Arthropoda · arthropods

Asian shore crab

Hemigrapsus sanguineus

Varunidae · shore crabsIUCN: Not evaluated
Asian shore crab
Photo: Chuck Homler d/b/a Focus On Wildlife · CC BY-SA 4.0 · Wikimedia Commons · resized

A banded-legged invasive crab now dominant under rocks from Maine to North Carolina.

Fun factIt was first found in New Jersey in 1988, probably carried in ships' ballast water.

Waters
Northeast US, Northwest Atlantic, Western Pacific
Depth zone
Intertidal shore
Diet
Algae, mussels & barnacles
Size
Carapace up to 4 cm

Classification

Arthropoda › Malacostraca › Decapoda › Varunidae

  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 Varunidae shore crabs
    • Shore crabs of rocky and muddy coasts
    • Includes the invasive Asian shore crab
  12. Genus Hemigrapsus
    • Species in the same genus are very close relatives and often look alike.
  13. Species Hemigrapsus sanguineus Asian shore crab

Closest relatives in the guide