Arthropoda · arthropods

Dungeness crab

Metacarcinus magister

Cancridae · rock crabsIUCN: Not evaluated
Dungeness crab
Photo: Dan Boone · Public domain · Wikimedia Commons · resized

The most valuable crab fishery on the US West Coast.

Fun factFishing seasons are often delayed by domoic acid from harmful algal blooms.

Waters
North Pacific, Eastern Pacific
Depth zone
Coastal shallows & estuaries, Continental shelf
Diet
Clams, fish & small crustaceans
Size
Carapace up to 25 cm

Classification

Arthropoda › Malacostraca › Decapoda › Cancridae

  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 Decapoda ten-legged crustaceans
    • Ten walking legs, the first pair often with claws
    • Shell covers head and thorax together (carapace)
  9. Suborder Pleocyemata egg-brooding decapods
    • Females carry their eggs under the abdomen until they hatch
    • Includes true crabs, lobsters, and most shrimp
  10. Infraorder Brachyura true crabs
    • True crabs: abdomen tucked tightly under a broad carapace
    • Walk sideways on four pairs of legs
  11. Family Cancridae rock crabs
    • Rock crabs: broad, oval carapace
    • Many are commercial species
  12. Genus Metacarcinus
    • Species in the same genus are very close relatives and often look alike.
  13. Species Metacarcinus magister Dungeness crab

Closest relatives in the guide