Caucasian sturgeon

The Caucasian sturgeon or Colchis sturgeon (Huso colchicus) is a highly endangered species of sturgeon native to the eastern Europe and western Asia, where it is found in the southeastern Black Sea & associated river basins, as well as the lower Danube River. It is named after the historic region of Colchis.

It was long considered a subspecies of the Russian sturgeon (H. gueldenstaedtii) or the Persian sturgeon (H. persicus), which themselves were previously placed in the genus Acipenser. However, recent phylogenetic studies have reclassified both into Huso, and have affirmed the distinctiveness of the Caucasian sturgeon from both of these species. Phylogenetic evidence indicates that the Caucasian sturgeon is most closely related to the Adriatic sturgeon (H. naccarii). It cannot be properly differentiated from the Russian sturgeon by morphology alone, and very little has been studied about its phylogenetics.