Southbound

We'll be headed for the coast in the morning. Not sure how much you'll see of me for the next week or so. I expect I'll be checking in, especially if something interesting comes up. At the very least, I should be able to provide an update on the situation down there. But, I need some time off. Those of you that have been up close and personal the last few months know that.

I'll leave you with Bon Iver, and a tip o' the hat to Chris. Have a good break - see you soon.

Fish o' the Day - Dunkleosteus

Our first no-longer-with-us-FOD. Dunkleosteus terrelli was a placoderm, an armored group that were among the first groups of jawed fishes, and lived some 370 million years ago during the latter part of the Devonian period. His claim to fame is his size - Dunkleosteus could reach 30 feet in length and weigh upward of three tons. They're best known for their bony skulls and blade-like jaws - we don't really have a good idea what the rear of the fish might have looked like, and have extrapolated from similar species. Dunkleosteus had no teeth, but employed the beak-like plates on the jaw to slice and dice its prey. A detailed analysis of jaw structure reveals that they may have had one of the most powerful bites of any predator that ever lived. When Dunkleosteus opened its mouth, the upper jaw lifted and the lower jaw simultaneously dropped - unusual among jawed vertebrates. When the jaws slammed shut, they delivered a force of perhaps 8,000 pounds per square inch. Great white sharks and some of the alligators generate similar forces among living animals.

Dunkleosteus, clearly a top predator, apparently prowled inshore waters in search of food. It's unclear whether they also cruised the open ocean.

Now, for some completely inaudible commentary...

Fish trails

The Green River formation is famous for its fossil fish, which lived some 50 million years ago in what is now known as Fossil Lake. The site, now part of Fossil Butte National Monument in Wyoming, has yielded a rich and diverse group of Eocene fish, including Notegoneus osculus. That's him at left. Now, Emory paleontologist Tony Martin has interpreted trace fossils in the ancient lake bed to see into the past.

Martin's specialty is ichnology, that branch of geology/paleontology that deals with the traces left by organisms. While neoichnologists might interpret tracks or burrows to understand behavior of living organisms, paleoichnologists do them one better. They examine the fossilized evidence of past behavior and use it to add to our understanding of the biology of long-dead species.

Martin and his co-workers employed high-resolution digital images and mathematical analyses to determine that the traces left on the deep bottom of Fossil Lake were likely produced by an 18 inch N. osculus as is used the fins on the posterior part of its body to wriggle across the bottom and employ its subterminal mouth to feed on benthic organisms.

Martin actually visited Small Southern a couple of years ago. One of my colleagues has collaborated with him on many projects, and was able to persuade him to present a seminar for our students. As good a guy as he is a scientist.