Dunkelosteus is an arthrodire placoderm that lived from 382 (Frasnian) to 358 (Famennian) years ago. 3 species, D. terreli, D. marsaisi, and D. magnificus are among the largest placoderm species to ever live. Dunkleosteus terelli, the species likely depicted in this show, is 6 meters long and about 1 tonne in weight; much less than the incorrect weight said in the show.
Hell on earthEdit
Dunkelosteus is depicted as hypercarnivores, feeding on fish, sharks, and cephalopods. When the plume erupts, the animals (and possibly some Dunkleosteus) close to it try to escape, with many dying in the process. As hundreds of years pass, Dunkleosteus begins to go into decline, forced to cannibalize eachother to stay alive. Eventually they would go extinct, killed off by hunger.
The show said Dunkelosteus weighed 20000 tons, which is far heavier than most animals that it likely shared its ecosystem with.