Dinosaurs might not have dental records, but their fossilized teeth offer fascinating clues into their dietary habits. Inspecting chemical signatures stored in the enamel, scientists writing in Palaeography, Palaeoclimatology, Palaeoecology found that different species of herbivores had different preferences and were partial to different parts of the plant — a fact that enabled vast and diverse ecosystems to flourish for millions of years.
“It’s really just more proof that this ecosystem was as spectacular as we thought it was,” lead author Liam Norris, a recent doctoral graduate at the University of Texas’ Jackson School of Geosciences, said in a press release.
Tooth Enamel of Dinosaurs
The dinosaurs subjected to this particular dental inspection were found in the Early Tithonian Carnegie Quarry at Dinosaur National Monument, an emporium of fossils on the border of Utah and Colorado. The site offers an intriguing snapshot of life in the Jurassic Period, some 150 million years ago, revealing high levels of diversity and a complex ecosystem with multiple large animals living alongside each other.
The researchers performed calcium isotope analysis on tooth enamel from three herbivorous dinosaurs, one carnivorous dinosaur, and a crocodyliform (Eutretauranosuchus). This included two Diplodocus (a long-necked plant-eater), two Camptosaurus (a short-armed, beaked herbivore), four Camarasaurus (a slightly smaller, stockier long-necked plant-eater), and five Allosaurus (a large meat-eater).
One benefit of using tooth enamel is that it is incredibly hardy. Its higher density and lower porosity mean it is more likely to remain stable over time compared to other materials, such as bone or dentine. Another reason teeth are such a valuable tool for paleontologists is their calcium content, which retains chemical signatures from the foods that were eaten.
By interpreting these signatures, the team was not only able to determine what plants dinosaurs ate, but also which parts of those plants, such as the bark or the leaves, were consumed.
Read More: The T. Rex Dined on Huge, Plant-Eating Dinosaurs — and Each Other
Dinosaur Dining Preferences
The results reveal how so many herbivores were able to coexist. Not only did they survive by eating different levels of the canopy — with taller dinosaurs munching on leaves closer to the top — but also by eating different parts of the plant in the first place.
The researchers found that Camptosaurus preferred the softer parts of plants, such as leaves and buds, whereas Camarasaurus displayed a penchant for woody plant tissues, regularly munching on conifers. The Diplodocus appeared to be less fussy, consuming soft ferns and horsetail plants as well as tougher parts of the plant. This may have been made possible by long necks that enabled them to reach plants high in the canopy as well as those closer to the ground.
“This differentiation in diet makes sense with what we see from the morphology of these animals: the different height, the different snout shape,” said Norris. “Then, we bring in this geochemical data, which is a very concrete piece of evidence to add to that pot.”
The team also found differences in the diets of the two meat-eating species: the Allosaurus and Eutretauranosuchus. While the results suggest the latter dined on a diet of fish, the former was probably an opportunistic carnivore, gorging on the flesh of plant-eating dinosaurs. The researchers note that bone did not appear to form a significant part of the Allosaurus’ diet, leading them to speculate that it specialized in ripping flesh.
Taken as a whole, the findings paint a picture of a colorful ecosystem containing a vast range of species with complementary dietary preferences. This, the researchers say, allowed them to co-exist for millions of years.
Read More: Fossils in 100-Million-Year-Old Sauropod Suggest They Didn’t Chew Their Food
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Palaeography, Palaeoclimatology, Palaeoecology. Calcium isotopes reveal niche partitioning within the dinosaur fauna of the Carnegie Quarry, Morrison Formation
Rosie McCall is a freelance writer living in London. She has covered science and health topics for publications, including IFLScience, Newsweek, and Health.
