Acropora cervicornis   (Lamarck,  1816) (Hard Coral)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Cnidaria
Class: Hexacorallia
Order:Scleractinia
Family:Acroporidae

Image copyrights: Charles Sheppard or Anne Sheppard

Description
Color: Pale brown or tan with white axial corallites.

These corals commonly have tentacles in multiples of three, which is characteristic of all corals belonging to the subclass Zoantharia, also known as Hexacorallia (Encarta 1997). At night, the tiny fingerlike tentacles of the corals emerge. They pump themselves up with water and pop out like tiny stars all over a coral reef (Sargent 1991). The staghorn coral, Acropora cervicornis, grows into "antler-like branches" so the polyps are raised above the sand (McGregor 1974). Staghorn corals have nematocysts, which are stinging cells that are located on their tentacles. These stinging cells are necessary for a coral to obtain food (Sisson 1973).

Staghorn corals as well as many other corals have a very unique symbiotic relationship with algae, in particular the zooxanthellae. These microscopic plants live inside the bodies of all reef-building polyps aiding their growth in an uncertain way. Without these alga, corals grow at 1/10th of the speed and are unable to establish the framework that is necessary for the growth of a coral reef (McGregor 1974). Because the alga needs light for photosynthesis, they play an important role in where a coral can live. Carbon is passed by the alga to the coral increasing its energy, and the food caught by the coral may supply nitrogen and phosphorus for both organisms (Encarta 1997).

As in all corals, the Staghorn Coral reproduces both sexually and asexually. The very first stage of reproduction is a sexually-caused stage of reef-building. This occurs when existing polyps expel millions of spermatoza into the water. Some of these gametes are drawn into other polyps that are nearby; the eggs that are produced there are then fertilized and larva develop and float away to produce new polyps. The larva, called planula, are extremely small and bulb-shaped. They are constantly changing shape as they swim/drift (Sisson 1973). They have a mouth at the upper end, which is the wider end with cilia like hairs all over them that are constantly beating and help support them to the surface. The planula that survive predators while floating through the water settle on a suitable hard surface in warm water and attach themselves by spreading out into a disk (Sisson 1973). Once they land here, they begin to secrete a white starlike outer skeleton which permanently cements it to a spot and develop tentacles and grow into mature polyps. Once the first skeletons are built, the founders, or the sexually produced polyps, multiply by asexual methods. Acropora grow branches, which are also known as buds, that become the daughter polyps, which then bud more daughters (McGregor 1974).

Similar species: Acropora prolifera. Acropora formosa of the Indo-Pacific has the same growth-form but corallites have thicker walls and more rounded lips.


Synonym (s)

Common Name (s)
• Staghorn Coral (English)
Economic Importance and Threats
Importance:  Ecosystem balance
(Fish habitats, stabilization of coastlines and protection of biodiversity.)

Ecology
Habitat:  Reef Associated
Trophic Level:  Consumer
Prey:  Plankton
Predator:  Butterfly fishes (Chaetodon trifascialis and Chaetodon trifasciatus)
IUCN Status:  Critically Endangered

Biogeography


• Tamil Nadu, Krusadai Island INDIA
• Tamil Nadu, Shingle Island INDIA

Literature Source(s)
  • Myers, P; Espinosa, R; Parr, CS; Jones, T; Hammond, GS and Dewey, TA (2006) Animal diversity web Available at - http://animaldiversity.org.
  • Carpenter, KE; Abrar, M; Aeby, G; Aronson, RB; Banks, S et al. (2008) One third of reef building corals face elevated extinction risk from climate change and local impacts Science American Association for the Advancement of Science 321 125-126 Available at - http://sci.odu.edu/gmsa/about/Carpenter_corals_supplimental.pdf
  • Wafar, MVM and Wafar, S (2001) 101 questions on corals: Towards awareness National Institute of Oceanography, Goa and Administration of the U.T. of Lakshadweep 81 pp Available at - NIO, Goa
  • Sheppard, C Coralpedia v 1.0: A guide to Caribbean corals, octocorals and sponges Available at - http://coralpedia.bio.warwick.ac.uk/
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org
  • Pillai, CSG (1971) Composition of the coral fauna of the southeastern coast of India and the Laccadives Symposium of the zoological society of London 28 301-327 Available at - http://eprints.cmfri.org.in/6215/1/601.pdf

Page last updated on:2011-04-08

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