Sturgeon is the common name for the 28 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae). The family is grouped into four genera: Acipenser, Huso, Scaphirhynchus, and Pseudoscaphirhynchus. Two species may be extinct in the wild, and one may be entirely extinct. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. A Maastrichtian-age fossil found in Morocco shows that they also once lived in Africa.
Yanosteus longidorsalis, a member of the extinct acipenseriform family Peipiaosteidae from the Early Cretaceous (125–120 Mya) Yixian Formation in Liaoning, China
A young lake sturgeon (Acipenser fulvescens)
Great sturgeon or beluga (Huso huso) feeding on another fish
Sturgeon depicted on an ancient Greek Tetrachalkon (bronze coin) from Panticapaeum on the Crimean peninsula (Black Sea), 310–304 B.C.
Acipenseriformes is an order of basal ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct families Chondrosteidae and Peipiaosteidae. They are the second earliest diverging group of living ray-finned fish after the bichirs. Despite being early diverging, they are highly derived, having only weakly ossified skeletons that are mostly made of cartilage, and in modern representatives highly modified skulls.
Fossil of the †chondrosteid †Strongylosteus hindenburgi, Tübingen
Fossil of the †peipiaosteid †Yanosteus longidorsalis, MHNT
The living polyodontid Polyodon spathula (American paddlefish)
The living acipenserid Acipenser ruthenus (sterlet)