Megalograptus

General Background
Megalograptus was an erypterid that lived in North America during the Ordovician Peroid.It has 5 species known to science.When its spine covered arms were found,they were miss identified as graptolites.It was among the earliest genus of the erypterids.The maximum size was 4 feet long,it hunted early fish like Astraspis,trilobites and cephalopods.Their main predators were Larger erypterids like Pterygotus and the giant cephalopod Cameroceras(although juveniles were a prey item for the Megalograptus).