Tag Archives: crab

Scyra acutifrons: Sharp-nosed crab– The Race Rocks Taxonomy

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This individual is well camouflaged and you can see the other associated organisms around it. The red circle is a serpulid worm

Geographic range is Alaska to Mexico

Size: up to 45mm (1.7 inches)

Domain Eukarya
Kingdom Animalia
Phylum Arthopoda
Subphylum Crustacea
Class Malacostrata
Superorder Eucarida
Order Decapoda
Family Epialtidae
Genus Scyra
Species acutifrons
Common Name:Sharp-nosed crab 

This is a reasonably common crab especially around the dock and higher subtidal areas. The adult males have large claws that they seem to keep folded in. The nose is flat and pointed. The crab shells are often covered with barnacles and other growth as can be seen in this picture. This species puts relatively little effort into decorating, occasionaly placing a small pieces of material on its rostrum but generally appearing to just let organisms colonize its roughened carapace. It feeds primarily on detritus and sessile invertebrates, and sometimes it associates with sea anemones. Females with eggs have been found all months but April to May and September to October. Number of eggs carried ranges fom 2,700 to 16,300.

References:

http://www3.bc.sympatico.ca/kerryw/creature/sharp.htm

Jensen G.C. 1995. Pacific Coast Crabs and Shrimps. Sea Challengers, Monterey, CA. p. 21.

Kozloff, E.N. 1983. Seashore Life of the Northern Pacific Coast. University of Washington Press. Washington. 370 pages.

Morris, R., P. Abbott, and E. Haderlie. 1980. Intertidal Invertebrates of California. Stanford University Press, California. 690 pages.

 

Other Members of the Phylum Arthropoda at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

Sumak Serrano (PC year 28)

Phyllolithodes papillosus: Heart Crab –The Race Rocks Taxonomy

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The Heart Crab – Phyllolithodes papillosusGeneral Description:

This very distinct crab is most commonly identified by the heart shaped markings on its back, hence his common name, the Heart Crab. This triangular carapace measures from 50X60mm (female) to 90X90mm (male), and is coloured a muddy greenish brown with dark red ridges. The claws, legs and carapace are covered in prickly spines, which helps to camouflage and as a defense mechanism. The Heart Crab has three pairs of walking legs coloured dark brown and a pair of chelipeds that are dark brown with turquoise bumps. Another distinction that is evident on the Heart Crab is the two blunt horns above his eyes and a large spine between them.
Domain Eukarya
Kingdom Animal
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Family Lithodidae
Genus Phyllolithodes
Species papillosus
Common Name: Heart Crab
Habitat and Range:

The Heart Crab is rarely sighted in the open nor do they inhabit the intertidal zone, instead they prefer to live subtidally in a rocky habitat, hiding in crevices with moderate exposure and strong currents. They range along the Pacific coast of North America from Alaska to California inhabiting areas as deep as 183m.

Predators and Prey:

The main predator of the Heart Crab is the octopus, and the main prey of heart crabs are sponges and sea urchins, however they are observed eating other things in captivity.

Reproduction:

All mature female Heart Crabs undergo an obligate molt occuring in the spring, from March through May. At this time of molting female are held by the chelipeds of a male. After the molting is finished and the female’s exoskeleton has hardened, the couple copulate. During this a ribbon containing spermatophores is attached around the female. The fertilization occurs within hours, after this the male separates from the female. The female then incubates her eggs for almost twelve months. Eggs are layed in the late summer, August through September. Newly laid eggs are bright yellow, orange or dark red coloured which eventually dull to a muddy brown prior to hatching.

Biotic Association:

An interesting behavior observed of the Heart Crab is the form of symbiosis,commensalism, the association between two organisms when one organism benefits and the other is neither harmed nor benefited. After molting, the Heart Crab takes shelter under the tentacle canopy of the snakelock anemone, as he is not harmed by this and the crab is protected,
References:Accessed Jan.25, 2001

http://oceanlink.island.net/oinfo/biodiversity/heartcrab.html

http://www3.bc.sypatico.ca/kerryw/creature/heart.htm

http://www.afsc.noaa.gov/kodiak/photo/triangle.htm

 

Other Members of the Phylum Arthropoda at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

Cait Caines–year 28(PC)