Category Archives: Phylum Echinodermata

Pycnopodia helianthoides: Sunflower star–The Race Rocks taxonomy

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Pycnopodia tend to be found thriving in regions rich in seaweed, in low intertidal zones on rocky shores. They have an arm radius that ranges from forty to sixty-five centimeters. Small juveniles have five arms but develop twenty four by the time they are adults. Pycnopodia have an aboral surface and are usually pink, purple or brown in color. Occasionally they will be red or yellow in color. They also have the ability to regenerate lost arms. Pycnopodia are the largest, heaviest and most active of the Pacific coast sea stars. Pycnopodia feed on Stronglyocentrotus purpuratus (the purple sea urchin), bivalves, polychaetes, chitons, snails, hermit crabs, crabs, sea cucumber, and Leptasterias sea stars . The Pycnopodia utilize over fifteen thousand sucker feet when capturing prey. Their prey is swallowed whole and digested internally, and they have the ability to partially evert their stomach. Antagonistic, combative behavior has been observed when two Pycnopodia encounter one another. The key predator of the Pycnopodia is the King Crab. A fourfold increase in speed has been noted when the Pycnopodia is in contact with a predator. If the Pycnopodia does not escape, the predator will latch on to one of its many arms and begin to feed.

The sea star Pycnopodia helianthoides is one of the largest invertebrate predators at Race Rocks. In this close up view, on the dorsal side, the pinkish tufts contain the pedicellariae (small pincers) and the dermal branchiae (for gas exchange) On the ventral view, the central mouth is surrounded by many tube feet.

In October, 2001, federal Fisheries Minister Herb Dahliwal and the Provincial Environment Minister Joan Sawiki visited Race Rocks to officially proclaim the opening of the Race Rocks MPA. In this video, Ryan Murphy shows the ministers a Pycnopodia.

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroidea
Order Forcipulatida
Family Asteriidae
Genus Pycnopodia
Species helianthoides
common nameSunflower Star

References cited:

Marine Invertebrates of the Pacific Northwest, Eugene N Kozloff, 1996, University of Washington Press
Intertidal Invertebrates of California, Robert H Morris Donald P Abbot and Eugene C Haderlie, 1980, Stanford University Press
Pacific Seashores- A Guide to Intertidal Ecology, Thomas Carefoot, 1977, J.J. Douglas Ltd

 

Other Members of the Phylum Echinodermata 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 2001-  Hannah McKinnnon (PC)

Gorgonocephalus eucnemis: Basket star-The Race Rocks taxonomy

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What are basket stars ?

Basket stars are entirely marine invertebrate animals with a pentaradial symmetry. Their bodies are composed of a central disk with multitudes of arms branching dichotomously forming thousands of branchlets. The central disk can be approximately 14cm and the arms 4-5 times the length of the disk. Their colours vary between individuals and often on different parts of the body ranging from beige to almost white.
Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Ophiuroidea
Order 0phiurida
Suborder Euralina
Family Gorgonocephalidae
Genus Gorgonocephalus
Species eucnemis
Common Name:Basket Star

Habitat.

Can be found in rocky intertidals in areas with high high currents only (~10cm/s or more ). Juveniles typically cling to adults and on octocoral colonies ,while adults locate crevices in which to hide during day and then climb to an elevated point to feed at night.

How do they feed ,On What and When.

When feeding, they extend several of their arms into the water, the branchlets spread out like a fan, oriented so that they are more or less perpendicular to the water current. Macroscopic zooplankton including chaetognaths are caught by an array of microscopic hooks on the arms. Branchlets in the vicinity curl and wrap around captured prey forming a localized knot. Mucus extruded from glands further immobilise the prey. At some point knot-laden arms roll in towards the underside of the disk and the captured prey is transferred to the mouth. At the mouth there is a comb like structure the arms pass through to remove all the trapped prey. The prey is then ingested as the arm is redeployed. The gut is very simple and is contained entirely within the central disk hence if the disk is not puffy and inflated the star is starving.

Reproduction and feeding in Basket stars .

This is an example of a juvenile basket star, nestled into the lobes and surrounded by the polyps of the soft pink coral, Gersemia rubiformis.
G.Fletcher photos.

The sexes are separate and they spawn planktonic larvae. They can grow back their limbs if they happen to get chopped off .They also have tube feet and a water vascular system and also pedicellariae for protection. They are also filter feeders and they have a one way digestive system -meaning that the mouth performs the functions of a mouth plus those of an anus .

Who Preys on them?

Though they are cryptic and difficult to spot, they do have predators. Their main predators are fish and other invertebrates like crabs . There actually isn’t much to eat in a basket star but evidence suggests that most contents of some fish guts are basket star arms .

Biological association.They have mutualistic relations with other animals particularly sponges and Gthe soft coral, Gersemia. In such relationships, both the star and the host animal benefit. They either hide underneath the sponge (because it is poisonous and only a few animals other animals can dare touch it), or they live in canals or openings in sponges called ostia . The star thus gains protection from predators and at night it is usually seen sweeping over the surface of the sponge removing the large debris clogging the sponge and consumes it, and once again the star gains something –food. However, the sponge also benefits in that it gets cleaned whereas if it had continued clogged with debris as it was, its feeding efficiency would be reduced since it’s a filter feeder

References

www.reefs.org–(date-1/31/02) ,

Intertidal Invertebrates of California –(Robert H .Morris et.al.)

Other Members of the Phylum Echinodermata 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.

 February-2002- Moreblessing Nkomo (Zimbabwe) (PC yr 28)

Ophiothrix spiculata: Brittle star–The Race Rocks Taxonomy

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Ophiothrix spiculata is a common species among algal holdfasts at Race Rocks. Its arm’s spines are especially long, and each one has a number of small thorns on it. the color is extremely variable but it is generally reddish brown, there may be some orange on the disk, too. in spite of all the color variation, this species is unmistakable because of its thorny spines.

Two sets of video on brittle stars are seen here. They were observed off the docks at Race Rocks in about 10 meters of water. Note the other organisms that live in the area also.

 

This brittle star is lives on the rocky sea floor, from shallow waters to great depths. Brittle stars are related to sea stars. These marine invertebrates move very slowly along the sea bed. More than 2000 species of brittle stars exist in the world.
It has long, thin, spiny arms that radiate from a flat central disk; the arms do not touch each other at their bases. Many of the arms are forked. If a brittle star’s arm is cut off, it will regenerate.
Usually the central disk in these brittle stars is under 2 cm) in diameter. They have an exoskeleton and vary in color. They do not have a brain; they have a simple ring of nerve cells that moves information around the body. Tube feet located along the arms sense light and smells.

This juvenile brittle star was filmed in the lab by Sylvia Roach using a Digital camera attached to a dissecting microscope at 4X

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Ophiuroidea
Order Ophiurida
Family Ophiodermatidae
Genus Ophiothrix
Species spiculata
COMMON NAME: brittle star

They often gather in large groups and collectively filter food from the circulating water. When roused from a hiding spot their best form of defense is to crawl away-

The projections on the five arms of this brittle star look like many tiny hairs, but are actually spines. That being said, they are gentle, very delicate creatures that do not harm humans. They are nocturnal (feed and move about primarily at night); they stretch out to catch food particles, passing the bits down to the central mouth.
To avoid predation, if a predator catches one of its legs, it has the ability to swim off, leaving that leg behind, and it can regenerate a new one!

Waving arms point out the home of the stars. Those aren’t worms, they’re brittle stars, sea star cousins that hide themselves under rocks and in the holdfasts of kelp, especially in the Pterophyga at Race Rocks.

For comparison with another species, see this image in our ecological equivalents file an image of a large 20cm species from the Galapagos:

 

 

 

Reference Cited:

Eugena N. Kozloff , Seashore Life of the North Pacific Coast

http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=142

 

Other Members of the Phylum Echinodermata 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-  Rahilla (PC)

Leptasterias hexactis The Race Rocks Taxonomy

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The six rayed sea star is found both intertidally and subtidally at Race Rocks. They are one of the smaller sea stars.

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroidea
Order Forcipulatida
Family Asteriidae
Genus Leptasterias
Species  hexactis  (Stimpson,1862)
COMMON NAME: Six- rayed Star
Introduction
Description: Radius 2″ (51 mm), 6-armed ( note the species name hexactis referring to the six arms.). Green, black, brown, or red, sometimes mottled. Disk moderate-sized with 6 fairly broad arms; spines on upper surface dense and mushroom-shaped. rarely do we find these at Race Rocks exceeding 15 cm in length.
Habitat: On rocky shores. We frequently find these when doing intertidal studies or when diving in shallow water at Race Rocks. Range British Columbia to s. California.
Discussion: L. hexactis eats small snails, limpets, mussels, chitons, barnacles, sea cucumbers, and other species, including dead animals. It produces yellow, yolky eggs that stick together in a mass after fertilization. These are brooded under the disk of the female until they hatch as miniature sea stars after 6 to 8 weeks. The small six-rayed sea stars of the West Coast are quite variable and have presented problems of identification. The only other species currently recognized is the Small Slender Sea Star (L. pusilla) which has sharp spines and longer, thinner arms than L. hexactis, and is a light gray-brown or reddish color. It also has a very limited range from San Francisco to Monterey Bay. It reaches a radius of 1″ (25 mm).
Echinoderms have a few important aspects in common. They have bony ossicles in their body. They have a water-vascular system which pumps water through the madroporite. They also have small jaws that are supported by the water-vascular system. And they have tube feet which they use to attach to objects, for protection, as well as to obtain food. They have radial symmetry and most can regenerate lost limbs.

 

Other Members of the Phylum Echinodermata 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 2001(PC)

Mediaster aequalis: Vermillion star–The Race Rocks Taxonomy

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Mediaster in its habitat. Photo by Dr.A..Svoboda

Snail predation

 

Vermillion stars are seen frequently by divers in the 0-15 meter depth at Race Rocks.

 

Information.
Bright red (vermillion in fact) with large plates along its five arms. To 20 cm. Common just below the surface on low tides but hardly ever high and dry. These are abundant subtidally – you may find plenty after storms or extreme tides.

This Vermillion star male was emitting sperm while in the tank at Pearson College in early January 2004 . This went on for more than three hours. Millions of sperm are broadcast into the water where they may have a chance encounter with eggs which are simultaneously released into the current by the females. Of the great numbers of eggs and sperm released only a few are fertilized and actually make it to maturity. This is a good example of
r-selection in the population.

– http://www.wavelengthmagazine.com/1998/jj98neigh.htm

Mediaster aequalis is one of the smaller sea stars ranging in size from three to seven inches. It is found on many types of beaches at very low tides.

– http://www.geocities.com/oscmarinetech/Animals.htm#Vermillion%20Star

The vermillion sea star is common in shallow subtidal waters. Its feeding area stretches to nearly the tip of each arm on the underside. The vermillion star, so named because of its colour can be found from the Alaskan Peninsula, south to southern Caifornia.

Colour: Vermillion aborally, more orange orally; tube feet red to flesh colour.

Habitat: common on rocks shell, sand, gravel, pebbles and mud.

Feeding: diet varies with substrate and season; eats encrustin sponges and bryozoans on ock; seapen.

Reproduction: breeds from March to May; number of eggs in 65mm sea star estimated at 1,800 per year. the eggs measure 1 to 1.2mm and are bright opaqe orange. It is estimated that Vermillion sea stars reach sexual maturity within four years.

Speed: The sea star can move anywhere between 27 and 40 cm per minute.

Reference: The Sea Stars of British Columbia, Lambert, 1981, British Columbia Provincial Museum, Victoria

Other Members of the Phylum Echinodermata 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.

Dec 2001 Damien Guihen (PC yr 27)

Henricia leviuscula The Race Rocks Taxonomy

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Blood stars are seen frequently by divers in the 0-15 meter depth at Race Rocks. They are planktonic feeders.

Kingdom Animalia
Phylum Echinodermata
Class Stelleroidea
Sub Class Asteroidea
Order Spinulosida
Sub Order Leptognathina
Family Echinasteriade
Genus Henricia
Species Leviuscula
Common Name Blood Star

The Blood Star is characterized by its brilliant red or reddish-orange color. Its comparatively small and graceful its body is only 10 to 12 cm from the tip of one ray to the tip of the one across from it. It has an arm radius to 8.9 cm, usually less; its disk is small, its arms are long, tapering, and are usually five in name (sometimes four or six); it has an absent pedicellariae; its aboral surface has a tan to orange-red or purple color., often banded with darker shades, and bearing many groups of short spinlets arranged in a fine network.
Habitat: Common on protected sides of rocks, under rocks, and in caves and pools, more frequently where rock is encrusted with sponges and bryozoans, low intertidal zone, subtidal to over 400 m.

The sea star feeds on bacteria and other tiny particles, which are captured in mucus and swept to the mouth by ciliated tracts. It may also feed by applying the stomach to the surfaces of sponges and bryozoa.

Breeding habits in the sea star vary with size. Smaller females brood their eggs in a depression around the mouth formed by arching the arms. Larger females discharge eggs directly into the water and do not brood them. The sperm have spherical heads and the eggs are orange-yellow and yolky, and development is direct.

REFERENCES CITED:

1. Robert H. Morris, Donald P. Abbott, and Eugene C. Haderlie,Intertidal Invertebrates of California, 1980, Stanford University

LINKS:

http://elib.cs.berkeley.edu/photos/fauna/sci-invertebrate.html

http://enature.com/fieldguide/showSpeciesSH.asp?curGroupID=
8&shapeID=1072&curPageNum=9&recnum=SC0074

Other Members of the Phylum Echinodermata 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.

 Dec 2001Tania Melendez (PC yr.27)

Strongylocentrotus purpuratus: Purple sea urchin– The Race Rocks Taxonomy

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Purple Urchins and Californianus sp mussels at a “zero” level tide on the west side of Great Race Rocks.
July 2000

The purple sea urchin is about 10 cm. across, spines up to 2cm. and is bright purple. Its body “skeleton”, called the test, is shell like with bumps and holes from which the moveable spines and tube feet extend .The spines are used for protection, movement and for trapping drifting algae. It has a claw like mouth with 5 teeth-like plates. It is composed of over 60 shells and is called Aristotle’s lantern and is located on the underside or oral side of its body. The anus and the genital pores are on the aboral side of the sea Urchin.

In February, 2004 we had a note from CECIERJ requesting permission to use our video of the purple sea urchin in media being prepared for their undergrad distance learning courses. By offering these courses, the consortium CEDERJ contributes to bringing high quality free education to the inner cities of the Rio de Janeiro State. As well as permitting such use of our resources, we have added for them, an introduction by one of our Brazilian students, Rita who helped us make this video in Portuguese about the Sea Urchins and Echinoderms..

Diet: The Sea Urchin feeds on algae, plankton, kelp, periwinkles, and occasional tiny barnacles or mussels.

They are eaten by crabs, sunflower stars, snails, sea otters, some birds, fish, and people.

Reproduction: Fertilization in Sea Urchin is external, the female release several million tiny, yellow jelly-coated eggs at a time. The gametes join the water column as planktonic forms .

Behaviour: Although they often live in sheltering holes that they have worn in the rocks and they have also been observed to makes holes in solid steel, this behaviour is not evident at Race Rocks. Most of them live in shallow water here, They move surprisingly fast on their tube feet and spines. Moving their feet by a hydraulic water vascular system which creates suction in the end of the foot by pulling water out of the madreporite. They can also regrow broken spines.

The following images show the structural features on the test of a dead purple sea urchin. The image was produced by scanning.


This image shows the aboral view of a purple sea urchin.The dark patch in the middle is the anus. These were dead specimens.Thus the spines are missing.

Domain Eukarya
Kingdom Animalia
Phylum Ecinodermata
Class Echinodea
Order Echinoida
Family Strongylocentrotidae
Genus Strongylocentrotus
Species purpuratus
common name Purple Sea Urchin

The lower image shows the oral view of a purple sea urchin. The hole in the middle is its mouth with the sharp edges its 5 teeth. Note the pentaradial symmetry.

Parastichopus californicus The Race Rocks Taxonomy

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 Video of Albinism and Leucism in Sea Cucumbers

 

 

 

 

Video of escape response when attacked by Pycnopodia sp.

 

 

 

 

Video of a male sea cucumber releasing sperm

 

 

 

Emily finds a partially albino (pinto?) Parastichopus while diving near Church Island… just up the Strait from Race Rocks. 

 

 

DESCRIPTION:

The California Sea Cucumber grows up to 50cm long. They are the largest cucumbers in B.C. waters. They range in colours from red in juveniles to brown or mottled brown, with all white individuals occurring rarely. They are covered on the dorsal side with flesh coloured papillae, and on the ventral side by tube feet. A circle of peltate feeding tentacles surround a subterminal mouth, directed ventrally at the anterior end. Oxygenated water is forcibly pumped into the sea cucumber’s respiratory trees in several successive inhalations, and then deoxygenated water is forcefully expelled. Eye-witness accounts have noted small fish being expelled with this force of water, perhaps living in symbiosis with the California sea cucumber.

RANGE:

Gulf of Alaska to Cedros Island, West of Lower California. Intertidal to 249m. Common on mud, gravel, shell, rock rubble or solid bedrock, from exposed coast to sheltered inlets. Greatest densities occur in quieter waters where organic sediments settle on hard surfaces. Harvesting of Sea Cucumber is also done by divers, throughout their range.

FEEDING, BEHAVIOR, AND BREEDING:

Sea cucumbers feed as they move along the bottom, traveling up to a maximum of 3.9m a day. They gain nutrition from organic material in sediment, mostly form bacteria and fungi. California Sea Cucumbers cease feeding and become dormant from September to early March. Once they reach maturity at four years of age, they will migrate to shallow water to spawn from late April to August, although this timing varies with location. Fertilization takes place in open water. Free swimming larva feed on plankton for 35-52 days before settling to the bottom. Parastichopus californicus has few natural predators. Sunflower starts sometimes eat them, and the sea cucumber reacts strongly by rearing back and flexing violently to avoid being eaten. They are harvested commercially in B.C., Washington, and Alaska for meat, and limits have been set for the amount that may be caught. When disturbed, as other sea cucumbers, it will contract and squirt a powerful stream of water from its posterior end. Five pairs of muscle bands which run the length of the body help this organism in contracting and escape from sea stars. Perhaps one of the most interesting features is this organisms ability to regenerate new organs for winter after expelling them during its dormant phase. It seems there is controversy as to whether sea urchins expel or reabsorb their organs. Recent evidence cited by Philip Lambert of the RBC museum in Victoria(1997) indicates that the sea cucumbers reabsorb their organs.

FURTHER INFORMATION NEEDED:

-further study at Race Rocks of commensal fish living in respiratory tree

-behaviour studies

-colouration, how long it takes to occur in full pigmentation, as a white individual found near Race Rocks has recently begun to change tan colour–later development?

-mechanism of absorbing/ejecting and regenerating organs

WEBSITE LINKS TO SEA CUCUMBERS:

Sea cucumber fishery – Pacific Region
http://www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/Sea_Cucumber/biology_cucumber.htm

A paper by Phil Lambert on Sea Cucumber Taxonomy
http://rbcm1.rbcm.gov.bc.ca/nh_papers//taxing.html

REFERENCES CITED:

Carefoot, Thomas (1977), Pacific Seashores : A Guide to Intertidal Ecology
Lambert, Philip (1997), Sea Cucumbers of B.C., Southeast Alaska and Puget Sound
Morris, Abbott, Haderlie (1990), Intertidal Invertebrates of California
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.  – Sarah Trefry Dec 2001 (PC)

Other Members of the Phylum Echinodermata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File