As adults, Stegosaurus could reach 4 meters (13 ft) off the ground, 9 meters (30 ft) in length, and weigh up to 4.5 metric tons (5 short tons). As babies, they were about the size of kittens. Tracks discovered out in Colorado have been imaged in 3D, which will give researchers greater insight into their locomotion and will hopefully be used to identify more tracks.
The images of the tracks were taken in 2006 by Matthew Mossbrucker, director of Colorado’s Morrison Natural History Museum. They were converted into 3D images using a technique called photogrammetry, which has roots back to the 1850s. While it used to be a painstaking process of using triangulation to calculate distances and depths based on many photographs under a variety of lighting conditions, advances in computer technology has afforded the ability to easily make 3D representations of objects from images. This allows for a variety of precise measurements to be taken easily.
Though several photographs are still needed, 3D models can rendered in under 15 minutes. Photos of the tracks were taken from Mossbrucker’s iPhone and converted into 3D models by Heinrich Mallison from Museum für Naturkunde in Berlin.
"In recent years, the programs and the computers have improved so much that now we can calculate 10 million individual points in the time it used to take to calculate one," Mallison reported to Live Science.
In the case of dinosaur tracks, photogrammetry allows researchers to explore not only the size of the footprint, but also the distance between tracks and the depth. In addition to information about the dinosaur’s anatomy, this also gives researchers clues about how the dinosaurs moved. Tracks that are less pronounced might indicate that the dinosaur was running, and tracks that are deeper on one side could help explain the mechanics of how they walked and where most of the weight is placed.
Tracks of infant dinosaurs are fairly rare, so there is still a great amount of information to be obtained by modeling them in 3D. Mossbrucker identified baby sauropod tracks back in 2010, though tracks from the forelimbs were absent. This could indicate that as infants, these dinosaurs raced on two legs. In the future, photogrammetry could help resolve that issue.
Though paleontologists are focusing on making 3D tracks of rare tracks, like those by infant Stegosarus, future studies will hopefully expand to all dinosaur tracks in order to get a better understanding of dinosaur behavior.
The tracks are currently on display at the Morrison Natural History Museum.
[Hat tip: Stephanie Pappas, Live Science]