Dimetrodon () was a predatory synapsid (mammal-like "reptile") genus that flourished during the Permian period, living between 280 and 260 million years ago. It was more closely related to mammals than to true reptiles (Sauropsida) like dinosaurs, lizards and birds.
Dimetrodon was not a dinosaur, despite being popularly grouped with them; rather, it is classified as a pelycosaur. It is surprisingly well known to the general public: it makes an appearance in the James Mason film Journey to the Center of the Earth.
Characteristics
Dimetrodon was a
dominant carnivore, the largest of its day. It grew to up to 3 meters (10 feet) in length. The name
Dimetrodon means 'two-measure teeth'; it is so named because it had a large skull with two different types of teeth (shearing teeth and sharp canine teeth), unlike reptiles. It walked on four side-sprawling legs and had a large tail.
Dimetrodon may have moved in a manner similar to present-day
lizards.
Sail
The most distinctive characteristic of
Dimetrodon was the spectacular sail on its back. The sail was probably used to regulate body temperature; the surface area would allow it to warm up or cool off more efficiently. It may also have been used in mating rituals and to ward off other
predators. The sail was supported by neural spines, each one sprouting from an individual
vertebra.
Relationship with modern mammals
As a synapsid,
Dimetrodon was distantly related to
humans and all other modern mammals.
Synapsids were the first 'reptiles' to evolve differentiated
teeth. Whereas
reptiles hardly chew their food, simply gulping it down, synapsids like
Dimetrodon developed teeth to help shear meat into smaller pieces for easier ingestion. These 'two-measure teeth' eventually gave rise to the various kinds of teeth present in modern mammals. For more information on human ancestry, see
timeline of human evolution.
In popular culture
- In the television documentary Walking With Monsters (called Before the Dinosaurs in the U.S.), baby Dimetrodon were shown hatching with sails, fully independent. In fact, no Dimetrodon eggs have yet been found, and it's entirely possible that the sail, which would be hard to store in an egg, was either absent or not rigid upon hatching. The program also stated that Dimetrodon consumed 90% of a carcass, while lions today ate 70%, and that Dimetrodon would only eat intestines after shaking out the waste inside, since "dung is one thing a Dimetrodon can't stomach." Hatchlings also had to sprint towards trees after hatching in order to escape cannibalistic adults. These behaviours seem to be based on the Komodo Dragon and thus attributing them to Dimetrodon is an almost entirely speculative move on the part of the originators, who have presented the characteristics as "fact" rather than speculation in order to heighten the sense of realism.
- Dimetrodon is often mistaken for Spinosaurus, due to the fact that they both have 'sails'. Spinosaurus however, was a dinosaur and bipedal, whereas Dimetrodon was not a dinosaur and was quadrupedal.
- Dimetrodon is often included in dinosaur toy sets, despite the fact that it was not a dinosaur.
- In Dino Thunder, one of Black Ranger's zords was a Dimetrodon.
External links
Pelycosaurs | Permian animals
Dimetrodon | Dimetrodon | Dimetrodon | Dimétrodon | Dimetrodon loomisi | דימטרודון | Dimetrodon | Dimetrodon | ディメトロドン | Dimetrodonte | Dimetrodon