The new issue of Prehistoric Times (#120, Winter 2017) has a great article on the paleo-artistry of Zdenek Burian, including reproductions of two paintings containing Dunkleosteus terrelli (then Dinichthys) from 1955 and 1967.
I'm not reproducing them here for copyright reasons, but while he
worked assiduously with paleontologists to make his illustrations (which
appeared most famously in Dr. Josef Augusta's very influential
Prehistoric Animals (1956), where Burian got co-credit on the cover), his Dunk is a little odd to me. It's the most smooth and streamlined Dunk I've ever seen, tapering perfectly like a nuclear submarine to an elongated teardrop.
That muscle and skin made the armor almost invisible is certainly
possible, but the eel-like tail isn't very substantive, and I am certain
the pectoral fins are too small: they needed to precisely control a ton
of head/armor stretching several feet ahead of them. All that said, the
illustrations are wonderful, bringing to life the great predator, its
relatives, and its surroundings: I'm looking for a copy of Prehistoric
Animals right now.