CT Scan of Fossils Sheds Light on Tooth Replacement for Plant-Eating Dinosaurs

New fossils excavated by the Museums of Western Colorado from the Mygatt-Moore Quarry in Rabbit Valley reveal how different species of gigantic plant-eating dinosaurs were able to coexist in the same ecosystem with limited vegetation. In a newly published research article titled “Evidence for niche partitioning among ground-height browsing sauropods from the Upper Jurassic Morrison Formation of North America,” Museums of Western Colorado Curator of Paleontology, Dr. Julia McHugh, shows that this type of resource partitioning existed in the Late Jurassic Period of western Colorado.

Through a partnership with the Colorado Canyons Hospital in Fruita, Dr. McHugh was able to conduct CT scans of 152 million-year-old fossils and discovered that the dinosaur Apatosaurus had a higher number of replacement teeth than the large herbivorous dinosaur Diplodocus. These two kinds of dinosaurs looked very similar and lived together in the same places. However, these fossils show that Apatosaurus was adapted to replace more teeth than Diplodocus. This suggests that they may have eaten different plants, with Apatosaurus feeding on tougher vegetation than Diplodocus.

“Today, large herds of herbivores often eat different plants in their ecosystems in order to survive with limited resources,” says Dr. McHugh. “We know that competition exists in nature, and that animals have to divide resources to survive. However, finding evidence of this in the fossil record gets tricky, because behavior and actions rarely become fossils. That is why these new fossils are so important.”

This study was conducted in close partnership with the Colorado Canyons Hospital in Fruita. Thanks to Dr. Michael Neste M.D., Dr. McHugh was able use the hospital CT scanner to look inside these fossil “patients” and see replacement teeth hidden deep inside the bones. These scans allowed Dr. McHugh to assess the number and nature of how tooth replacement in these extinct animals happened. This partnership was integral to the success of the study.

The paleontological collection, research, and exhibition is hosted at Dinosaur Journey, which is part of the Museums of Western Colorado.

To learn more about Dr. McHugh’s findings, visit www.utahgeology.org/publication/giw-2018-v05-pp093-103-mchugh/.