Linckia guildingii

Geographic Range

Linckia guildingii is found in the Atlantic Ocean from Florida to Brazil, and around the Caribbean islands. It is also found in Australia (the Great Barrier Reef). Linckia guildingii usually inhabits shallow depths of about 1 meter, but has been found at a depth of over 100 meters.

• Biogeographic Regions
• atlantic ocean atlantic ocean
  • native native

Habitat

Linckia guildingii primarily lives on the hard, flat bottom of coral reefs, but may also be found on slopes and sandy regions. Usually it is hidden, but may be exposed.

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

• Aquatic Biomes
• reef reef
• coastal coastal

Physical Description

Linckia guildingii has 4-7 cylindrical arms of uneven length (up to 22 cm long). It is comet shaped (a star with a long tail) which is caused by its asexual mode of reproduction. This tail is the longest arm that came from the parent, while the "star" is composed of smaller, regenerated arms. However, this species may have a more symmetrical star shape at a different stage. Coloration changes with maturity. The adult is uniform and characteristically gray. Reddish brown, yellowish brown, tan, or violet adults also occur. Juveniles, however, are mottled white, gray, purple, violet, red or brown.

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

Development

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Both sexual and asexual reproduction occur in this species; however, asexual reproduction is the dominant form. Arms voluntarily detach to form a new individual (known as autotomy). The new "daughter" has an identical genetic makeup to the parent.

In sexual reproduction, the sexes are separate. The females release many eggs. They are colorless and about 0.1 mm in diameter. The eggs are negatively buoyant upon leaving the female's gonopores (found on the arms). The development of larva is planktotrophic, meaning the larvae primarily survives by feeding on plankton.

Males have serially arranged gonads, with each arm containing several gonoducts. The gonads are particularly dominant before they spawn. At this time, gametes are released in the water, resulting in external fertilization. Some research has been done on the effect of the hormone 1-methyl adenine. When injected with the hormone, the starfish released their gametes, usually within three hours. The results varied depending on proximity to the natural mating season. For L. guildingii, the peak was in mid-summer in Australia (December).

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

• Parental Investment
• no parental involvement

Behavior

This is a bottom dwelling species that moves from its cover to feed. It usually stays hidden to avoid predation by fish.

• Key Behaviors
• motile motile
• sedentary sedentary

Food Habits

Linckia guildingii everts it stomach which excretes digestive juices to break down foods externally. Some food may be gathered from dead fish. However, the primary food source is from epibenthic felt (made up of protozoans, algae, and bacteria). Hard surfaces like coral-rock and sand are covered with a layer of this organic material. Linckia guildingii was proposed to be a filter (ciliary) feeder, and s generally thought to be a detritivore (eating felt). Linckia guildingii has a smaller cardiac stomach (large oral chamber) and larger rectal caeca (small outpocketings in in the intestine) when compared with other species.

• Primary Diet
• carnivore carnivore
  • scavenger scavenger
• omnivore omnivore
• detritivore detritivore

• Plant Foods
• algae

• Other Foods
• detritus detritus

• Foraging Behavior
• filter-feeding filter-feeding

Economic Importance for Humans: Positive

Only small economic benefit is gained through the sales of L. guildingii . They may be purchased as pets for aquariums and are sold under the common name "comet stars."

Economic Importance for Humans: Negative

Linckia guildingii causes no negative effects on the economy.

Conservation Status

Some conservation efforts have recently been started in Puerto Rico and the U.S.Virgin Islands. In 1999 a Marine Conservation District (MCD) was established that prohibits fishing or anchoring of fishing vessels in an area around St. Thomas and the U. S. Virgin Islands. Numerous reef animals are being protected from pollution and harvest for aquarium sale.

Other Comments

Linckia guildingii and Ophidiaster guildingii are two similar species that are often confused due to coloration and location. Ophidiaster guildingii , however, has arms of equal length. They also have 15 pores per papular area, and L. guildingii can have up to 30.

Additional Links

Encyclopedia of Life

Contributors

Renee Sherman Mulcrone (editor).

Adrianne Stropes (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

References

Charonia Research, 1996a. "Coral Reef Starfish, Chapter 3: Habitat" (On-line). Accessed 07/15/04 at http://www.charonia.com/charonia/chap3.htm .

Charonia Research, 1996c. "Coral Reef Starfish, Chapter 6: Sexual Reproduction" (On-line). Accessed 07/15/04 at http://www.charonia.com/charonia/chap6.htm .

Charonia Research, 1996b. "Coral Reef Starfish, Chapter 7: Asexual Reproduction" (On-line). Accessed 07/15/04 at http://www.charonia.com/charonia/chap7.htm .

Charonia Research, 1997. "Starfish species: *Linckia guildingii*" (On-line). Accessed 07/15/04 at http://www.charonia.com/charonia/species.htm .

Clark, A. 1977. Starfishes and Related Echinoderms . New Jersey: T.F.H.Publications, Inc., Ltd..

Department of Commerce, , National Oceanic and Atmospheric Administration. 1999. "Coral Reef Resources of Puerto Rico and the U.S. Virgin Islands; Initial Regulations; Federal Register 64 (213): 60132" (On-line). Accessed April 11, 2003 at http://www.epa.gov/fedrgstr/EPA-IMPACT/1999/November/Day-04/i28830.htm .

Grzimek, B. 1972. Grzimek's Animal Life Encyclopedia . New York: Van Nostrand Reinhold Company.

Hendler, G. 1995. Sea Stars, Sea Urchins, and Allies: Echinoderms of Florida and he Caribbean . Washington: Smithsonian Institution.

Jangoux, M., J. Lawrence, eds.. 1982. Echinoderm Nutrition . Rotterdam, Netherlands: A.A.Balkema.

Meinkoth, N. 1981. The Audobon Society Field Guide to North American Seashore Creatures . New York: Alfred A. Knopf, Inc..