Description: This majid
crab has a flattened
that is longer than wide but less than half the carapace
length, and is widest near the middle (photo).
is triangular, has a projection or lump near the two posterolateral
corners, but has no sharp projection or shelf on the anterolateral
margin. The chelipeds
of males are usually longer than the walking legs, slender, and tipped
with orange. When at rest the crab often sits with its chelae
near its mouth and its very long "elbows" projecting out in front.
is brown or tan but may be overgrown with sponges and bryozoans.
width to 4.5 cm.
Scyra acutifrons Dana, 1851
Common name(s): Sharp-nosed crab
Brachyura (true crabs)
|A male Scyra acutifrons from Swirl Rocks, WA. Carapace
width about 4.5 cm.
|(Photo by: Dave Cowles, July 2000)
How to Distinguish from Similar Species: Oregonia
bifurca and Hyas lyratus have
a lyre-shaped body and a toothed expansion of the carapace
on both sides of the anterior half, plus the rostrum
is widest at the base. Pugettia
gracilis, Pugettia producta,
and Pugettia richii have a sharp projection to the side near the
middle of the carapace.
Geographical Range: Kodiak, Alaska to Punta
San Carlos, Mexico. Uncommon south of Monterey Bay, CA
Depth Range: Mostly subtidal, to 220 m
Habitat: Rocky areas, especially around
boulders densely covered with invertebrates. Sometimes found on pilings.
Feeds on detritus
and sessile invertebrates. Predators include rockfish (Sebastes
atrovirens, S. chrysomelas and S. caurinus), kelp greenling
decagrammus, and sculpins. Seems to be often found around
sea anemones. May decorate slightly by putting a few pieces of algae
on its rostrum. Other algae and bryozoans seem to overgrow the carapace
naturally. This crab often sits with the anterior end pointed down.
Females may carry eggs nearly any time of year. May reproduce several
times a year. This species has a terminal molt so full-grown adults
will no longer grow (and the carapace
can become overgrown with organisms)(photo)
and Fairbanks, 1966
and Carlton, 1975
et al., 1980
General Notes and Observations: Locations, abundances,
This individual is hiding under a subtidal rock near Rosario.
Notice the characteristic pose with the elbows forward/out and the chelae
held near the mouth. Underwater photo by Jim Nestler, July 2005
A view of another individual, captured between 100-120 m depth in the
San Juan Channel. Photo by Dave Cowles, August 2015.
|The underside of males and females looks somewhat different:
|Male underside: Abdomen
tapers toward a point at the end. The chelipeds
have numerous blunt knobs on the ischium,
in marginal rows and scattered. Photo by Dave Cowles, Aug 2017
||Female underside: The abdomen
is more squared off on the end, and the blunt knobs on the chelipeds
are smaller as well as less numerous and prominent. Photo by Dave Cowles,
This individual is heavily encrusted with barnacles
suggesting that it has been quite some time since it has molted. It has
likely reached terminal molt. Photo by Dave Cowles, August 2017
Authors and Editors of Page:
Dave Cowles (2005): Created original page