Arthropoda · arthropods

Northern krill

Meganyctiphanes norvegica

Euphausiidae · krillIUCN: Not evaluated
Northern krill
Photo: Saperaud · CC BY-SA 3.0 · Wikimedia Commons · resized

A North Atlantic krill eaten by fin whales, herring, and seabirds.

Fun factIt migrates hundreds of meters up and down the water column every day.

Waters
Northeast US, Northwest Atlantic, Northeast Atlantic
Depth zone
Open-ocean surface waters, Twilight zone, 200–1,000 m
Diet
Copepods & phytoplankton
Size
Up to 4.5 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 Meganyctiphanes
    • Species in the same genus are very close relatives and often look alike.
  11. Species Meganyctiphanes norvegica Northern krill

Closest relatives in the guide