- "Running into a Dimetrodon in Jurassic Park would have been an interesting experience - and a dangerous one!"
- —Kenner collector card([[|src]])
Dimetrodon was a pelycosaur, one of a number of animals known as Mammal-Like Reptiles (more accurately synapsids) that dominated the Late Permian period. It was a large meat-eater that lived primarily in swampy areas and had a very interesting feature - a large sail on its back. Although often mistaken for a dinosaur, it died out long before dinosaurs evolved and is more closely related to modern mammals.
Unlike other pelycosaurs that did not have fins, Dimetrodon was able to warm up in the morning and cool off more efficiently during the heat of the day due to its sail. This method of controlling its body temperature, along with its large and powerful jaws, gave this predator a distinct advantage over the other large carnivores, making it the dominant land predator. In fact, its ability to warm up faster would have enabled it to catch and eat the slower, non-finned Mammal-Like Reptiles.
Dimetrodon is easily distinguished from dinosaurs as its legs were positioned on the side of its body while dinosaurs had their legs under their bodies. Even with this body structure, it was probably a very fast runner. It had a large head with very strong jaws and two types of teeth -sharp fang-like teeth for ripping and tearing in the front and smaller cheek teeth in the back that were designed for shredding the meat. 
This information stood on the collector card from the Kenner toyline:
'Scientists once speculated that Dimetrodon's unique dorsal structure was used as a sail to help the animal swim. Now, however, the more widely accepted explanation is that the spines were involved in regulating body temperature, as blood flowing through the sail could be warmed or cooled more quickly than in the rest of the body.'
Dimetrodon itself doesn't appear in the movies, although a statue of Dimetrodon is seen in Benjamin Lockwood's museum in the Lockwood Manor in Jurassic World: Fallen Kingdom. The statue of Dimetrodon has osteoderms like crocodiles, the skin in the sail are more extensive than the original, the head is more box-shaped and lacks the notch the real animal had in the top jaw.
Dimetrodon appears on the alternative cover of Jurassic Park: Redemption III. A green Dimetrodon is sitting on a blue car in a car lot. This event never happens in the comic series.
Dimetrodon appears in Jurassic Park: Redemption II, though it is only seen in two images. Dimetrodon is one of the many new species of prehistoric animals that is intended to be in the new Jurassic Park that Tim Murphy and the “unknown” investor created.
Even though Dimetrodon is a carnivore, it’s seen eating the hay that is in its pen. This is one of the many scientific inaccuracies in Jurassic Park: Redemption. This suggests that it may instead be an Edaphosaurus, an herbivorous relative of Dimetrodon or some herbivorous pelycosaur although it more closely resembles Dimetrodon.
Dimetrodon is an enemy in the Jurassic Park (NES game).The Lost World: Jurassic Park: Be on careful lookout for Baryonyx, Barasuchus, and Dimetrodon. Later it is shown in the intro of the raptor level, Dimetrodon is said to be a prey of Velociraptor.
Dimetrodon was also going to make an appearance, in the InGen Complex of the Human Hunter level. However, they were replaced by the Deinonychus according to the Raptor Gallery. Dimetrodon does appeare in the T. rex intro.
Dimetrodon is a Carnivore that can be created from DNA in Jurassic Park III: Park Builder.
Dimetrodon is a legendary carnivore in the IOS game, Jurassic World: The Game.
see Dimetrodon/JW: A
Dimetrodon appears in Jurassic World: Alive, with the GEN 1's appearance based on the statue from the film.
A 15 centimetres long, the Dimetrodon action figure appeared in the Kenner's Jurassic Park Series 1. Together with a JP-Card, this Dimetrodon looks very good both in details and sculpture, though the legs are, however a bit short. The same figure was repainted for Jurassic Park: Dinosaurs. Its paint job is green with grey markings and yellow spots on its sail. This paint job is excellent for hunting in dense forests, with the green to blend in with the vegetation and the grey markings to simulate shadows, while the yellow spots could pass for patches of sunlight shining through the trees. This paint job suggests that tropical forest or a swamp was the creature's intended habitat.A collector card came with this figure. Its picture shows alan Grant and Ellie who encounter a Dimetrodon in the jungles of Isla Nublar. The text on the back says: Running into a Dimetrodon in Jurassic Park would have been an interesting experience - and a dangerous one!
A Dimetrodon figurine appears in the Die-Cast: Jurassic Park toy line. The figure came with a collector card. It shows Alan Grant, Ellie and Lex struggling with a Dimetrodon.
A repaint of the Series 1 Dimetrodon appears in the Jurassic Park: Dinosaurs toy line.
The same Dimetrodon figure also appears in the Jurassic Park: Dinosaurs Hybrids toy line. This version has a very swamp like paint job suggesting that it hunts in swamps.
A cyan version of the Dimetrodon appears in the Jurassic Park: Dinosaurs 2 toy line. It comes with an action figure of a diver, indicating that Dimetrodon is meant to be an aquatic creature much like the Spinosaurus in JPIII. This is semi-plausible, since Dimetrodon is thought to have lived in vast wetlands.
Jurassic World: Fallen Kingdom LEGO set
A 2019 line from Mattel will feature Dimetrodon. This coloration seems to be based off of the diorama in the Lockwood Manor.