Taxonomy and evolution

first described the alligator gar in 1803. The original name was Lepisosteus spatula, but was later changed by E.O. Wiley in 1976 to Atractosteus spatula to recognize two distinct taxa of gars. Synonyms of Atractosteus spatula include: Lesisosteus [sic] ferox (Rafinesque 1820), and Lepisosteus spatula (Lacepede 1803). Fossils from the order Lepisosteiformes have been collected in Europe from the Cretaceous to Oligocene periods; in Africa and India from the Cretaceous; and in North America from the Cretaceous to recent times. The Lepisosteidae are the only extant family of gars with seven species, all located in North and Central America.[8] The fossil record traces the existence of gars such as the Alligator gar back over 100 million years ago to the Early Cretaceous period. Despite being a highly evolved species, alligator gar are often referred to as "primitive fishes" or "living fossils", because they have retained a few morphological characteristics of their earliest ancestors, with seemingly few to no apparent changes, such as: a spiral valve intestine, which is also common to the digestive system of sharks; an abbreviate heterocercal tail; and a swim bladder lung for breathing in both air and water.

Description

Alligator gar are the largest species in the gar family, and among the largest freshwater fishes found in North America. Mature alligator gar commonly measure 6 ft (1.8 m) in length, and weigh over 100 lb (45 kg). However, anecdotal reports suggest they can grow up to 10 ft (3 m) in length, and weigh as much as 350 lb (159 kg).