Today was a busy day for me. I made an attempt to get to more posters this morning, but spent most of my time at just one poster, talking to Laura Vietti about her work with John Greer and John Soderberg on using optical techniques to quantify abrasion on the bones of marine animals. Laura and I have been talking about the issues of bone preservation at Carmel Church for some time, and this technique may eventually prove to be applicable there.
I did manage to get to a few other posters in the afternoon. Serina Brady and Warren Allmon compared endocranial casts of the Oligocene camelid Poebrotherium (example at the top of the page from AMNH) to modern llamas, to determine what brain structures have a high preservation potential. Rachel Racicot and others reported the collection of a rare Pliocene toothed whale from Iceland. Carol Mankiewicz showed pictures of a strange, unidentified trace fossil from the Cambrian sediments near Baraboo that branches below the surface (I thought it might be some type of holdfast structure).
Most of my afternoon was spent in one of the paleontology sessions. The third talk was Mark McMeniman’s provocatively titled “Triassic Kraken” talk, which had already received some notoriety on Twitter after a press release yesterday. The title caught my eye before the meeting, with the claim that the rich Nevada bonebed of the giant ichthyosaur Shonisaurus (below) was in fact a midden of a giant cephalopod .
Now, I’m on record supporting speculation in paleontology. But you have to have some data to back up your speculation, it has to be something that could reasonably happen in the real world, you have to be able to credibly rule out more mundane alternatives, and you have to be clear about where the data stops and the speculation begins. This talk met none of those criteria. After reading the abstract I found myself hoping that there was more to it than what was described, but in fact there was less. The sum total of the data was that a few (eight, I think, out of the entire bonebed) ichthyosaur vertebrae were arranged in a staggered pattern that vaguely resembled the sucker pattern in one modern squid taxon (although I thought it wasn’t very close match), and that a lot of the bones were broken and supposedly there was no other good explanation for how that could happen. There was no discussion about whether or not currents could be responsible for the vertebral arrangement, except a blanket statement that they couldn’t, with no supporting data. The breakage looked like the breakage in pretty much every whale skeleton I’ve ever collected, like these from Carmel Church:
The talk then went into some mostly incorrect or unsubstantiated speculation about how intelligent this mythical cephalopod (which would have been well over 30 meters in length) would have been. It was unfortunate that this talk somehow received press coverage, at least at some online sites. Even worse, so many people packed into the hall to see this talk that it was actually somewhat disruptive to the rather excellent talk that preceded it.
That talk, by Madeline Marshall and Raymond Rogers, made the case that large vertical burrows in a Cretaceous fluvial deposit in Madagascar were made by lungfish. In another trace fossil talk, Lidya Tarhan and Mary Droser looked at Cambrian burrows like the ones below from South Dakota and suggested that increased bioturbation later in the Phanerozoic may have resulted in poorer burrow preservation.
Adiël Klompmaker and René Fraaije reported on three tiny Jurassic lobsters that were apparently hiding inside an ammonite shell. Then it was back to trace fossils, as Patrick Getty, Andrew Bush, and Aaron Judge reexamined a Triassic dinosaur trackway site from the Hartford basin (similar to those at Dinosaur State Park, below). They suggest that most taxa were simply following the shoreline, but that the small theropods may have been going down to the water.
The session ended with paleobotany. A talk by Claire Belcher and others looked at the effects of varying oxygen levels on fire propagation. Their data suggest that below about 15% fires will fizzle out, and that above around 22% the fire will burn all available fuel. Late in the day were two talks on plants from the Cretaceous Cloverly Formation:
Nathan Jud reported a pre-angiosperm site near Ten Sleep, Wyoming, that is dominated by cycads. Brooke Haiar and Rick Lupia reported several Cloverly plant sites, including the Crooked Creek locality (below), and their data suggest that angiosperms moved into and became common in Wyoming during the course of deposition of the Cloverly.
After the talks it was time for the evening social events. Carleton College had an alumni gathering, and I got to see some of my old professors and classmates, in some cases for the first time in 20 years. In addition to Mary Savina (my sedimentology professor) and Tim Vick (who taught me how to plan field trips) I was happy to see my undergraduate advisor, Ed Buchwald; the photo below is Ed and me on a field trip back in 1991, when I was still a student at Carleton:
After the alumni reception, I joined a gathering of around a dozen geobloggers. Many of us only knew one another through our online personas, and it was interesting to hear us end up introducing ourselves by our blog titles or Twitter names; a sign of the times, I suppose. A good time was had by all, and I feel justified in blaming my fellow bloggers for my late post this evening as I was later than usual in returning to my hotel room to write!