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Aiptasia pallidapale anemone

By Caitlin Vaughn

Geographic Range

Aiptasia pallida is found on the southern United States Atlantic and Gulf coasts from North Carolina to Texas, as well as in the coastal Caribbean. (Colin, 1978)

Habitat

Pale anemones are found on mangrove roots, dead coral, and rocks (Kaplan, 1982). They form dense patches as crowded colonies or continuous sheets from below low water to the muddy zone (Stephenson and Stephenson, 1952). (Kaplan, 1982; Stephenson and Stephenson, 1952)

Physical Description

Aiptasia pallida is brownish or whitish and translucent (Kaplan, 1982), but often appear pale orange beneath the water (Stephenson and Stephenson, 1959). Usually about 2.5 cm tall, they can grow to 5 cm tall. Aiptasia pallida has a long thin column with nearly 100 tentacles in narrow rings around the oral disc. Tentacles are both long and easily visible as well as shorter. These tentacles alternate long and short around the oral disc, which is usually about 1 cm wide (Kaplan, 1982). (Kaplan, 1982; Stephenson and Stephenson, 1952)

  • Range length
    5 (high) cm
    1.97 (high) in
  • Average length
    2.5 cm
    0.98 in

Development

Because Aiptasia pallida is in the class Anthozoa, it only has a polyp stage. Polyps give rise to polyps, and there is no alternation of generations. It is likely that Aiptasia pallida produces plaular larvae, as do other anemones, but this has not been documented to date. (Schechter, 1959)

Reproduction

Pale anemones reproduce asexually by pedal laceration. Either the pedal disc puts out lobes that are constricted off or pieces of the disc adhere and are torn off as the anemone moves about. The torn edges unite, new tentacles and septa (thin dividing membranes) develop along lines of closure, and new septa relate themselves to the old septa left in the torn pieces (Hyman, 1940). This method of reproduction forms clones of genetically similar individuals and small groups of adjacent animals linked genetically to a single anemone (Jennison, 1983). In addition, starvation initiates asexual reproduction by pedal laceration (Clayton and Lasker, 1985). Sexual reproduction has not been described for the species. (Clayton and Lasker, 1985; Hyman, 1940; Jennison, 1983)

  • Key Reproductive Features
  • asexual

Aiptasia pallida reproduces aesexually and there is no parental investment.

  • Parental Investment
  • no parental involvement

Behavior

Aiptasia pallida swim by ciliary action in spirals (Lenhoff and Muscatine, 1974). Also, this anemone can crawl on its side, progressing at about 4 cm per hour. To do this, the pedal disc is pushed forward by contraction of circular muscles, the trunk shortened by contraction of longitudinal septal muscles, and the oral disc pulled along after (Kaestner, 1967). (Kaestner, 1967; Muscatine and Lenhoff, 1974)

Communication and Perception

In Anthozoans, specialized sensory organs are absent and nerves are arranged in nerve nets. Most nerve cells allow impulses to travel in either direction. Hairlike projections on individual cells are mechanoreceptors and possible chemoreceptors. Some Anthozoans show a sensitivity to light. (Brusca and Brusca, 2003)

Food Habits

Aiptasia pallida contain zooxanthellae, or symbiotic dinoflagellate algae, which produce oxygen and fix carbon by photosynthesis. Much of the carbon fixed is realeased to the anemone, aiding in its energy needs. Pale anemones also feed on zooplankton; this feeding can affect zooxanthellal photosynthetic oxygen production by either changing the number of zooxanthellae within the host anemone or by changing the individual zooxanthellal production. (Clayton and Lasker, 1984)

Ecosystem Roles

Mutualist Species
  • zooxanthellae (symbiotic algae)

Other Comments

Pale anemones have been found to contain a kind of neurotoxin which has hemolytic effects on red blood cells and affects ionic conductance in crayfish giant nerve fibers. Another neurotoxin found in A. pallida can cause leg autotomy and death in fiddler crabs. (Muscatine and Lenhoff, 1974)

Contributors

Renee Sherman Mulcrone (editor).

Caitlin Vaughn (author), Hood College, Maureen Foley (editor), Hood College.

Glossary

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

asexual

reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

coastal

the nearshore aquatic habitats near a coast, or shoreline.

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

colonial growth

animals that grow in groups of the same species, often refers to animals which are not mobile, such as corals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.

native range

the area in which the animal is naturally found, the region in which it is endemic.

photic/bioluminescent

generates and uses light to communicate

planktivore

an animal that mainly eats plankton

radial symmetry

a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).

reef

structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

sessile

non-motile; permanently attached at the base.

Attached to substratum and moving little or not at all. Synapomorphy of the Anthozoa

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

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

Clayton, W., H. Lasker. 1984. Host Feeding Regime and Zooxanthellal Photosynthesis in the Anemone *Aiptasia pallida*. The Biological Bulletin, 167: 590-600.

Clayton, W., H. Lasker. 1985. Individual Population Growth in the Asexually Reproducing Anemone *Aiptasia pallida*. Journal of Experimental Marine Biology and Ecology, 90: 249-258.

Colin, P. 1978. Caribbean Reef Invertebrates and Plants: A Field Guide to the Invertebrates and Plants Occurring on Coral Reefs of the Caribbean, the Bahamas, and Florida. Neptune City, New Jersey: T.H.F. Publications, Ltd..

Hyman, L. 1940. The Invertebrates:Protozoa through Ctenophora. New York: McGraw-Hill Book Company.

Jennison, B. 1983. Reproductive Biology of Three Species of Sea Anemone from the Central Atlantic Coast of Florida. Florida Scientist, 46: 179-186.

Kaestner, A. 1967. Invertebrate Zoology, Vol. I. New York: Interscience Publishers.

Kaplan, E. 1982. A Field Guide to Coral Reefs of the Caribbean and Florida Including the Bahamas. Boston, Massachusetts: Houghton-Mifflin Company.

Muscatine, L., H. Lenhoff. 1974. Coelenterate Biology: Reviews and New Perspectives. New York: Academic Press.

Schechter, V. 1959. Invertebrate Zoology. New Jersey: Prentice-Hall, Inc..

Stephenson, T., A. Stephenson. 1952. Life Between the Tide-Marks in North America. Journal of Ecology, 40: 33-35.

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