An article published in the journal “Royal Society Open Science” reports a study on the last meal of the only known specimen of Borealopelta markmitchelli. The exceptional conservation of this armored dinosaur fossil, a nodosaurid ankylosaur, has also made it possible to find what is by far the best-preserved dinosaur stomach discovered so far. This allowed a team of researchers to examine this stomach and its contents, a mass the size of a soccer ball. The result is definitive evidence of the diet of these herbivorous animals and offers much more information on the interaction with their environment than just the skeleton.
During the Mesozoic era, the so-called megaherbivores, which are herbivores with a mass greater than one 1,000 kg, were dinosaurs. Today, however, that niche is occupied by mammals that have enormous effects on the environment in which they live, and for this reason they’re called keystone herbivores. Megaherbivore dinosaurs lived for a much longer time than their mammalian equivalents since they existed for about 150 million years whereas mammals have existed for about 40 million years, and had a far bigger mass since several species had masses of tens of tons.
Today it’s difficult to evaluate the impact that those megaherbivores had on the Mesozoic environment because the diet of the various species is generally deduced from the available flora and nutritional contents, from the connection between dinosaurs and plants in the various environments, from the biomechanics of their jaws, from teeth consumption, from posture and feeding height, and stable isotopes. The many differences between dinosaurs and mammals make comparisons difficult and direct data are few. For this reason, having a Borealopelta markmitchelli specimen exceptionally preserved to the point of including the last meal is very useful.
An article published in August 2017 in the journal “Current Biology” reported a study on the only available specimen of Borealopelta markmitchelli. Subsequently, a team of researchers with various members in common with the previous one examined its stomach contents and found interesting information. 88% of that meal consists of chewed leaves and 7% of stems and twigs. A microscopic examination of the contents revealed the presence of other plant materials which are also in an exceptional state of conservation that include 48 palynomorphs, which are tiny fossils of pollen and spores, including moss and liverwort, 26 clubmosses and fern flowers, 13 gymnosperms (mainly conifers) and two angiosperms (flowering plants).
The extraordinary preservation of that Borealopelta markmitchelli’s last meal offers various information. This dinosaur’s misfortune became after about 110 million years an opportunity to understand something more about this ankylosaur and the environment in which it lived. This specimen must have died shortly after its last meal allowing its contents to preserve. The researchers were able to evaluate direct evidence of this animal’s diet, deducing from the type of plants eaten that it died between the end of spring and mid-summer.
The study of the Borealopelta markmitchelli specimen will continue because many paleontologists are interested in obtaining all possible information about it and the plants it ate. Such well-preserved fossils truly represent a treasure for researchers by offering direct and accurate information about their life and the environment in which they lived.
