Dimetrodon

Dimetrodon is an extinct genus of sail-backed synapsids that lived in the Early Permian, roughly 295–272 million years ago. It was a close relative of mammals, not a dinosaur.

Synapsid: A vertebrate lineage distinguished by one opening behind each eye socket, including mammals and their extinct relatives. Dimetrodon belongs to this lineage, rather than to the reptile lineage that includes dinosaurs.
Neural spine: A bony projection extending upward from a vertebra. Dimetrodon's elongated neural spines supported the structure of its back sail.
Dimetrodon grandis: A large species of Dimetrodon known from Early Permian deposits in North America. Its imposing size makes it one of the genus's most recognizable species.
Dinosaur: A member of Dinosauria, the diverse reptile lineage that arose during the Triassic Period. Dimetrodon lived before dinosaurs and belonged to a different vertebrate lineage.
Early Permian: The first epoch of the Permian Period, spanning about 299 to 273 million years ago. Dimetrodon lived during this epoch, long before dinosaurs appeared.
Thermoregulation: The regulation of an organism's body temperature through physiological or behavioral processes. The sail's possible role in heat exchange has been debated, but its function remains uncertain.
Dimetrodon limbatus: A species of Dimetrodon named from fossils found in Texas. Its fossils helped establish the genus from the extensive Texas record.
Edaphosaurus: An extinct herbivorous synapsid with a tall back sail, living in the Early Permian. It shared Dimetrodon's broad era and silhouette but had a different diet and body form.
Sphenacodontidae: An extinct family of predatory synapsids that includes Dimetrodon and its close relatives. This is the family that contains Dimetrodon.
Heterodont dentition: A pattern of teeth with different shapes and functions in the same jaw. Dimetrodon's differentiated teeth suggest it could grip and slice prey.

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