High Quality Content by WIKIPEDIA articles! The pallid sturgeon (Scaphirhynchus albus) is an endangered species of ray-finned fish, endemic to the waters of the Missouri and lower Mississippi River basins of the United States. Named for its pale coloration, the pallid sturgeon is closely related to the relatively common shovelnose sturgeon (Scaphirhyncus platorhynchus), but is much larger, averaging between 30 and 60 inches (76 and 150 cm) in length and 85 pounds (39 kg) in weight at maturity. The pallid sturgeon takes 15 years to mature and spawns infrequently, but can live for up to a century. A member of the Acipenseridae (sturgeon) family of fish that originated during the Cretaceous period 70 million years ago, the pallid sturgeon has remained essentially unchanged. The species is considered to be a relict of the dinosaur era, and has been called "one of the ugliest fish in North America".