A study in Current Biology 'Repeated evolution of divergent modes of herbivory in non-avian dinosaurs' at https://doi.org/10.1016/j.cub.2019.10.050 … herbivore dinosaurs evolved many times over the 80 million years of the Mesozoic era. In other words, they adapted to changing environments and food resources in different ways, filling various niches. Whilst they all did not evolve to chew, swallow, and digest their food in the same way, certain specific strategies appeared time and again. See https://phys.org/news/2019-12-dull-teeth-skulls-specialized-evolved.html
At https://phys.org/news/2019-12-cretaceous-mammal-evidence-modules.html … Chinese scientists in both the US and China report on a new symmetrodont, the Origdestes, a stem therian mound from Early Cetaceous sediments. The fossil animals concerned died at rest, we are told, curled up in a den or burrow while asleep. This meant the skeleton was itself undisturbed, but huddled up for warmth.
… Other fossil animals at the same site, the Lujiatun beds in Liaoning Province, are also preserved while asleep (at point of death and burial), and includes dinosaurs.