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.
- 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!
- Dennis the Menace (UK): At least one strip features a caveman version of Dennis, accompanied by a sabre-toothed Gnasher.
- Garfield: His 9 Lives: The "Cave Cat" segment shows Garfield as a saber-toothed housecat and Odie as a giant green saber-toothed dogsaurus.
- "Valley of the Dildosaurs", a 1975 NSFW comic parodying dinosaur 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!"
- The Beast from 20,000 Fathoms: The Rhedosaurus is a massive carnivorous dinosaur that moves around on four legs and has no trouble hanging out at the bottom of the ocean.
- The Giant Behemoth: The eponymous behemoth is called a Paleosaurus. It has the quadrupedal stance and long neck of a sauropod, sharp teeth and claws of a theropod, and crocodile-like scaly skin.
- Godzilla: The films use this trope as a frequent explanation for its Kaiju, Hand-Waving their enormous size and apparently supernatural abilities by saying that they simply aren't on the fossil record and thus anything goes.
- Godzilla himself is sometimes described as a dinosaur called a "Godzillasaurus" that mutated and grew to massive size due to exposure to radiation in the 1950s, but other times, like in the original film and the MonsterVerse continuity, it's made clear that he was always that big.
- Anguirus somewhat resembles an Ankylosaurus but far, far larger. His head horns are similar to those of ceratopsians as well.
- Rodan is either a colossal and very fictional relative of the Pteranodon or another atomic mutation depending on the continuity, much like Godzilla. In the MonsterVerse setting, he's stated to be an ancient superspecies hailing from the Permian period, meaning he isn't even a pterosaur at all, but something similar and far older predating the entire pterosaur order by millions of years!
- Baragon is a quadrupedal dinosaur that can burrow through the ground like a mole and breathe fire. Although he's a fraction of Godzilla's size he's still much larger than any real dinosaur. Strangely, he's got a pair of mammalian-like ears, which has led some fans to consider him a synapsid instead.
- Gorosaurus is essentially a Kaiju-sized Tyrannosaurus with no special abilities. He can use his prehensile tail and powerful legs to deliver a nasty kangaroo kick, however. Some official sources claim he is a descendant of Allosaurus.
- Likewise, Titanosaurus is a massive semi-aquatic dinosaur that resembles a Spinosaurus, with large sails on his back and a long, crocodile-like snout. Note that there is an actual dinosaur called Titanosaurus that bears no relation. note
- 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, she 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. Jurassic World: Fallen Kingdom then takes the Indominus template and applies it to a Raptor Attack, creating the Indoraptor.
- A Sound of Thunder: The film has baboonasaurs, flying batasaurs and the claim that lions are somehow descended from allosaurs.
- After Man: A Zoology of the Future: Has saber-toothed weasels and monkeyraptors.
- Geronimo Stilton: Particularly painful puns (especially if you know Greek and/or Latin) pepper the pages of the Cavemice books. Notable examples include Autosaurus (which would mean "self reptile"), a type of dinosaur that's used as a car equivalent, and Octosaurus ("eight lizard"), which isn't even a dinosaur at all, but a giant octopus.
- Man After Man: An Anthropology of the Future has saber-toothed humans and ground slothmen.
- 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).
- 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).
- Eberron has 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 instantly mocked the moment it was published.
- In Warhammer, one Lizardmen subrace is known simply as "Saurus". Among their Beasts of Battle are such creatures as the Stegadon ("roofed tooth"), the Terradon ("earth tooth", for a toothless flying creature) and the Carnosaur ("meat lizard", a generic name for meat-eating dinosaurs). The Bastiladon, a pseudo-ankylosaur, is actually given a very appropriate name meaning "fortress lizard". More explicitly made-up creatures include the spike-covered Razardons and the cave-dwelling, eyeless Troglodons.
- Dragon Quest:
- Dragon Quest VI includes an axe-wielding dragon monster called a Hackasaurus. One can even join your party.
- One of the Bonus Bosses in Dragon Quest IX is Tyrannosaurus Wrecks.
- Dragon Quest XI has some magic-wielding scholar dragons as monsters; with the earliest version you encounter being called a Professaurus.
- 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".
- 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.
- 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.
- 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 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).
- 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.
- Eek! The Cat: The "Terrible Thunderlizards" segment often uses this. Like a porcupinosaurus, for example.
- 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".
- The Future Is Wild features a saber-toothed wolverine, a caracararaptor, and a turtlesaurus (specifically named a snowstalker, carakiller, and toraton).
- Ice Age: Scrat 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.
- Johnny Test: The catsaurus and catdactyl on Bling-Bling's Island .
- Looney Tunes: "Prehistoric Porky" shows Porky to be descended from a cavepig, while "Pre-Hysterical Hare" shows Bugs to be descended from a saber-toothed rabbit.
- My Little Pony:
- My Little Pony 'n Friends: In "Woe Is Me, Part 1", Woebegone is introduced fleeing from the latest victim of his misfortune, an alligatorsaur, depicted as a very large, draconic reptile.
- My Little Pony: Friendship Is Magic: The Cold Opening for "The Fault in Our Cutie Marks" has a filly named Petunia Paleo, a paleontologist pony note , discover the remains of a "spiny-backed ponysaurus", whose bones resemble a regular horse's with a row of spikes running down its head and neck.
- Phineas and Ferb: "The Tri-Stone Area" has Perry as a saber-toothed platypus.
- SpongeBob SquarePants:
- Tom and Jerry: "Prehisterics" has Tom as a saber-toothed housecat and Jerry as a cavemouse. During the short they encounter a giant saber-toothed rabbit.
- 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".