Ossetra genitive case form "осетра" (osetra, 'of sturgeon') of the Russian word "осётр" (osyotr 'sturgeon') from the phrase "икра осетра" (ikra osetra, 'caviar of sturgeon'). At one time, the term "ossetra" simply referred to Russian sturgeon species harvested for this type of caviar. In Russian, there are different names for the species of sturgeon that live in various territories such as "Beluga" ("Huso huso"), Sevruga ("Acipenser stellatus") and Sterlet ("Acipenser ruthenus"). The name Ossetra corresponds to the species "Acipenser gueldenstaedtii", which is much smaller than Beluga sturgeon ("Huso huso"), and has a firmer texture. In the territory of the Russian Federation
Hypothetical types of biochemistry Hypothetical types of biochemistry Hypothetical types of biochemistry are forms of biochemistry speculated to be scientifically viable but not proven to exist at this time. The kinds of living organisms currently known on Earth all use carbon compounds for basic structural and metabolic functions, water as a solvent, and DNA or RNA to define and control their form. If life exists on other planets or moons, it may be chemically similar; it is also possible that there are organisms with quite different chemistries—for instance, involving other classes of carbon compounds, compounds of another element, or another solvent in place of