Polyodon spathula

American paddlefish
American paddlefish (centre of image)
Conservation status
Vulnerable (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acipenseriformes
Family:	Polyodontidae
Genus:	Polyodon Lacépède, 1797
Species:	P. spathula
Binomial name
Polyodon spathula (Walbaum in Artedi 1792)
Synonyms
Genus Spatularia Shaw 1804 non Haworth 1821 non van Deventer 1904 non Mehely 1935 Platirostra LeSueur 1818 Megarhinus Rafinesque 1820 non Schoenherr 1833 nomen nudum non Robineau-Desvoidy 1827 Proceros Rafinesque 1820 non Quatrefages 1845 Species Squalus spathulus Walbaum 1792 Megarhinus paradoxus Rafinesque 1820 Platirostra edentula Lesueur 1818 Polyodon feuille Lacépède 1797 Polyodon folius Bloch & Schneider 1801 Proceros maculatus Rafinesque 1820 Spatularia reticulata Shaw 1804 Proceros vittatus Rafinesque 1820 Accipenser lagenarius (sic) Rafinesque 1820  ?Polyodon pristis Rafinesque 1818

The American paddlefish (Polyodon spathula) is a species of basal ray-finned fish closely related to sturgeons in the order Acipenseriformes. Fossil records of paddlefish date back over 300 million years, nearly 50 million years before dinosaurs first appeared. American paddlefish are smooth-skinned freshwater fish commonly called paddlefish, but are also referred to as Mississippi paddlefish, spoon-billed cats, or spoonbills. They are one of only two extant species in the paddlefish family, Polyodontidae. The other is the critically endangered Chinese paddlefish (Psephurus gladius) endemic to the Yangtze River basin in China. American paddlefish are often referred to as primitive fish, or relict species because they retain some morphological characteristics of their early ancestors, including a skeleton that is almost entirely cartilaginous, a paddle-shaped rostrum (snout) that extends nearly one-third their body length, and a heterocercal tail or caudal fin, much like that of sharks. American paddlefish are a highly derived fish because they have evolved with adaptations such as filter feeding. Their rostrum and cranium are covered with tens of thousands of sensory receptors for locating swarms of zooplankton, which is their primary food source.

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Wikipedia