The Heart of a Placoderm

Friends know I love the ancient armored predator Dunkleosteus, which sort of resembles a steampunk submarine with a guillotine on the front. The Dunk was one of 300 species of placoderms. Now we have an amazing find in Australia - a placoderm's heart, with enough fossilized material to study in detail. Soft tissues don't fossilize nearly as often or as well as bones or teeth, but when conditions are right, paleontologists can find enough to teach them a great deal. In this case, they sound a slightly flattened heart compared to one like ours, described as S-shaped. The heart has two chambers. The releases so far don't include the species. From the drawings in this article, it's not Dunk, and I can find illustrations of a dozen species it COULD be, but I'll update that as soon as we know.