Trivia / March of the Dinosaurs

• Falsely Advertised Accuracy: Not too much with the dinosaurs, but the two non-saurians have rather questionable portrayals.
  • Quetzalcoatlus is portrayed as a biped, even though pterosaur trackways unambiguously confirmed that these animals walked on all fours back in the early '90s (after initially being misinterpreted as crocodylomorphs tracks), and yet this documentary came out in 2011. Pterosaurs being quadrupeds is a very basic thing a paleo-documentary should know. And despite both the Troodon and the tyrannosaurs being portrayed as feathered, the pterosaurs are still naked (even though we knew that they had pycnofibers since the '70s)
  • The mosasaur Prognathodon is portrayed as being able to alternate between salt and freshwater, and the climax of the story has a large number of them congregate at a river to hunt the crossing duckbills and ceratopsids, in a clear homage to Nile crocodiles hunting migrating zebras and wildebeests. While we have some evidence of small derived mosasaurs such as Platecarpus and Clidastes occasionally entering freshwater based on isotope analyses, there is no such evidence for larger mosasaurs, and furthermore, despite being reptiles, mosasaurs were physically and ecologically analogous to pelagic sharks and toothed whales such as orcas, not crocodiles. Them opportunistically attacking the Edmontosaurus while the latter are crossing a frozen sea inlet isn't too improbable (akin to orcas attacking swimming moose) but the second scene where the mosasaurs go full crocodile is very far-fetched.
• Science Marches On:
  • The basic plot probably wouldn’t have happened in real life, as Arctic dinosaurs likely didn’t migrate during the winter, or at least nowhere near as extensively as shown here. Part of the reason behind this theory was that, at the time, the Edmontosaurus and Pachyrhinosaurus found in Alaska were assumed to be the same species as the ones found further south in Alberta, but not long after the film aired, the former were reclassified as being separate species from their southern cousins (with some even considering the polar edmontosaur a separate genus, Ugrunaaluk), along with several other lines of evidence suggesting that hadrosaurs and ceratopsians didn’t travel much.
  • The Alaskan tyrannosaur is depicted as a Gorgosaurus, an albertosaurine (gracile tyrannosaur) who lived in Alberta several million years prior, but in 2014, it was discovered that the former was a previously unknown species dubbed Nanuqsaurus, who also turned out to be a tyrannosaurine (robust tyrannosaur), meaning it would have more closely resembled a Daspletosaurus than a Gorgosaurus.
  • The Quetzalcoatlus is depicted with a robust, blunt bill, a semi-common depiction of the animal at the time and inspired by one specimen◊ from Texas, but in 2021, the specimen was recognized as a completely different azhdarchid, called Wellnhopterus, and the real Quetzalcoatlus had a much thinner bill◊. It’s also depicted as a vulture-esque scavenger but subsequent studies showed that it was a terrestrial predator of small animals (akin to a stork), though it would have still scavenged dead dinosaurs when given the opportunity.
  • The Prognathodon, in general, has aged very poorly. Even ignoring the fact that it’s shown living in freshwater, it’s depicted as incredibly skinny and has the classic paddle-shaped tail, but later finds showed that mosasaurs were much more compact animals with crescent-shaped tail flukes (akin to a shark). At least the shark-like colorations are on point.
  • Prognathodon has more recently been cited by many workers as a wastebasket taxon, and the North American species, Prognathodon overtoni, would more accurately be called Brachysaurana overtoni.
  • Same for the Troodon. While its behavior is mostly plausible, its plumage is very minimalistic, with a naked face and no wings. Furthermore, Troodon itself has been deemed a dubious genus in 2017 (due to its holotype being just teeth, which are undiagnostic on a generic level) and the giant Alaskan troodont was likely a completely different animal.
  • The feathered Gorgosaurus and Albertosaurus. Evidence of feathered tyrannosaurs first came about with the 2004 description of the small, basal tyrannosaur Dilong paradoxus, and gained further traction just one year after the film aired, with the description of the 9-meter long but still basal Yutyrannus huali. However, a 2017 study reviewing known skin impressions of various derived tyrannosaurids, including those of the T. rex specimen nicknamed "Wyrex" (BHI 6230) which preserves patches of mosaic scales on the tail, hip, and neck, suggests derived tyrannosaurids likely had very little to no feathering. Specimens of Gorgosaurus itself have also preserved patches of small, rounded or hexagonal scales, and given its close phylogenetic relationship to T. rex, it’s unlikely that it and Albertosaurus were extensively feathered, despite being descended from feathered ancestors.
  • A few years after the movie aired, a preserved fleshy crest in Edmontosaurus regalis, the species portrayed here, was discovered.
  • At the time the movie was created, it was believed that the manus of hadrosaurs had no claws. However, in 2019, it was discovered in the Edmontosaurus annectens "mummy" that hadrosaurs had two nails on their front feet: a hoof-like one on the third digit and a spade-shaped one on the second.