Dimetrodon

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Dimetrodon

Dimetrodon (meaning "two measures of teeth") was a predatory synapsid

Synapsid

Synapsids , also known as theropsids , are a class of animals that includes mammals and everything closer to mammals than to other living amniotes....
('mammal-like reptile') genus

Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
that flourished during the Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Roderick Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian system" after the ancient kingdom...
Period, living between 280–265 million years ago. It was more closely related to mammal

Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
s than to true reptile

Reptile

Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded vertebrates that have skin covered in scale as opposed to hair or feathers....
s such as lizard

Lizard

Lizards are a large and widespread group of squamate reptiles, with nearly 5,000 species, ranging across all continents except Antarctica as well as most oceanic island chains....
s.

Dimetrodon was not a dinosaur

Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
, despite being popularly grouped with them. Rather, it is classified as a pelycosaur

Pelycosaur

The pelycosaurs were primitive Late Paleozoic synapsid amniotes. Some species were quite large and could grow up to 3 meters or more, although most species were much smaller....
. Fossils of Dimetrodon have been found in North America

North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
and Europe

Europe

Europe is, conventionally, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural , the Caspian Sea, and by the Caucasus Mountains to the southeast....
, as well as a significant discovery of Dimetrodon footprints in southern New Mexico

New Mexico

New Mexico is a U. S. State located in the Southwestern United States of the United States. Inhabited by Native Americans in the United States populations for many centuries, it has also has been part of the Spanish Empire viceroyalty of New Spain, part of Mexico, and a U.S....
by Jerry MacDonald.

imetrodon was an apex predator

Apex predator

Apex predators are predators that, as adults, are not normally preyed upon in the wild by other large animals in significant parts of their range....
, among the largest of its day.

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Description

Dimetrodon was an apex predator

Apex predator

Apex predators are predators that, as adults, are not normally preyed upon in the wild by other large animals in significant parts of their range....
, among the largest of its day. It grew to up to in length. The name Dimetrodon means 'two-measures of teeth', 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 lizard

Lizard

Lizards are a large and widespread group of squamate reptiles, with nearly 5,000 species, ranging across all continents except Antarctica as well as most oceanic island chains....
s.

Sail

The most distinctive characteristic of Dimetrodon was the spectacular sail on its back (other pelycosaurs such as Edaphosaurus
Edaphosaurus

Edaphosaurus was a primitive herbivore pelycosaur. Along with the Diadectidae, Edaphosaurus is one of the earliest known plant-eating tetrapods ....
, Ianthasaurus
Ianthasaurus

Ianthasaurus was a small edaphosauridae from the Late Pennsylvanian. Ianthasaurus lacks many of the spectacular specializations seen in Edaphosaurus....
, and Sphenacodon
Sphenacodon

Sphenacodon was a pelycosaur that was about in length. Sphenacodon belongs to the family Sphenacodontidae, a lineage that was related to the therapsids....
also have this trait). The sail, which was dense with blood vessels, was probably used to regulate body temperature; the surface area would allow it to warm up or cool off more efficiently. This adaptation was important because it would give the animal more time to hunt prey. The sail may also have been used in mating rituals and to warn off other predators. The sail was supported by neural spines, each one sprouting from an individual vertebra

Vertebra

A vertebra is an individual bone in the flexible column that defines vertebrate animals. The vertebral column encases and protects the spinal cord, which runs from the base of the cranium down the dorsal side of the animal until reaching the pelvis....
. Bramwell and Fellgett (1973) calculate that a 200 kg Dimetrodon would heat up from 26° C to 32° C in 205 minutes without a sail and in only 80 minutes with a sail.

Relationship with modern mammals

As a synapsid, Dimetrodon was distantly related to modern mammals. Synapsid

Synapsid

Synapsids , also known as theropsids , are a class of animals that includes mammals and everything closer to mammals than to other living amniotes....
s were the first tetrapod

Tetrapod

Tetrapods are vertebrate animals having four feet, legs or leglike appendages. Amphibians, reptiles, dinosaurs/birds, and mammals are all tetrapods, and even the limbless snakes are tetrapods by descent....
s to evolve differentiated (or heterodont) teeth. Whereas reptile

Reptile

Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded vertebrates that have skin covered in scale as opposed to hair or feathers....
s 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.

In popular culture

In many popular culture references, Dimetrodon is often erroneously seen as a dinosaur or as living alongside dinosaurs.

A composite of Edaphosaurus
Edaphosaurus

Edaphosaurus was a primitive herbivore pelycosaur. Along with the Diadectidae, Edaphosaurus is one of the earliest known plant-eating tetrapods ....
and Dimetrodon fossils went on display in 1907 in the American Museum of Natural History

American Museum of Natural History

The American Museum of Natural History , located on the Upper West Side, Manhattan, New York, USA, is one of the largest and most celebrated museums in the world....
, New York, presented by the curator of vertebrate paleontology Henry Fairfield Osborn

Henry Fairfield Osborn

Henry Fairfield Osborn was an United States geologist, paleontologist, and Eugenics, "a first-rate science administrator and a third-rate scientist."...
and illustrated in the pages of Scientific American
Scientific American

Scientific American is a popular science science magazine, published since August 28, 1845, making it one of the oldest continuously published magazines in the United States....
(May 1907) as "Naosaurus", by the great scientific illustrator Charles R. Knight

Charles R. Knight

Charles Robert Knight was an United States artist best known for his influential paintings of dinosaurs and other prehistory animals. His works have been reproduced in many books and are currently on display at several major museums in the United States....
.

In the television documentary Walking With Monsters
Walking with Monsters

Walking with Monsters is a three-part British documentary film series about life in the Paleozoic, bringing to life extinct arthropods, fish, amphibians, synapsids, and reptiles....
(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. Hatchlings were portrayed sprinting towards trees after hatching in order to escape cannibalistic adults, behaviors based on the modern Komodo Dragon

Komodo dragon

The Komodo dragon is a species of lizard that inhabits the islands of Komodo , Rinca, Flores, and Gili Motang in Indonesia. A member of the monitor lizard family , it is the Largest organisms#Reptiles , growing to an average length of and weighing around ....
. Dimetrodon was also shown as having an egg-laying style similar to the modern crocodile

Crocodile

A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all members of the order Crocodilia: i.e....
, though no evidence regarding Dimetrodon reproduction has ever actually been found.

Dimetrodon was one of several prehistoric animals seen in the Rite of Spring
The Rite of Spring

The Rite of Spring, commonly referred to by its original French language title, Le Sacre du Printemps is a ballet with music by the Russian composer Igor Stravinsky, original choreography by Vaslav Nijinsky, and original set design and costumes by archaeologist and painter Nicholas Roerich, all under impresario Serge Diaghilev....
segment of Disney's Fantasia
Fantasia (film)

Fantasia is a 1940 in film List of animated feature-length films produced by Walt Disney, and is the third film in the List of Disney theatrical animated features#official canon....
, where it is shown as an intermediate predator, preying upon Nothosaurus
Nothosaurus

Nothosaurus is an extinct genus of sauropterygian reptile from the Triassic period, approximately 240-210 million years ago, with fossils being distributed from North Africa and Europe to China....
but fleeing from a Tyrannosaurus
Tyrannosaurus

Tyrannosaurus is a genus of theropod dinosaur. The famous species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture around the world....
.

Dimetrodon

Description

Sail

Relationship with modern mammals

In popular culture

Gallery of species

See also