The Bowfin, Amia calva, is the last surviving member of the order Amiiformes (which includes 3 additional, now-extinct families dating from the Jurassic, to the Eocene), and of the family Amiidae (which contains numerous species in about four subfamilies, only one of which, Amiinae, is extant). The Bowfin is a freshwater piscivore, preying on fish and larger aquatic invertebrates by ambush or stalking. Native to southeastern Canada and eastern United States, they prefer shallow, weedy waters of lakes or protected back waters of rivers. Bowfin are able to breathe air, using their swim bladder, which is connected to their gastrointestinal tract and allows them to regulate their buoyancy in the water, as a primitive lung. The fish can be seen coming to the surface and gulping air. This limits them to a specific depth range in which the surface is accessible. They tend to utilize shoreline habitats that are not accessible to other predatory fish. The most distinctive characteristic of the bowfin is its very long dorsal fin consisting of 145 to 250 rays, and running from mid-back to the base of the tail. The caudal fin is a single lobe, though heterocercal. They can grow up to 109 centimetres (43 in) in length, and weigh 9.75 kilograms (21.5 lb). Other noticeable features are the black "eye spot" usually found high on the caudal peduncle, and the presence of a gular plate. The gular plate is a bony plate located on the exterior of the lower jaw, between the two sides of the lower jaw bone.
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