OK, it's Shark Week, with the usual mix of good scientific shows (about three of them) and hyped shows with celebrities' pretending they are in danger (plus whatever those morons from Jackass think they're doing. I hope the shark that bit that granitebrain didn't become ill.) In the Devonian era, sharks were called "lunch." My favorite predator, Dunkleosteus terrelli, a cross between a steampunk submarine and a giant staple remover, reigned supreme.
Books written before the 21st century often quote lengths of 9-10 meters for Dunks. Today you're more likely to read 7 or 8 meters. That's still bigger than the biggest Great Whites.
Of course, everyone want to know what the top end of the size range is. The bone along the side of the lower jaw is called the infragnathal. This photo shows a complete right infragnathal (top) and the partial left infragnathal from the famous Cleveland Museum of Natural History specimen CMNH 5936. CMNH 5936 might have measured up to 8.9 meters in life, although people still argue about the tail. (These people are right, by the way.)
Matt Friedman provided this photo. Here's his paper on Palaeozoic jawed vertebrates. Is 5936 the biggest ever? It's probably very close, although I understand there a fragment of a supragnathal that might have surpassed it. Of course, we'll never be certain. Paleontologists have estimated two and a half billion T. rexes have lived and died. Humans have identified fewer than a hundred individuals, and there are only 32 mostly-incomplete skeletons. Who knows how many Dunks we've missed?
The Dunk doesn't have the media presence of the denizens of Shark Week. It appears briefly in a couple of documentaries and has been stuck in a few awful films. There's a new book out for school kids by Ben Garrod - I'll review that soon. Despite my years of fascination with the Dunk, I learned something new there. I thought the only fossils were of the head/armor and a bit of anterior spine, but there is in fact a pectoral fin fossil, too. I'm embarrassed, because I've talked to people at CMNH and looked at their publications, and I missed the saga of CMNH 8982.
No one is certain what the non-fossil portions of D. terrelli looked like, but the blanks are slowly being filled in. My photo of the specimen from the Denver Museum of Natural History, below, reminds us that, no matter what they looked like, they looked scary enough to deserve their own week. Or at least their own documentary.
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