In the beginning, the narrator states that there was no grass in the Cretaceous. Some putative grass microfossils actually were recovered since the Albian stage of the Cretaceous, however they might instead just represent basal relatives to true grasses. Regardless, true grasses are known to have existed during the Late Cretaceous, thanks to phytoliths from the Indian Lameta Formation, dating to the Maastrichtian stage. Despite grasses having been around in the Late Cretaceous period, it wasn't as widespread as it is today, and, to date, little to no evidence exists on their presence in North America at the time.
There is slight shrink wrapping on the heads of Coelophysis, Postosuchus, and Plateosaurus. In reality, the skull openings likely were not externally visible.
There is no conclusive evidence that Coelophysis was cannibalistic. This was based on a fossil of Coelophysis with jumbled-up bones in its stomach cavity, but these turned out to be species of small crocodylomorphs, rather than the juveniles they were long mistaken to be. However, this was discovered after the release of this episode, and it is not implausible, given that cannibalism is not rare in theropods.
Coelophysis may have had feathers, but this is still highly debated. Recently a study on thermoregulation of Triassic ornithodirans confirmed that Coelophysis would likely have a body completely covered in feathers, as much as any other smaller ornithodirans at the time. However, another study that aimed to calculate the body heat generated in comparison to the size of the body of different types of animals, showed that this correlation isn't always crescent and might have been highly variable in animals, including extinct ones. When translated to ornithodirans, this would ideally not be detrimental for smaller species to endure with a largely featherless skin covering and larger species to endure with dense feathers in its body, as the differences to thermoregulation in response to size differences wouldn't be as obvious. That can be exemplified by some fossil formations where small scaly dinosaurs coexist with equally small feathered dinosaurs, like Psittacosaurus which lived alongside several feathered theropods, and even large feathered dinosaurs, like Yutyrannus, implying size and the distribution of filamentous integument aren't entirely dependant on each other. In the case of Triassic ornithodirans, like Coelophysis, the presence or lack of filamentous integument may be complicated to ascertain at the end of the day. Ideally, however, given it is usually accepted that dense filamentous covering is a basal trait in dinosaurs (given basal ornithischians and small theropods are known to have had it), it's fair to assume Coelophysis probably was covered in feathers, purely due to phylogenetic relationships.
The hands of the Coelophysis should not be pronated.
Coelophysis is known to have been sexually dimorphic, with two distinct body morphs, a gracile morph that likely represents females and a more robust morph that likely represents males, being known from the vast amount of specimens of the animal. However, all the Coelophysis individuals in the episode are depicted with identical body proportions.
Coelophysis didn't evolve until 4 million years after the episode's setting.
Dinosaurs probably evolved 23 million years before the setting instead of 10, as proven by the recently discovered Nyasasaurus, said to be 243 million years old. However, whether it is classified as a true dinosaur or a close relative is still debated.
Placerias may not have been as common as depicted in the program, as Placerias remains are generally concentrated in a single area of the Chinle Formation, the Placerias Quarry, with finds of the animal outside the quarry being much rarer. The show does state that Placerias are supposed to be rare, despite the numbers shown in the program.
Placerias may have had some hair coverage on their bodies, though this is still debated. No definite proof exists of the existence of hair-like filaments in non-cynodont synapsids, but it is certainly possible dicynodonts could have had them. If so, it doesn't seem likely that the skin would be covered in a dense pelt of hair, and more recent evidence seems to support a more naked hairless skin for the group.
It is stated in the program that Placerias is "the last of its kind" and "an endangered species." However, dicynodonts actually persisted after the extinction of Placerias, with species such as Lisowicia being known from later Triassic rocks than Placerias. It was however the last dicynodont known from North America.
Placerias is called a reptile in the program, when it was actually a synapsid.
Archosaurs generally don't mark their territories with urine, unlike the male Postosuchus in the program. It's likely that, just like their crocodilian relatives, Postosuchus didn't mark their territory at all, maintaining and defending their hunting ground from intruders. However, w
