Chordata · chordates

Beluga sturgeon

Huso huso

Acipenseridae · sturgeonsIUCN: Critically Endangered
Beluga sturgeon
Photo: Максим Яковлєв · CC BY-SA 4.0 · Wikimedia Commons · resized

The largest bony fish of the Caspian and Black seas, and the source of beluga caviar.

Fun factHistoric specimens weighed more than 1,500 kg.

Waters
Mediterranean & Black Sea
Depth zone
Coastal shallows & estuaries, Continental shelf
Diet
Fish
Size
Up to 7 m

Classification

Chordata › Actinopterygii › Acipenseridae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Deuterostomia deuterostomes
    • In the embryo, the first opening becomes the anus and the mouth forms second
    • Includes echinoderms and chordates
  4. Phylum Chordata chordates
    • At some stage of life: a stiffening rod along the back (notochord)
    • A hollow nerve cord along the back (dorsal)
    • Slits in the throat (pharyngeal slits) and a tail past the anus
  5. Subphylum Vertebrata vertebrates
    • A skull (cranium) protecting a brain
    • Backbone or similar support around the nerve cord
    • Includes fishes, amphibians, reptiles, birds, and mammals
  6. Infraphylum Gnathostomata jawed vertebrates
    • Jawed vertebrates: jaws formed from gill arches
    • Paired fins or limbs
    • Includes all fishes except hagfish and lampreys, plus all tetrapods
  7. Superclass Osteichthyes bony vertebrates
    • Bony vertebrates: skeleton made largely of bone
    • Most have a lung or swim bladder
    • Includes ray-finned and lobe-finned fishes and all tetrapods
  8. Class Actinopterygii ray-finned fishes
    • Ray-finned fishes: fins are webs of skin held up by thin bony rays
    • Usually a gas-filled swim bladder for buoyancy
    • About half of all vertebrate species
  9. Subclass Chondrostei sturgeons & paddlefishes
    • Sturgeons and paddlefishes: mostly cartilage skeleton despite being bony fishes
    • Shark-like tail with a longer upper lobe
  10. Family Acipenseridae sturgeons
    • Sturgeons: rows of bony plates (scutes) along the body
    • Barbels in front of a toothless, tube-like mouth
  11. Genus Huso
    • Species in the same genus are very close relatives and often look alike.
  12. Species Huso huso Beluga sturgeon

Closest relatives in the guide