P. siemiradzkii" have also yielded fossils of "Eurypterus" and several genera of pteraspidomorph fish; "Larnovaspis", "Phialaspis", "Corvaspis" and "Podolaspis".