Animal Diversity Web

Geographic Range

Bartholomea annulata is typically found in the Caribbean, the Gulf of Mexico and the Western Atlantic. They range from coastal Texas eastward to the Atlantic coast of Florida. Bermuda marks the northern-most extent of their range. The species also extends south to the Northern Coast of South America. (Zeiller, 1974)

• Biogeographic Regions
• atlantic ocean
  • native

Habitat

This anemone is often found under ledges, but more commonly found as a sand-pocket dweller among Halimeda algal populations. It generally attaches in holes and crevices in coral reefs, rocky areas, and other solid substrate. It is commonly found at depths ranging from one to forty meters but may occur deeper. (Jennison, 1981; Zeiller, 1974)

• Habitat Regions
• tropical
• saltwater or marine

• Aquatic Biomes
• benthic
• reef
• coastal

• Range depth

  1 to 40 m

  3.28 to 131.23 ft

Physical Description

The corkscrew anemone can be more than 51 mm high and 38 mm across its basal disk. The pedal disc is located on the bottom of this anemone and is used to attach to solid substrate. The base and column often project from a crevice and may remain hidden from view. While the base remains firmly attached to a solid substrate a large mass of tentacles floats above. This anemone possesses an abundance of dense tentacles that may grow as long as 12.5 cm. Its 200 tentacles are long, delicate and covered with a continuous spiral band of white nematocysts. The mouth is located in the center of this large mass of tentacles. Colors of the B. annulata range from an almost transparent pale brown to a dark brown. Color is produced by zooxanthellae in the tissues of the anemone. (Colin, 1978; Meinkoth, 1981; Zeiller, 1974)

• Other Physical Features
• ectothermic
• heterothermic
• radial symmetry

Development

At about one to two weeks of age new anemones develop a mouth and small tentacles. They then begin to feed on microscopic food particles in the water. (Jennison, 1981)

Reproduction

Bartholomea annulata exhibits a biannual reproductive cycle. It conducts asexual reproduction through the use of pedal laceration. In this process a small bud of tissue is formed on the margin of the anemone’s pedal disk, it breaks off to form a new anemone. This anemone may also reproduce sexually. It is oviparous and produces planktonic larvae. The anemone broadcasts its eggs and larvae are widely distributed by water currents. It is argued that this method of reproduction is superior to asexual reproduction because it allows the organism to widely disperse its young while it also has a high cost due to the high risk of mortality. (Jennison, 1981; Lin, et al., 2001)

• Key Reproductive Features
• seasonal breeding
• sexual
• asexual
• fertilization
  • external
• oviparous

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning

Lifespan/Longevity

The lifespan of anemones is not accurately known since it is difficult to maintain them in aquaria long enough to ascertain lifespan with any certainty. Estimates range from several years to decades.

Behavior

Bartholomea annulata is a sessile organism that attaches to hard substrate.

• Key Behaviors
• sessile

Communication and Perception

Since little work has been done on the B. annulata little is known about how it communicates with its fellow anemones. However, 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)

When touched by a larger foreign object this anemone will retract quickly into the hole or crevice where it is attached (Lemay 2002, personal observation). (Brusca and Brusca, 2003)

• Communication Channels
• tactile
• chemical

• Perception Channels
• tactile
• chemical

Food Habits

Smaller Bartholomea annulata feed on zooplankton, while larger specimens feed on both zooplankton and may even take in macroscopic prey. They use long tentacles to paralyze prey with toxin injected by the nematocysts found in rings on tentacles. The food is then carried down the tentacles toward the mouth that is found in the center of the dense mass of tentacles. (Zeiller, 1974)

• Primary Diet
• carnivore
  • eats non-insect arthropods
• planktivore

• Animal Foods
• aquatic crustaceans
• zooplankton

Predation

Anti-predator adaptations included toxin-injecting nematocysts and the ability to shrink away and withdraw quickly from disturbance. Sea spiders prey on these anemones causing excess mucus production and difficulty attaching to substrate. Predation by sea spiders often results in death. (Mercier and Hamel, 1994)

• Known Predators

  • sea stars (Asteridae)
  • nudibranchs (Nudibranchia)
  • sea spiders (Pigrogromitus timsanus)

Ecosystem Roles

The Bartholomea annulata are members in a number of symbiotic relationships. They host zooxanthellae, Symbiodinium sp. dinflagellate algae that grow within the cells of the anemone aiding in biological functions and providing color.

They are also part of an association with a number of crustacean species. Many small crustaceans such as the Periclimenes yucatanicus and the Alpheus armatus receive protection within the tentacles of the anemone and also may perform cleaning functions for the anemone. (Colin, 1978)

• Ecosystem Impact
• creates habitat

Economic Importance for Humans: Positive

Since the Bartholomea annulata uses the method of asexual reproduction known as pedal laceration it creates genetically identical clones. This method of reproduction allows researcher quickly and easily produce an abundance of genetically identical subjects. This can be extremely helpful to researchers when genetic variation is an unwanted variable in an experiment. (Jennison, 1981)

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

None, although nematocysts do produce toxins, they are not produced in large enough quantities to be harmful to humans.

Contributors

Renee Sherman Mulcrone (editor).

Julie Lemay (author), Hood College, Maureen Foley (editor), Hood College.

References

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

Colin, D. 1978. Caribbean Reef Invertebrates and Plants. Neptune City, NJ: T.F.H. Publications, Inc..

Jennison, B. 1981. Reproduction in three species of sea anemones from Key West, Florida. Canadian Journal of Zoology, 59(9): 1708-1719.

Lin, M., C. Chen, L. Fang. 2001. Distribution and Sexual Reproduction of a Seagrass-bed-inhibiting Actiniarian, *Phymanthus strandesi*, at Hsiao-Liuchiu, Taiwan. Zoological Studies, 40 (3): 254-261.

Meinkoth, N. 1981. National Audubon Society Field Guide to North American Seashore Creatures. New York: Alfred A. Knopf.

Mercier, A., J. Hamel. 1994. Deleterious effects of a pycnogonid on the sea anemone *Bartholomea annulata*. Canadian Journal of Zoology, 72(7): 1362-1364.

Zeiller, W. 1974. Tropical Marine Invertebrates of South Florida and the Bahama Islands. New York: Wiley Interscience Publication.