The bowfin, Amia calva, is a primitive species of bony fish related to the alligator gar in the taxon Holostei. The bowfin is the last surviving member of the order Amiiformes (which includes three 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. The bowfin is able to breathe air, using its swim bladder, which is connected to its gastrointestinal tract and allows it to regulate buoyancy in the water, as a primitive lung. The fish can be seen coming to the surface and gulping air. This limits it to a specific depth range in which the surface is accessible. They tend to use shoreline habitats that are not accessible to other predatory fish.
Description and biology
The most distinctive characteristic of the bowfin is its very long dorsal fin consisting of 145 to 250 rays, and running from the middle of the back to the base of the tail. The caudal fin is a single lobe, though heterocercal. They can grow up to 109 cm (43 in) in length, and weigh 9.75 kg (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.
The bowfin is an indiscriminate predator that readily preys on a broad variety of arthropod and vertebrate prey, from insects and crawfish to other fish and frogs.
The male bowfin exhibits extensive parental care. The male clears an area in the mud for the female to lay eggs in, and then fertilizes them. He hovers nearby and aggressively protects the eggs and the fry after they emerge.
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