Glebocarcinus oregonensis: Pygmy Rock Crab–The Race Rocks Taxonomy

rm281010crabl

Glebocarcinus  oregonensis Pygmy rock crab-photo by Ryan Murphy

 

Empty giant acorn shells are often the home for this small crab at Race Rocks. It was formerly called Cancer oregonensis

Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Brachyura
Family: Cancridae
Genus: Glebocarcinus
Species: G. oregonensis
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.  G. Fletcher

 

Pagurus beringanus: Bering hermit crab–The Race Rocks Taxonomy

rm241010herml

Pagurus beringanus, The Bering hermit crab. photo by Ryan Murphy, 2010

This is a tentative identification of Pagurus Beringanus – the Bering Hermit Crab is an animal that is found from the Bering Sea to Monterrey, California. They are also found at Race Rocks. Commonly found at depths from intertidal to 365 meters.

This Pagurus is identifiable by their pale grey-blue shells (carapaces) mottled with grey, red and yellow spots. Legs are also pale blue with red bands at the joints. Claws are reddish and densely covered with spines. Bering Hermit Crabs all have characteristic green, irridescent eyes
Habitat – rocky, intertidal areas with cold water.
Behavior – Adults are inactive during the day. Starting late afternoon and carrying on through the night they become active and feed. This is because the retinal pigments in the eyes with position of the day and the night, only in response to the ambient light in the water.
Bering Hermit Crabs are scavengers, which makes the fact that they taste good puzzling. They eat dead plant materials and dead animal matter.
They themselves are prey to several types of fish, including pine perch, the California sheephead and the spotted kelpfish.
Females have been recorded with eggs mainly in April and May but some as early as February. During courtship, the male carries the female around for a day or more, knocking their shells together. The actual mating lasts less than a second, and both animals come almost completely out of their shells to perform the act.
References:
Intertidal Invertebrates of California. Morris, Abbot, Haderlie, 1980
Pacific Coast Crabs. Gregory C Jensen, 1995
Between Pacific Tides. Ricketts, Calvin, Hedgpeth, 1997

Classification:
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Superfamily: Paguridea
Family: Paguridea
Genus: Pagurus
Species: beringanus
Common Name: Bering Hermit Crab

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.
Carmen Braden (PC yr 29) 2002

 

Lepeophtheirus.sp: Sea Louse–The Race Rocks Taxonomy

parasite

Close up of parasitic sea lice on the head of a ling cod. Photos  by Dr. Armand Svoboda

lepeophtherius sp.

Lepeophtheirus.sp: Sea Louse-on the head of a ling cod — photo by Dr. A. Svoboda

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Suphylum Crustacea
Class Maxillopoda
Order Siphonostomatoida
Family Caliguidae
Genus Lepeophtheirus
Species sp.
Common Name: Parasitic copepod

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. Garry Fletcher

 

Telmessus cheiragonus–The Race Rocks Taxonomy

helmet crab

Telmessus cheiragonus, photo by G. Fletcher

 

helmetventral

Telmessus cheiragonus, the helmet crab, ventral inage by G. Fletcher

Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Family: Cheiragonidae
Genus Telmessus
Species cheiragonus
Common Name: Helmet crab

helmet3

Telmessus cheiragonus, Helmet crab photo by G. Fletcher

This crab shows up frequently when we are diving at Race Rocks

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.  G. Fletcher

 

Hemigrapsus oregonensis: Shore crab-The Race Rocks Taxonomy

hemigrap?

Hemigrapasus oregonensis photo by Anne Stewart. In log

Physical description:
Hemigrapsus oregonensis (Beige shore crab) has dull olive-coloured hairs on its legs and it is lack of reddish spots on the claws. The legs have abundant setae and the chelipeds have no purple spots, but have yellow or white on the tips. There are 3 teeth on the anterolateral margin of the carapace. It has a carapace width ranging up to 34.7mm for males and 29.1 mm for females. It is usually dark or grayish green in color, but white or mottled patterns are common, especially among juveniles. It also has a four-lobed anterior margin.

Global Distribution:
Hemigrapsus oregonensis occurs from the high to low intertidal zones of bays and estuaries from Resurrection Bay (Alaska) to Bahia de Todos Santos (Baja California).

Habitat:
It is most commonly found under rocks, throughout the intertidal zone. They live on open mud flats and in mats of the green alga Enteromorpha and beds of the eelgrass Zostera. It can also be found in rocky habitats within estuaries, gravel shores and in estuaries where it constructs burrows in mud banks. Generally, it prefers more protected and slow water current area. Hemigrapsus nudus always stay together with Hemigrapsus oregonensis.

Feeding:
Hemigrapsus oregonensis feeds mainly at night. The diet of it consists primarily of diatoms, sea lettuce and green algae, but occasionally includes meat if it is available. It scraps up diatoms and crop algae. It also preys on a wide range of small invertebrates, scavenges if it is possible. It can filter-feed by using its third maxillipeds.

Predators:
Predators include shorebirds and Carcinus maenas. A type of red ribbon worm is also a predator of the eggs of Hemigrapsus oregonensis. .

Reproduction:
In northern waters ovigerous females are seen from February to September. The number of eggs carried by the female is ranged from 100 to 11,000 (with an average number of 4,500). Hatching occurs from May to July with one pre-zoeal stage occurring inside the egg. Planktonic larvae develop through five post-hatching zoeal stages. The larvae typically spend five weeks in the plankton.
In August some females produce a second brood which hatches in September. Time from egg deposition to adult recruitment is variable and depends on several factors: the quantity and quality of food available, water temperature and salinity. Altogether it takes about 8-13 weeks for a brood to hatch, metamorphose and be recruiting into the adult population.

oregonshorecrab

Oregon Shore crab G.Fletcher photo

Scientific Classification
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Family Grapsidae
Genus Hemigrapsus
Species oregonensis
Common Name: shore crab

Sea otters, currently abundant in Elkhorn Slough and only historically abundant in more northern bays, are limiting Hemigrapsus oregonensis populations. One paradigm in the study of exotic species is that healthy ecosystems, with a full complement of native species, are more difficult to invade than modified systems. In this case, sea otters may be eating the introduced species, as evidenced by Hemigrapsus oregonensis parts in recent scat analyses. While the current West Coast range for Hemigrapsus oregonensis is Morro Bay, California to Barkley Sound, British Columbia, studies at Elkhorn Slough may change how scientists and resource managers predict the impacts of introduced marine species.”

References:(accessed 2005)
http://oregonstate.edu/~yamadas/crab/ch9.htm
http://people.wwc.edu/staff/cowlda/KeyToSpecies/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/Eucarida/Decapoda/
Brachyura/Family_Grapsidae/Hemigrapsus_oregonensis.html
http://oceanlink.island.net/oinfo/intertidal/arthropod.html
http://www.nwmarinelife.com/htmlswimmers/h_oregonensis.html
http://www.ci.edmonds.wa.us/Discovery_Programs%20Website/Crustaceans.html
http://oregonstate.edu/~yamadas/crab/ch5.htm

Marine Invertebrates of the Pacific Northwest by Eugene N. Kozloff

by Student  Karyn Wong, PC yr 32 -2005
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.

Semibalanus carriosus: Thatched barnacle–The Race Rocks Taxonomy

Screen Shot 2015-01-08 at 6.51.40 PM

Student pointing to thatched barnacles . Note goose- neck barnacles on the rock above.

Student pointing to thatched barnacles . Note goose- neck barnacles on the rock above.

Thatched barnacles are at a relatively low level in the intertidal zone as can be sen in this photo of their habitat.

 

 

 

 

Domain Eukarya
Kingdom
Phylum
Class
Order
Family

Genus Semibalanus
Species carriosus
Common Name: Thatched barnacle

0407whiteblackbarnaclel copy
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.

 

Pagurus hirsuitiusculus: hairy hermit crab–The Race Rocks Taxonomy

This video shows the two species, the Hairy hermit crab Pagurus hirsuitiusculus and the sponge Suberites in a commensal biotic association.

hairy-pagurus

Hairy Hermit Crab: photo by Ryan Murphy

bandedantennae

A distinguishing feature of the hairy hermit crab is te banded antennae shown in this image from the video

The specimens studied were collected at  Race Rocks in November of 2002. They were unique specimens because of their choice of home. Usually hermit crabs use the shells of snails that have died then discard them as they grow larger in place of a bigger shell. However, these Hairy Hermit Crabs had decided to become the hermit crabs of Hermit Crab Sponges.

Hermit Crab Sponges, Suberites.spp are sponges that attach themselves to a mobile animal who has a solid exoskeleton, usually a snail or crab. In the hermit crab’s case, the sponge begins to grow on their adopted home by first thinly encrusting the shells. As the sponge grows, it begins to cover the shell and can surround it completely, sometimes making locomotion difficult for the crab. Once the sponge has buried the shell inside itself, the hermit crab leaves its shell to occupy a chamber in the sponge it had hollowed out.

CLASSIFICATION:
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Superfamily: Paguridea
Family: Paguridea
Genus: Pagurus
Species: hirsuitiusculus
Pagurus hirsuitiusculus
Common Name: Hairy Hermit Crab

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.