Wikipedia
Dinichthyloidea
The Dinichthyloidea is an extinct superfamily of placoderms, armored fish most diverse during the Devonian. They contain numerous extremely large species, such as Titanichthys, presumed to be a planktivore, the apex predator Dinichthys, as well as numerous other genera of diverse size and habits, such as the tiny Rhachiosteus, the superficially tuna-like Bungartius, and the selenosteids and trematosteids.