Dunkleosteus

Dunkleosteus is an extinct genus of arthrodire placoderm fish that existed during the Late Devonian period, about 380–360 million years ago. Some of the species, such as D. terrelli, D. marsaisi, and D. magnificus, are among the largest arthrodire placoderms ever to have lived.

The largest species, D. terrelli, measuring up to 10 m (33 ft) and weighing 3.6 t (4.0 short tons), was a hypercarnivorous apex predator. Few other placoderms, save, perhaps, its contemporary Titanichthys, rivaled Dunkleosteus in size.

Dunkleosteus is a pachyosteomorph arthrodire originally placed in the family Dinichthyidae, a family composed mostly of large, carnivorous arthrodires like Gorgonichthys. Anderson (2009) suggests, because of its primitive jaw structure, Dunkleosteus should be placed outside the family Dinichthyidae, perhaps close to the base of the clade Pachyosteomorpha, near Eastmanosteus. Carr and Hlavin (2010) resurrect Dunkleosteidae and place Dunkleosteus, Eastmanosteus, and a few other genera from Dinichthyidae within it. (Dinichthyidae, in turn, is made into a monospecific family).