Edestus

Edestus is an extinct genus of eugeneodontid holocephalian fish known from the Late Carboniferous (Pennsylvanian) of the United Kingdom, Russia, and the United States. Most remains consist of isolated curved blades or "whorls" that are studded with teeth, that in life were situated within the midline of the upper and lower jaws. Edestus is a Greek name derived from the word edeste (to devour), in reference to the aberrant quality and size of the species' teeth. The largest species, E. heinrichi, has been conservatively estimated to reach greater than 6.7 m (22 ft) in length, around the size of the largest known great white shark, possibly making it the largest marine predator known to have ever existed up to that point. Like its other relatives, such as Helicoprion, and unlike modern sharks, the species of Edestus grew teeth in curved blades or "whorls". In Edestus' case, only a single row of teeth occurred in the midline of each jaw, leading Edestus to sometimes be described as the "scissor tooth shark". The degree of curvature in the teeth brackets, along with size, are distinct in each species.