Category Archives: Phylum Arthropoda

Cyamus kessleri: Gray whale lice–The Race Rocks Taxonomy

Posted on by

Whale lice were removed from the skin of the Gray Whale which was prepared for a skeleton at Lester B. Pearson College. They are currently in the display case beside the mounted whale skeleton.
The lice mainly eat algae that settle on the host’s body. They usually feed off the flaking skin of the whale and frequent wounds or open areas. They cause minor skin damage, which does not lead to illness.

The development of the whale louse is closely connected with the life pattern of whales. The distribution of various lice species reflects migratory patterns.

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Superorder:Peracarida
Order: Amphipoda
Infraorder: Corophiida
Parvorder: Caprellidira
Superfamily: Caprelloidea
Family: Cyamidae
Genus Cyamus
Species kessleri
Common Name: Gray Whale Lice

Reference: from https://journeynorth.org/tm/gwhale/Hitchhikers.html

“Whale lice are another type of whale hitchhiker. Unlike barnacles, lice are true parasites. They feed on gray whale skin and damaged tissue. The lice gather around open wounds or scars. See Photo.

Whale lice may spread from mother whales to their calves during birth, nursing, or other bodily contact. Up to 1000 of these parasites have been found on a single gray whale.

Luckily for the lice-infested whales, other creatures go after the lice. Topsmelt are silvery fish that school in the breeding lagoons. Normally they feed on marine plants, tiny shrimps and other miniscule creatures of the lagoons. But when the whales are around, the topsmelt dine on the whales. How? Schools of these small fish pick at the barnacles and whale lice crusting up a whale’s skin. Topsmelt groom whales in the calving lagoons. By ridding the whales of some of their parasites and old, flaky skin, topsmelt may be helping to cut down the resistance, or drag, that grays create as their huge bodies move through the water. The whales have a smoother ride and the topsmelt groomers get protein-rich food.”

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.

December 2006

Idotea wosnesenskii: Isopod–The Race Rocks Taxonomy

Posted on by

 

1– Global Distribution: Ranges from Alaska (and Russia) to Estero Bay, San Luis Obispo County.

2- Habitat: You can find it under rocks, under cobble at the edges of tide pools, in blades of seaweed, attached to floats and on eelgrass. Hangs onto holdfasts stalks, worm tubes and other objects. But the most common place is under rocks on the shore.

3- Physical Description: They are large isopods, measuring up to 3-4 cm long and quite dark. Generally their color is olive-green but it may vary from bright green to brown or nearly black. The abdominal region is mostly unsegmented and their terminal portion is rather smoothly rounded, except for a tiny blunt tooth at the tip See the ventral image on the left.
4- Feeding: It feeds on algal detritus and reproductively mature plants, but avoids non-fertile individuals. It doesn’t eat immature plants by the algae’s cuticle.

5- Predators: Other arthropods and invertebrates, fishes, birds, reptiles and mammals.

6- Reproduction: “During reproduction, the male isopod carries the female for a short period known as pre-copula which lasts until the moult at which time copulation occurs. The sperm are transferred from the male to the female genital duct. In most species, the female releases the eggs into a ventral brood chamber where they are incubated until after hatching.” Idotea wosnesenskii incubate their eggs and juveniles in pockets of the body which open from the brood chamber. “Unlike crabs and shrimps isopods are not released as free-swimming zoea larva. Instead, when hatched they look very much like adults but have 6 rather than 7 pereonal segments. Some species care for their young after leaving the chamber but most species do not.” (Quoted from source b)

7- An Interesting Fact: It does not look like much of a swimmer, but it is surprisingly agile and graceful when it does swim. The paddlelike appendages on the underside of its abdomen propel it with seeming effortlessness, while the legs are spread as if to take hold of any firm object that comes along
8- References:

a) EZIDweb-Idotea wosnesenskii. October 1, 2002.
Webmaster: Beach Watcher Joan Gerteis. November 13th 2005.
http://www.beachwatchers.wsu.edu/ezidweb/animals/Idoteawosnesenskii2.htm
b) Biology of Isopods. 1996.
© Museum Victoria Australia. November 13th 2005.
http://www.mov.vic.gov.au/crust/isopbiol.html

c) Edward F. Ricketts, Jack Calvin, Joel W. Hedgpeth. Between Pacific Tides. 5th Edition.

d) Kozloff, Eugene N. Seashore Life of Pudget Sound, The Strait Of Georgia, and The San Juan Archipelago.

e) Yates, Steve. Marine Wildlife From Pudget Sound Through The Inside Passage.

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. This file was originally written by Claudia Aliaga, Chile, Pearson College student , Year 32 -2006

 

Lepeophtheirus.sp: Sea Louse–The Race Rocks Taxonomy

Posted on by
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:Helmet Crab-The Race Rocks Taxonomy

Posted on by
helmet crab

Telmessus cheiragonus

 

helmetventral

Telmessus cheiragonus, the helmet crab, ventral inage

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 photos 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

Posted on by
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.

Heptacarpus tenuissimus: The Race Rocks Taxonomy

Posted on by

 


A very small shrimp, not often noticed but probably common at Race Rocks.
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Family
Genus Heptacarpus
Species tenuissimus
Common Name:
slender coastal shrimp

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.

 March October 2003- 

Elassochirus tenuimanus The Race Rocks Taxonomy

Posted on by

Domain Eukarya
Kingdom Animalia
Phylum Arthroppoda
Class Malacostraca
Order Decapoda
Family Paguridae
Genus Elassochirus
Species tenuimanus
Common Name: Wide-hand hermit crab

In this video, Elassochirus has been disturbed from eating a limpet (Collisella instabilis). It recovers and returns to eating. Note the colouration of the appendages of the hermit crab. Also note that one arm is much wider than the other. The Collisella which normally has a pale shell, is encrusted with the pink algae Lithothamnion.

General Description:
Named as wide-hand, this species hermit crab has a large and flattened right side of chela, carpus and propodus more than its left side. The right cheliped has a wider carpus than it is long. The walking legs have colours of white, reddish brown and purplish-blue on its merus.

Size:
The exterior length is up to 42 mm (1.6 inches).

Natural History, Habitat and geographical and depth range:
Mud, sand, shell bottoms, and especially rocks. The depth range is intertidal (infrequently) to 388 m (1272 feet). For the geographical range, the hermit crab lives in Bering Sea and Aleutian Islands, from Alaska to Washington, and the northwestern Pacific.
Ovigerous females in Washington usually appear from August to May.  Larvae produce from March to May and Planktonic are in last months of the year.

Behavior
When the animal retreats inside, the right claw is used to block the access to the shell itself. The crab bents this claw beneath the body while walking.

References:
– Pacific Coast Crab and Shrimps, Gregory C. Jensen; Sea Challengers Monterey, California, 1995.

– Marine Invertebrate of the Pacific Northwest, Eugene N. Kozloff; University of Washington Press, Seattle and London, 1996.

http://people.wwc.edu/staff/cowlda/KeyToSpecies/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/
Eucarida/Decapoda/Anomura/Family_Paguridae/Elassochirus_tenuimanus.html

 

Lopholithodes mandtii : The Puget Sound King Crab–The Race Rocks Taxonomy

Posted on by

We often encounter these very large Puget Sound King Crabs in the calm backwaters of Race Rocks. Juveniles may be found among the cobble. Sea urchins and other echinoderms form their diet.

 

Paul Michaluk a fomer PC student from New Zealand, captured this picture on the left of Garry holding a  a Lopholithodes brought up by the divers who were back for a PC alumni reunion

Another former student, Barb Holman, took the picture on the right of Garry demonstrating the size of a Puget Sound King crab at Race Rocks to Trish Holman in April, 1998
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Order Decapoda
Family Lithodidae
Genus Lopholithodes
Species mandtii
Common Name: Puget Sound King Crab

See a post by our ecoguardian Mike Robinson in 2012

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. 

 

Caprella laeviuscula: Caprellid shrimp– The Race Rocks Taxonomy

Posted on by

We found these Caprellids at a depth of 20 metres attached to hydroids on a Balanus nubilus. They frequently dwell amongst hydroids. The size of this individual was 3mm. These individuals were photographed using a Motic Digital Microscope at 10X magnification. Note the response to stimulation by a dull probe.

In the picture below , the current meter float which was in the water for a year, came up covered with Caprellids. See this file on the Current meter:

Look closely to see these tiny skeleton shrimp clinging to bryozoans, hydroids or algae. Their body shape and color help the shrimp to blend into their background. Their bodies are long, cylindrical and range from pale brown and green to rose. Some species can quickly change color to blend into their backgrounds.

Skeleton shrimp look like, and sometimes are called, “praying mantises of the sea.” They have two pairs of legs attached to the front end of their bodies, with three pairs of legs at the back end. The front legs form powerful “claws” for defense, grooming and capturing food. The rear legs have strong claws that grasp and hold on to algae or other surfaces. They use their antennae for filter feeding and swimming.

Diet
diatoms (microscopic plants), detritus, filtered food particles, amphipods 
Size
to 1.5 inches (4 cm) long 
Range
low intertidal zone and subtidal waters in bays,

Conservation Notes

Skeleton shrimp are abundant and live in many habitats, including the deep sea. They play an important role in the ecosystem by eating up detritus and other food particles. 

Cool Facts

Shrimp, sea anemones and surf perch prey on skeleton shrimp. The females of some skeleton shrimp species kill the male after mating. 

Skeleton shrimp use their front legs for locomotion. To move, they grasp first with those front legs and then with their back legs, in inchworm fashion. They swim by rapidly bending and straightening their bodies. 

To grow, skeleton shrimp shed their old exoskeletons and form new, larger ones. They can mate only when the female is between new, hardened exoskeletons. After mating, the female deposits her eggs in a brood pouch formed from leaflike projections on the middle part of her body. Skeleton shrimp hatch directly into juvenile adults.

Source: Monterey Bay Aquarium:
Online Field Guide http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=521

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. This file was originally started by Kevin Mwenda PC Yr 31

Caprella laeviuscla: Smooth skeleton shrimp

Posted on by

Skeleton shrimp Caprella laeviuscula

 

We found these Caprellids at a depth of 20 metres attached to hydroids on a Balanus nubilus. They frequently dwell amongst hydroids. The size of this individual was 3mm. These individuals were photographed using a Motic Digital Microscope at 10X magnification. Note the response to stimulation when disturbed by a dull probe.

 

Garry and a Pearson College diver, stabilize the Institute of Ocean Sciences float before hauling it into the boat, This was at the end of one year of monitoring the tidal currents. From this process the Current Tables for Race Passage were developed by IOS.

This Post tells the story of the Current Meter Installation :

Look closely to see these tiny skeleton shrimp clinging to the bryozoans,The  shape and color help the shrimp to blend into their background. Their bodies are long, cylindrical and range from pale brown to green Some species can quickly change color to blend into their backgrounds.

Skeleton shrimp look like, and sometimes are called, “praying mantises of the sea.” They have two pairs of legs attached to the front end of their bodies, with three pairs of legs at the back end. The front legs form powerful “claws” for defense, grooming and capturing food. The rear legs have strong claws that grasp and hold on to algae or other surfaces. They use their antennae for filter feeding and swimming.

Diet
diatoms (microscopic plants), detritus, filtered food particles, amphipods
Size
to 1.5 inches (4 cm) long
Range
low intertidal zone and subtidal waters in bays,

Conservation Notes

Skeleton shrimp are abundant and live in many habitats, including the deep sea. They play an important role in the ecosystem by eating up detritus and other food particles.

Cool Facts

Shrimp, sea anemones and surf perch prey on skeleton shrimp. The females of some skeleton shrimp species kill the male after mating.

Skeleton shrimp use their front legs for locomotion. To move, they grasp first with those front legs and then with their back legs, in inchworm fashion. They swim by rapidly bending and straightening their bodies.

To grow, skeleton shrimp shed their old exoskeletons and form new, larger ones. They can mate only when the female is between new, hardened exoskeletons. After mating, the female deposits her eggs in a brood pouch formed from leaflike projections on the middle part of her body. Skeleton shrimp hatch directly into juvenile adults.

Source: Monterey Bay Aquarium:
Online Field Guide http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=521

Also see:

http://www.nwmarinelife.com/htmlswimmers/c_laeviuscula.html

 

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
SubclassEumalacostraca
SuperorderPeracarida
Order Amphipoda
SuborderCaprellidea
InfraorderCaprellida
Family
Genus Caprella
Species laeviuscula
Common Name: Smooth skeleton shrimp

 

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. March 15 2005- Kevin Mwenda- Pearson College Year 31.