Luidia ciliaris

Geographic Range

Located in parts of the Mediterranean Sea and the Atlantic ocean, these starfish can withstand both tropical and temperate or subboreal environments. They are most frequently found on the coast of Europe, including the British Isles, and have been seen as far north as the Shetlands, and as far south as Cape Verde.

• Biogeographic Regions
• atlantic ocean atlantic ocean

Habitat

The areas on the shores where Luidia ciliaris is native tend to be rough, sandy and shallow. The star lies scarcely burried under the sand. While Luidia ciliaris can live at depths ranging from four to four-hundred meters, it prefers the range of about fifty to one-hundred meters. These places are favorable to L. ciliaris because they provide a flourishing food source.

• Habitat Regions
• temperate temperate
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• coastal coastal

Physical Description

Luidia ciliaris is red-orange and has radial heptamerous symmetry in the adult stage. It consists of a small disk-shaped frame of plates (their mouth) surrounded by seven slighty-tapered tubular arms (each ranging in length from approximately 5-25 cm.) These tube arms lack suckers, and have double ampullae (two sets of terminal bulbs on each arm). Along each muscular arm is a band of long white spines. The arms are important to the creatures' attacks for food and escape from predators, and in almost all cases Luidia ciliaris is found, it either has an injured arm, or signs of regrowth of an arm. The internal systems of these animals have no intestine, ceca, or anus, and their gonads are arranged in a double series along the length of their arms.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• radial symmetry radial symmetry

Development

During the summer, new L. ciliaris zygotes are formed. These coelomates are part of one of the only two deuterosome phyla. They develop into fully functioning bipinnaria larvae after about three to four days. The larvae are very large and elaborate, and can reach up to thirty-five millimeters in length. These larvae live in their plankton feeding ground until they grow into a complete starfish (around four months from around July to October).

Reproduction

The sexual reproduction of Luidia ciliaris is similar to the reproduction of most other starfish. The starfish gonads are arranged in a double series along the length of their arms. Fertilization of the females' eggs takes place in open water. The males' sperm is stimulated to be released following the egg release. To improve chances of the gametes meeting in the water, millions of eggs and sperm are released by each female and male.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external

There is no parental involvement after release of gametes in this species.

• Parental Investment
• pre-fertilization
  • provisioning

Lifespan/Longevity

These starfish live from 2 to 3 years.

Behavior

Luidia ciliaris has both a high rate of movement as well as a high metabolic rate. It pushes itself up on its seven arms with its center vertically raised; this strange walking stance helps the starfish get lift-off which aids in its ability to move quickly.

• Key Behaviors
• motile motile

Communication and Perception

Their strange walking stances can be a warning to animals nearby that the starfish is on the chase or is about to attack. Asteroids in general can sense light, chemicals in the water, and respond to tactile stimulation.

• Communication Channels
• tactile tactile
• chemical chemical

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

Similar to most starfishes, Luidia ciliaris is predatory. Foods eaten include heart urchins, brittle stars, the common starfish, the spiny starfish and many other enchinoderms.

The asteroid, which is present in low numbers throughout the year, forages in groups during the summer months. They are voracious carnivores, whose quick movements help them leap on top and devour their prey. Luidia ciliaris also has the ability to distort or even rupture the disk-shaped frame of plates of their mouths, allowing them to swallow very large prey. The seven-armed creature has been shown to prefer consuming brittle stars ( ophiuroids ) over other echinoderms in lab tests. As an example the ability of L. ciliaris to stretch its mouth, brittle stars can be up to almost twelve inches in diameter and can be fully injested by the carnivore. While known to feed on a variety of species of Echinodermata , L. ciliaris avoids those that secrete highly acidic mucus.

Larval Luidia ciliaris feed on plankton.

• Primary Diet
• carnivore carnivore
  • eats non-insect arthropods
  • eats other marine invertebrates
• planktivore planktivore

• Animal Foods
• aquatic crustaceans
• other marine invertebrates
• zooplankton zooplankton

Predation

Luidia ciliaris escapes predators because of its inconspicuousness, its protective calcite skeleton, and because it is fairly fast moving (compared to most starfish). This species is also able to escape from predators because of its ability to regenerate lost body parts within a matter of a few weeks or months.

Ecosystem Roles

Along the coast of the Western English Channel, Luidia ciliaris has a major role in the changing numbers of the sea shore's food chain. Luidia ciliaris shows a roughly inverse relationship to the abundance of Ophiothrix fragilis [brittle star]. In the last century, the numbers of this brittle star have steadily decreased while the number of Luidia ciliaris have increased in this area.

Economic Importance for Humans: Positive

The seven-armed starfish plays an important role in the food chains of the North Atlantic and Mediterranean coasts of Europe and surrounding areas, helping keep the spiny brittle stars from overpopulating these waters.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

A food source of L. ciliaris , Ophiothrix fragilis , plays a role in cleaning sponges (Porifera) in the sea. These sponges are useful to humans in that they filter water as it moves through their bodies, and by decreasing brittle star numbers in some areas, the seven-armed animals are affecting the efficiency of the natural water cleaners.

Conservation Status

Additional Links

Encyclopedia of Life

Contributors

Renee Sherman Mulcrone (editor).

Jessica Waldrop (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

References

B. E. Piction Co., 1996. "Echinodermata: Starfish, Sea Urchins etc." (On-line). Accessed October 2, 2001 at http://www.itsligo.ie/biomar/echinode/LUICIL.htm .

Brusca, R., G. Brusca. 2003. Invertebrates . Sunderland, Massachusetts: Sinauer Associates, Inc..

Catala, R. 1986. _Treasures of the Tropic Seas_, pg. 220 . New York: Times Editions.

Grzimek, B. 1972. _Grzimek's Animal Life Encylopedia_: Vol. 3 Mollusks and Echinoderms, pg. 365, 377, 387 . New York: Van Nostrand Reinhold Company.

Hendler, G., J. Miller, D. Pawson, P. Kier. 1995. _Sea Stars, Sea Urchins, and Allies_ . Washington: Smithsonian Institution.

Howson, C., B. Piction. 1997. _The Species Directory of the Marine Fauna and Flora of the British Isles and Surrounding Seas_, pg. 359 . North Ireland: Ulster Museum publication.

Monterey Bay Aquarium Foundation, 1999. "Brittle Star: {Ophiothrix spiculata}" (On-line). Accessed October 3, 2001 at http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=142 .

Nichols, D., J. Cooke. 1971. _The Oxford Book of Invertabrates_, pg. 181 . New York: Oxford University Press.

Parker, S. 1982. _Synopsis and Classification of Living Organisms_: Vol. 2, pg. 796 . New York: McGraw-Hill Book Co..

UK Marine Special Areas of Conservation, 2001. "The Western English Channel: Changes in Predation Intensity" (On-line). Accessed 12/10/04 at http://www.ukmarinesac.org.uk/communities/subtidal-brittlestar/bs4_1.htm .