Sharp-nosed Crab

Scyra acutifrons

Sharp-nosed Crab

Scyra acutifrons

At the Aquarium

Sandy Coast

Appearance

This small crab is named for its flat rostrum that is longer than it is wide and has 2 sharp tips. Its bumpy, triangle-shaped carapace reaches up to 1.8” in width. It has relatively short walking legs but long and slender claws, with males having longer chelipeds than walking legs. The claws are usually red with white teeth.

Habitat

Mostly subtidal in rocky areas

Diet

Detritus and sessile invertebrates

Life History

The sharp-nosed crab has a terminal molt upon reaching adulthood, so it no longer molts or grows. In a single brood a female will have roughly 150 eggs but she can reproduce several times a year.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

These crabs are important because they eat detritus, thus recycling those nutrients back into the system. They also feed many fish predators including a variety of rockfish species, kelp greenlings, and sculpins.
Their rough carapace provides a settling site for a variety of sessile invertebrates including barnacles, sponges, and even small anemones.
Alaska to Mexico
These crabs can be found in the lower intertidal zone so keep an eye out for them while tidepooling.
These crabs are not active decorators but their rough carapace allows organisms such as sponges and bryozoans to grow on it.

Citations & Other Resources

  • Cricket Raspet, Scyra acutifrons, CC BY 4.0
  • Biodiversity of the Central Coast website: https://www.centralcoastbiodiversity.org/sharp-nosed-crab-bull-scyra-acutafrons.html
  • Hines, Anson H. “Allometric constraints and variables of reproductive effort in brachyuran crabs.” Marine Biology 69 (1982): 309-320.
  • Invertebrates of the Salish Sea website: https://inverts.wallawalla.edu/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/Eucarida/Decapoda/Brachyura/Family_Majidae/Scyra_acutifrons.html
  • Our Wild Puget Sound website: https://www.ourwildpugetsound.com/journal/puget-sound-tide-pooling-guide-preview