Scientists have identified plant fossils within the abdomen of the fossil of a dinosaur known as a sauropod, which lived about 94 to 101 million years ago. The findings provide evidence that these creatures were herbivores, and have suggested that gut microbes were vital for their digestion. The work has been reported in Current Biology.
“No genuine sauropod gut contents had ever been found anywhere before, despite sauropods being known from fossils found on every continent and despite the group being known to span at least 130 million years of time,” said first study author Stephen Poropat of Curtin University. “This finding confirms several hypotheses about the sauropod diet that had been made based on studies of their anatomy and comparisons with modern-day animals.”
If we want to understand how dinosaurs fit into ancient ecosystems and what types of roles they may have had, we have to understand their diets, the researchers noted. But that's no easy task, since dinosaurs fossils don't usually contain preserved gut contents, or cololites.
This is particularly true of sauropods. They were massive animals, and likely had a gigantic influence on terrestrial environments around the globe during the Jurassic and Cretaceous period. But since few gut contents have been found, information about sauropods' diet is largely inferred from characteristics like neck length, tooth wear, and jaw morphology.
When researchers and volunteers were analyzing a nearly complete young sauropod skeleton at the Australian Age of Dinosaurs Museum of Natural History, they found what appeared to be cololite. It was made up of plant fossils.
Further analysis indicated that sauropods don't seem to have chewed their food much. Instead, they consumed foliage and plants whole, including flowers, seeds, and leaves from various types of trees and plants. This suggests that Diamantinasaurus was an undiscerning, bulk feeder.
This young sauropod, a Diamantinasaurus, seems to have eaten both low- and high-growing plants. It also seems to have aimed for things that were easier to digest, like small shoots and seed pods. (But still, it wasn't concerned with chewing it.) As they grew bigger and older, the animals would be also able to access more food that grew higher off the ground.
Of course, this find only represents one case, and even then, it was the animal's last meal (or few). So there is still much we don't know, such as whether this is the diet of a stressed animal, or its regular food. Seasonality may also be a factor. And since the fossil is from a young animal, it may represent exactly like what adult sauropods ate, the researchers noted.
Sources: Cell Press, Current Biology
