by Greg Mayer
I wasn’t able to make Chris Noto’s talk on Cretaceous coastal swamps last night, so I asked him to send me a summary of what he had to say and how the event went.
Turtle-Crunching Crocs and Cretaceous Wildfires at the Dinosaur Discovery Museum
by Chris Noto
First of all, I’d like to start by saying what a wonderful place the Dinosaur Discovery Museum is in Kenosha, Wisconsin. It is an important scientific and educational resource not only for the community, but the region as well. If you have not had a chance to visit the DDM yet, I highly recommend it. Best of all, it’s free to the public!
The evening provided a great turnout for the talk, about 20 or so in all, including university students (some were my students but, I should add, were not given credit for attending!), members of the community, teenagers, and younger children. Dr. Thomas Carr, a fellow paleontologist and director of the Carthage Institute of Paleontology (housed in the DDM), was also there.
The content of my talk surrounded work I have been doing with others at the Arlington Archosaur Site in Dallas, Texas. This site contains the remains of a diverse fossil assemblage, including the remains of turtles, crocodilians, dinosaurs, mammals, amphibians, lizards, sharks, bony fish, plants, and invertebrates. All of these lived approximately 96-97 million years ago in a coastal delta system on what was once a peninsula jutting westward into the Western Interior Seaway. One of the most interesting things about the AAS is that it preserves multiple sedimentary layers with charcoal and burned root fragments, evidence of intense, widespread wildfires that may have had an impact on the biodiversity of the ecosystem. The star of the show though is a new species of large crocodyliform. These monsters grew upwards of 7 meters (23 feet) long, with a 1 meter (3 foot) long head alone. Last year my colleagues Derek Main, Stephanie Drumheller, and I published a paper detailing the various tooth marks and feeding traces of the crocodyliform, which exhibited feeding behavior similar to that of living crocodiles and alligators. I described in detail how we built the case that the crocodyliform, and not a theropod dinosaur or other carnivore, made the tooth marks. I also showed the audience the process of how I am using laser scanning to produce 3D models of the fossils to reconstruct the skeleton of the new croc virtually, with the eventual aim of making a full 3D replica for display and research. I brought along with me some 3D printed models of bones and teeth to show. The talented digital artist Dave Killpack used my 3D model of the skull to create a fully-fleshed version of the croc’s head – with more reconstructions on the way. The potential applications of this technology are very exciting.
Afterwards I entertained a wide array of intelligent questions from the audience. I was particularly impressed by the questions the children asked me, including why the AAS croc had a big overhanging, bulbous snout and if any other crocs have one; how do we know that theropod dinosaurs weren’t rare, but we just haven’t found them yet; and one of my favorites, how do we know the oxygen content of the atmosphere in the past (I had shown a graph of atmospheric O2 over time). Many folks came up afterwards to look at the 3D-printed bones up close. All in all a good time sharing science with the public and I look forward to doing it again soon.