Trivia / Walking with Monsters

• Accidentally-Correct Writing: The penultimate segment (Late Permian) shows a giant Siberian gorgonopsid (Inostrancevia by all accounts) coexisting with the South African Rhinesuchus and Diictodon (the northernmost fossils of the latter are from China). Fast forward to 2023, and we described a new species of Inostrancevia called I. africana from... yup... South Africa.
• Falsely Advertised Accuracy: An unfortunate example is the giant Carboniferous spider, thanks to some very bad timing. The spider was supposed to be Megarachne, who (as the name implies) was envisioned as a giant spider since the '80s, but while WWM was in production, a second, more complete specimen of Megarachne was described and revealed that the animal was actually a misidentified eurypterid. As the animation was already completed, the producers simply rebranded Megarachne as an indeterminate mesothelian, an extant group of spiders whose fossil record goes all the way back to the Late Carboniferous, but there is no evidence that any of them grew anywhere near as big as Megarachne, thus making the Carboniferous spider in this series an entirely fictional animal.
• Re-Cut: The program originally aired as a 90-minute TV movie, and then as three half-hour episodes with small cuts made throughout. Discovery Channel used the movie version for their American dub, but the regular DVD release uses the episodic version. In the UK, the movie version was later released on DVD as a Reader's Digest edition.
• Science Marches On: The show uses the older classification system where land vertebrates are divided into amphibians (must lay eggs in water), birds, mammals, and reptiles, where reptiles include any land vertebrates not in the other groups. Biology has switched to phylogenetic systems where groups are defined by having a common ancestor. "Amphibian" is technically not a group in this system, but like "fish" is still useful to describe creatures with certain characteristics. The "mammal like reptiles" on the show are no longer called that, or called reptiles, instead "synapsid" is the official name. "Reptile" is reserved for diapsids, the other descendants of vertebrates with hard shelled eggs, to avoid including mammals and better match the word's everyday meaning.
• The Other Darrin: Mark Halliley narrates the Making Of documentary, not Kenneth Branagh.
• Word of God: Confusingly, the tie-in book (The Complete Guide to Prehistoric Life) identifies the giant gorgonopsid as Gorgonops, a dog-sized gorgonopsid from South Africa, even though its large size and living alongside Scutosaurus in Siberia just before the Great Dying strongly suggest that it’s meant to be Inostrancevia (which was already known since 1922).^note  Though Scutosaurus and Inostrancevia are now thought to have lived several million years before the Great Dying.

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