Many works are set in 1 Million B.C. However, some works just do a few episodes in prehistory, while mostly in other eras. When this happens, they usually have a prehistoric animal be an ancestor of the characters in the show.
However, most writers only know a few types of dinosaur. When they don't think they can pass off any of them as the ancestor of their character, they tend to use either "Xsaurus", "Xdactyl", "X. rex", "Xraptor" or similar naming schemes to quickly create a new species of dinosaur, filling in the template with any word that seems relevant to the beast in question or just looks cool. "Saber-toothed X", "Woolly X" and "Cave X" are also used in a similar manner, usually by sticking the descriptors in front of any given species of modern animal to create an ice age-themed version of its species. May also sometimes occur in modern-day set dramas involving mutated animals.
Funny Animal characters are usually neanderthals (or what fiction tends to think neanderthals were like) unless they are antagonists.
- The "Cave Cat" segment of Garfield: His 9 Lives shows Garfield as a saber-toothed housecat and Odie as a giant green saber-toothed dog.
- Atomic Robo:
- In one of the Free Comic Book Day issues, Dr. Dinosaur manages to make a cyborg Tyrannosaurus that he dubs a "Futuresaurus Rex".
- In a later FCBD issue, he makes a killer "Omnisaur" - half Triceratops, half Ankylosaurus, and half Stegosaurus.
Robo: Aren't those herbivores?
Dr. Dinosaur: [to Omnisaur] You were supposed to tell me everything!
- An 1975 underground comic "Valley of the Dildosaurs" (NSFW - duh), parodying all the Dino movies (of course mainly "Valley Of The Dinosaurs"), even goes on a lampshading tangent: "Yes, we know that Hornysaurus and Vibratodon never lived at the same time!"
- A number of Syfy movies. Case in point: Dinocroc.
- Insectosaurus from Monsters vs. Aliens.
- The film version of A Sound of Thunder has baboonasaurs, flying batasaurs & the claim that lions are descended from allosaurs.
- The plot of Jurassic World sees the park shift from reviving known dinosaurs to engineering one of their own, called Indominus rex. Claire explains to Owen that they chose the name to sound scary and be easy to remember, as complex names weren't popular with the public. In earlier drafts of the script, it was going to be called Diabolus rex. A Stegoceratops (Stegosaur/Triceratops hybrid) was also going to be in the movie, but was scrapped so that the I. rex would be the only specially engineered beast.
- Godzilla's original form in Godzilla vs. King Ghidorah was a fictitious dinosaur known as a Godzillasaurus before his exposure to the radiation that formed him into the 100-meter monster known to Japan.
- After Man: A Zoology of the Future has saber-toothed weasels and monkeyraptors
- Man After Man: An Anthropology of the Future has saber-toothed humans and ground slothmen.
- The book "Science Made Stupid", a parody of children's science books, has a Puppisaurus in a sidebar about mammal-like reptiles (the group did exist, albeit as a group of animals increasingly closely related to true mammals, but it didn't include a Puppisaurus).
- Similar puns fill up the out-of-print children's book, "Dodosaurs: Dinosaurs That Didn't Make It".
- Super Sentai and Power Rangers:
- In Power Rangers Time Force, the Quantum Ranger had a dinosaur mecha called the Quantasaurus Rex, or Q-Rex for short. The Mirai Sentai Timeranger version was simply the V-Rex. Power Rangers Megaforce would later recycle the Q-Rex name for its dino mecha in homage to the original.
- Bakuryuu Sentai Abaranger plays on the Japanese word for dinosaur(s), "kyoryu"; calling their dino-like mecha "bakuryu" ("blastosaurs").
- Power Rangers Dino Thunder called its main mecha combination the Thundersaurus Megazord. One episode also had the Rangers' class at a paleontology dig, and when Kira tried to get Dr. O's attention she claimed that she found a "morphasaurus" fossil.
- Kishiryu Sentai Ryusoulger does a similar wordplay as Abaranger, naming their mecha "kishiryu" ("knightosaurs"). It also involves two made-up species, a "Needlesaurus" (a stegosaurid) and a "Tigersaurus" (a reptilian version of a Smilodon, as opposed to the real-life mammal).
- In Warhammer, one Lizardmen subrace is known simply as "Saurus". Among their Beasts of Battle are such creatures as the Stegadon, the Terradon and the Carnosaur.
- Eberron had a number of made-up dinosaurs to go with the regular dinosaurs found in the setting. Most were poorly received, being thought as silly, but the Battle Titan Dinosaur, thanks to looking mostly like it was put together by giving a chimpanzee a tub of glue and a box of random fossils (or maybe two tubs of glue, only it sniffed the first one) got it the worst, becoming instant Snark Bait the moment it was published.
- Teenage Mutant Ninja Turtles: Turtles in Time has a reference to this in the prehistoric level, called "Prehistoric Turtlesaurus". No actual tutlesaurus appear, but funny enough, you fight Slash (who kind of looks the part) as a boss in the SNES port.
- Pokémon: The very first family in the Pokédex is a line of dinosaur/plant hybrids named Bulbasaur, Ivysaur, and Venusaur. Aerodactyl is also a cross between a gargoyle or a wyvern and a pterodactyl. Later games add a sabertoothed dinosaur named Haxorus.
- Fossil Fighters calls its revived dinosaurs-and-other-beasts "Vivosaurs". There are also undead Vivosaur variants, "Boneysaurs" and "Zombiesaurs"; as well as made-up species like "Frigisaurus", "Ignosaurus", and "Saladasaurus".
- In Fossil Fighters Frontier, you're given a genetically engineered dinosaur as your partner that changes forms throughout the game. It starts as a "Nibblesaurus", then becomes a "Munchasaurus" and a "Chompasaurus". Its final form averts this trope, instead going by the name "Crimson Ravager".
- Xenoblade Chronicles X: One of the common indigens that roams the planet Mira are sauropod-like Millesaurs.
- Yooka-Laylee includes a dinosaur character that's a throwback to the days of 64-bit gaming, named Rextro Sixtyfourus.
- The Flintstones sometimes makes vague references to creatures like a "chickensaurus". Additionally, Dino is apparently called a "snorkasaurus", while Hoppy is a kangaroo-like creature called a "hoppasaurus".
- Scrat from Ice Age is a saber-toothed squirrel. He is somewhat inspired by Leptictidium, an actual small, hopping prehistoric mammal with a long snout, but the similarities end there. Since the release of the movie, another prehistoric mammal, Cronopio, was discovered to be even more similar to Scrat.
- The Future Is Wild features a saber-toothed wolverine, a caracararaptor, and a turtlesaurus (specifically named a snowstalker, carakiller, and toraton).
- The Looney Tunes short "Prehistoric Porky" shows Porky to be descended from a cavepig, while "Pre-Hysterical Hare" shows Bugs to be descended from a saber-toothed rabbit.
- The Tom and Jerry short "Prehisterics" has Tom as a saber-toothed housecat and Jerry as a cavemouse. During the short they encounter a giant saber-toothed rabbit.
- SpongeBob SquarePants:
- The episode "Ugh" has Spongebob, Patrick, and Squidward as a cavesponge, caveoctopus, and cavestarfish, with Gary as a giant snailsaurus.
- 'The Spongebob Movie Sponge Out Of Water has a Squidosaurus which is a cross between Squidward and a Tyrannosaurus rex''.
- Dino Squad has many examples. Most of the mutated creatures created by Victor Veloci were mutated mixes of modern day and ancient creatures. Only the Dino Squad were 'perfect' creatures.
- The Phineas and Ferb episode "The Tri-Stone Area" has Perry as a saber-toothed platypus.
- The catsaurus and catdactyl on Bling-Bling's Island on Johnny Test.
- The "Terrible Thunderlizards" segment of Eek! The Cat often uses this. Like a porcupinosaurus, for example.
- The Croods is all about this, where aside from a sloth, the film has prehistoric fauna of colorful Mix-and-Match Critters; the one with most screentime is a "Macawnivore", a sabre-tooth tiger colored like a macaw (nicknamed Chunky).
- In My Little Pony: Friendship Is Magic, Petunia Paleo, a paleontologist pony note discovers the remains of a "spiny-backed ponysaurus".
- In reality, many prehistoric animals seem like this, for example, ceratopsids (rhinosauruses), sauropods (giraffesauruses), pterosaurs (batsauruses), ichthyosaurs (dolphinsauruses), ornithomimids (ostrichsauruses), spinosaurids (crocodilesauruses), Dinofelis (saber-toothed leopard), etc. Subverted, since they aren't ancestors of the similar modern-day creatures.
- Some prehistoric creatures are named this way (but the X part is almost always in another language), such as Nanuqsaurus (polar bear lizard) and ichthyosaurs (fish lizards). An interesting aversion is Struthiosaurus, which means "ostrich lizard" but looked like this◊. Among mammals, there is an unofficial naming convention among the saber-toothed cats where different groups are named after different cutting weapons — the two main ones are Smilodon and its relatives, called the dirk-toothed cats, and the shorter-fanged scimitar-toothed cats.
- Reptiles filmed using perspective tricks to look like giant monsters are nicknamed "Slurpasaurs".