Arthropoda · arthropods

Antarctic krill

Euphausia superba

Euphausiidae · krillIUCN: Least Concern
Antarctic krill
Photo: Uwe Kils · CC BY-SA 3.0 · Wikimedia Commons · resized

A swarming crustacean at the base of the Southern Ocean food web.

Fun factIts total biomass is estimated at hundreds of millions of tonnes, among the largest of any animal species.

Waters
Southern Ocean
Depth zone
Open-ocean surface waters
Diet
Phytoplankton & ice algae
Size
Up to 6 cm

Classification

Arthropoda › Malacostraca › Euphausiacea › Euphausiidae

  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 Protostomia protostomes
    • In the embryo, the first opening usually becomes the mouth
    • Main nerve cord runs along the belly (ventral)
    • Includes mollusks, worms, and arthropods
  4. Clade Ecdysozoa molting animals
    • Grow by shedding their outer layer (molting, ecdysis)
    • No cilia used for movement
    • Includes arthropods and nematode worms
  5. Phylum Arthropoda arthropods
    • Hard outer skeleton made of chitin (exoskeleton)
    • Jointed legs and a segmented body
    • The largest animal phylum by species count
  6. Subphylum Crustacea crustaceans
    • Two pairs of antennae
    • Branched (biramous) legs in many species
    • Most breathe with gills
  7. Class Malacostraca crabs, shrimp & kin
    • Body of a head, 8-segment thorax, and 6-segment abdomen
    • Includes crabs, shrimp, lobsters, krill, and isopods
  8. Order Euphausiacea krill
    • Krill: small, shrimp-like crustaceans
    • Glowing light organs (photophores)
    • Feathery gills are exposed below the carapace
  9. Family Euphausiidae krill
    • Form huge swarms that feed whales, fish, and seabirds
  10. Genus Euphausia
    • Species in the same genus are very close relatives and often look alike.
  11. Species Euphausia superba Antarctic krill

Closest relatives in the guide