Voracious freshwater fish (Amia calva) that is the only living representative of the family Amiidae, which dates back to the Jurassic period (206-144 million years ago). It is found in sluggish North American waters from the Great Lakes southward to the Gulf of Mexico. Mottled green and brown, it has a long dorsal fin and strong conical teeth. The female, which is larger than the male, reaches a length of 30 in. (75 cm). The bowfin spawns in spring, when the male constructs a crude nest and guards both the fertilized eggs and the newly hatched young. It is sometimes called a dogfish