Ophiacodon is an extinct genus of synapsid belonging to the family Ophiacodontidae that lived from the Late Carboniferous to the Early Permian in North America and Europe. The genus was named along with its type species O. mirus by paleontologist Othniel Charles Marsh in 1878 and currently includes five other species. Although Ophiacodon lacked a sail like that on the more famous Dimetrodon, Ophiacodon was more of the standard morphology for the pelycosaurs. How Ophiacodon lived and hunted is still a matter of debate today with some claiming that it was a semi aquatic carnivore that fed on fish and amphibians. Support for this comes from the small and numerous teeth that would have been great for gripping slippery prey like fish. There is also a notch at the end of the upper jaw, a trait commonly seen in animals that have a piscivorous diet. Others however suggest that the deep skull would have been more of a hindrance and that the legs seem to support and lift the body up as opposed to just sprawling out from the sides, suggesting a primarily terrestrial locomotion. Regardless of its chosen lifestyle, Ophiacodon was one of the more powerful predators of its day, and possibly only had to fear others of its own kind. The same deep skull is suggestive of powerful muscles capable of delivering a strong bite force. The teeth also show developing size variation that would become more pronounced in later pelycosaurs.
