The last meal of a huge armored dinosaur was found 110 million years later, still in its fossilized womb, in what is now northern Alberta.
Described for the first time in 2017, this thorny 1,300-kilogram (approximately 2,800-pound) nodosaur discovered in 2011 is believed to contain the best-preserved dinosaur stomach found to date.
After five years of painstaking work exposing the dinosaur inside the sea rock, the mass of the size of a soccer ball in the belly has now given us the first definitive glimpse of what the great vegetarian dinosaurs once ate. over all these millennia.
“When people see this magnificent fossil and we are told that we know what was their last meal because their stomach was so well kept inside the skeleton, it will almost bring the beast back to life for them, giving a glimpse of how the animal actually transported its daily activities, where it lived and what its favorite food was, “says geologist Jim Basinger of the University of Saskatchewan in Canada.
This is something we have never really known about a herbivorous dinosaur. Although this dinosaur represents only one species of a family of ankylosaurs – known as Borealopelta markmitchelli and without the archetypal tail of the “club” of its closest relatives – this could help us better understand the digestion and physiology of dinosaurs, especially since ankylosaurs are found on all continents, including Antarctica.
Some might even remember these dinosaurs from their brief appearance in the animation Land before time, in which the forest character Kosh just nibbles on fruit and burp contentedly. In real life, however, some families of ankylosaurs may be more picky and prefer their vegetables.
Just before Borealopelta in Alberta kicked in the bucket and was swept away by the sea, possibly by a flood, scientists say he named stems, twigs and particular species of fern, while largely ignoring the leaves of conifers and cycads, which were abundant at the time.
In fact, of all the chewed leaf material found in its intestines, 88 percent were considered fern leaves and only 7 percent were stems and twigs.
“When we looked at small sections of stomach contents under the microscope, we were shocked to see beautifully preserved and concentrated plant material,” says biologist David Greenwood of Brandon University in Canada.
“In marine rocks, we almost never see such superb preservation of the leaves, including microscopic sporangia producing fern spores.”
In total, the team found 50 types of plant microfossils, including six types of moss or liverwort, a wide variety of ferns, several types of conifers, and two flowering plants.
Among the edible content, the researchers also found gizzard stones – rocks deliberately swallowed by animals ingest to help digestion of hard materials (crocodiles and seals do this, for example).
But perhaps the most intriguing discovery is the presence of burnt vegetation, which may have been devoured by accident or potentially on purpose.
“[T]here there is considerable charcoal in the stomach from fragments of burned plants, which indicates that the animal was grazing in a recently burned area and benefitting from a recent fire and the fern hunting that is emerging frequently in a scorched landscape, “says Greenwood.
“This adaptation to a fire ecology is new information.”
If this interpretation is correct, this would represent the first evidence of the presence of large-bodied herbivores taking advantage of the regrowth of vegetation after a fire. And while it may seem incredibly niche, it affects many other lives on Earth.
Today, in modern ecosystems, large herbivores are considered crucial for the landscapes they occupy. In fact, they are often called “keystone” species because they help support the ecosystem as a whole.
“Like the large herbivores alive today, like the moose and the deer, and the elephants in Africa, these nodosaurs, by their food, would have shaped the vegetation of the landscape, possibly keeping areas more open by their pasture”, explains Greenwood.
Researchers are fairly certain that the exceptionally preserved dinosaur died soon after its last meal, but whether or not this meal is indicative of what other herbivorous dinosaurs of its time ate remains unclear.
It is, after all, only one specimen, and its diet may not reflect the typical or average diet of the individual or taxon.
Especially when you consider that this dinosaur died in late spring and mid-summer, and the diet is often linked to seasonal changes and landscape variations in the availability of food.
“These caveats aside,” the authors write, “these data represent the best direct evidence available for food in a non-avian herbivorous dinosaur.”
The chances of us finding something like this are extremely rare.
The fossilized stomach is now on display alongside the dinosaur skeleton at the Royal Tyrrell Museum in Alberta.
The study was published in Royal Society Open Science (link not yet online at time of publication).