Polybiidae

The Polybiidae are a family of spider crabs found in the marine environment. They are characterized by their broad, flattened carapace and long, spiny legs. They are found in a variety of habitats, including shallow waters, rocky reefs, and seagrass beds. The family Polybiidae is classified under the infraorder Brachyura, within the order Decapoda, belonging to the phylum Arthropoda.

Velvet Swimming Crab – Necora puber

Common Names

Members of the Polybiidae family are commonly referred to as spider crabs due to their long, spindly legs. Specific species may have additional common names, such as the Japanese spider crab (Macrocheira kaempferi) and the giant spider crab (Lithodes antarcticus).

Characteristics

Polybiidae crabs share several distinct characteristics that set them apart from other crab families. These include:

  • Broad, flattened carapace: This characteristic gives them a distinctive, somewhat domed appearance.
  • Long, spiny legs: Their legs are remarkably long and often covered in spines. These spines serve both as protection and as a way to camouflage themselves.
  • Small, reduced abdomen: Unlike many other crabs, their abdomens are tucked under their bodies and are relatively small.
  • Variable sizes: Polybiidae crabs range in size from small, relatively inconspicuous species to the enormous Japanese spider crab, which can have a leg span of over 12 feet.

Environments

Polybiidae crabs are found in a variety of marine environments around the world, including:

  • Shallow waters: Many species inhabit shallow coastal waters, particularly rocky areas and seagrass beds.
  • Rocky reefs: They are often found clinging to rocks or hiding in crevices.
  • Seagrass beds: Some species use seagrass as a source of food and shelter.
  • Deep waters: Certain species, such as the giant spider crab, are found in deep ocean environments.

References

For more detailed information on Polybiidae crabs, consult these reliable resources: