Arthropoda · arthropods

Long-clawed hermit crab

Pagurus longicarpus

Paguridae · right-handed hermit crabsIUCN: Not evaluated
Long-clawed hermit crab
Photo: Eric A. Lazo-Wasem · CC0 · Wikimedia Commons · resized

A small hermit crab that lives in periwinkle and moon snail shells.

Fun factHermit crabs line up by size to swap shells in vacancy chains.

Waters
Northeast US, Northwest Atlantic
Depth zone
Intertidal shore, Coastal shallows & estuaries
Diet
Detritus & small invertebrates
Size
Body about 1.5 cm

Classification

Arthropoda › Malacostraca › Decapoda › Paguridae

  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 Anomura hermit & king crabs
    • Last pair of walking legs is small and often hidden
    • Includes hermit crabs, king crabs, and mole crabs
  11. Family Paguridae right-handed hermit crabs
    • Right-handed hermit crabs: soft, curled abdomen hidden in a borrowed snail shell
  12. Genus Pagurus
    • Species in the same genus are very close relatives and often look alike.
  13. Species Pagurus longicarpus Long-clawed hermit crab

Closest relatives in the guide