Dimetrodon ("two measures of teeth") is a synapsid that had a large sail on its back. It lived in the Permian Period and is commonly mistaken for a dinosaur.
Dimetrodon was the apex predator of its time and was one of the largest land animals. There are many species, ranging in length and weight from 90 centimeters and 14 kilograms to 4 meters and 300 kilograms, respectively.
The most obvious feature of Dimetrodon is its sail. It was supported by spines in the vertebrae. There are many theories about what the sail was used for; namely thermoregulation, camouflage or display.
SkullEditDimetrodon has both shearing and canine teeth, hence the meaning of its name. It was one of the first animals to have such a tooth structure. Its teeth have serrations, but they are very fine.
Dimetrodon was described in 1878 by Edward Drinker Cope as Dimetrodon insicivus. There are now about 16 species of Dimetrodon in existence, which are usually distinguished by the shape of their sail.
Dimetrodon was a synapsid, and so was actually more closely related to modern mammals than to other reptiles. The two types of teeth present in the genus were the first steps in the varied teeth present in mammals today.
Dimetrodon's fossils are found in the United States, and the areas in which it was present would have been wetland, swamp, and floodplain habitat in the Permian. The Red Beds of Texas preserve Dimetrodon fossils particularly well.
Dimetrodon was a carnivore, and could chew with its heterodont teeth unlike other reptiles. Evidence inferred from habitat and directly from fossils suggest that Dimetrodon may have preyed primarily on freshwater fish and tetrapods. I like cheese.
Dimetrodon's bones show that it was cold-blooded and needed external heat for its metabolism. As other animals of the period also had large sails on their back, it is usually suggested that they were used to gather needed heat. According to this theory, Dimetrodon turned its sail towards the sun to warm up, and turned its sail away to cool down. Calculations have shown this process would have taken from one and a half to four hours.
In popular cultureEditBecause Dimetrodon has such a distinctive appearance and is often mistaken for a dinosaur, it has appeared in many forms of media, such as the BBC documentary Walking with Monsters.
- ↑ Kenneth D. Angielczyk, Dimetrodon Is Not a Dinosaur: Using Tree Thinking to Understand the Ancient Relatives of Mammals and their Evolution Evolution: Education and Outreach, Volume 2, Number 2, 257-271, DOI: 10.1007/s12052-009-0117-4
- ↑ Romer, A. S., and Price, L. W., Geological Society of America Special Papers No. 28 (1940).
- ↑ Abler, W.L. 2001. A kerf-and-drill model of tyrannosaur tooth serrations. p. 84-89. In: Mesozioc Vertebrate Life. Ed.s Tanke, D. H., Carpenter, K., Skrepnick, M. W. Indiana University Press.
- ↑ AS Romer. (1946) New genera and species of reptiles pelycosaurian. Proceedings of the New England Zoological Club, 37(434):89-96.
- ↑ Bakker RT. (1982) Juvenile-adult habitat shift in Permian fossil reptiles and amphibians. Science, 217(4552):53-55.
- ↑ WD Maxwell. (1992) "Permian and Early Triassic extinction of non-marine tetra pods". Palaeontology, 25(3): 571-583.
- ↑ http://hmnspaleo.blogspot.com/2007/10/xenacanthus-vs-dimetrodon-battle-of.html
- ↑ GA Floridesa, Kalogiroua SA, SA & L Tassoub Wrobelb. (2001) "Natural environment and thermal behavior of Dimetrodon limbatus". Journal of Thermal Biology, 26(1):15-20.
- ↑ "On the dorsal sail of Dimetrodon". S Rodbard. Herpetological Notes, September 1949, Number 3: p. 224.
- ↑ CD Bramwell & OJ Fellgett. (1973) "Thermal Regulation in Sail Lizards". Nature, 242, 203–205.
- ↑ SC Haack (1986) "A thermal model of the sail back pelycosaur". Paleo Biology, 12(4):203-205.