seen? These corals can form delicate colonies that resemble
miniature underwater forests. They are always a delight to encounter.
Sometimes seen on many of our Southern shores, larger colonies are
more commonly seen on undisturbed and remote reefs. The genus Acropora
has the largest number of species of all the hard corals. The scientific
name is usually pronounced as 'ah-crop-or-ah'.
Features: Colonies seen
usually 15-20cm, but on undisturbed shores can be 50cm or larger.
Many grow into branching forms that give rise to common names like
'staghorn coral'. For some, the entire colony often has a flat top
so they are sometimes also called 'table-top' or 'table coral'. Others
appear bushy. Branches are generally cylindrical with corallites appearing
all around the branch.
Corallite tiny (0.5cm) smooth cups or tubes. Acropora corals have
a distinctive corallite, usually at the tip of the branch, that is
larger than the other corallites. This is called an axial corallite.
New corallites (called secondary or radial corallites) bud off along
the sides while the axial corallite continues to grow upwards on the
tip of the branch. The axial corallite lacks zooxanthellae but grows
rapidly as it is fed by other areas of the colony. The tips are often
white or brightly coloured.
Polyps tiny (0.2-0.5cm), with long tapering tentacles. When fully
extended, the colony can appear 'furry'.
Sometimes mistaken for branching
There are probably several different species on these pages. It's
hard to distinguish them without close examination of small features.
On this website, they are grouped by large external features for convenience
As a group, acropora corals are adaptable and found in a wide range
of habitats from murky waters to wave-pounded areas and some can survive
regular exposure at low tide. These protect themselves with a thick
mucus coat and UV-absorbing substances. They come in a wide variety
Some acropora corals are rather delicate and will shatter if they
are knocked against. So please do not touch them, in fact, we should
not touch any living hard corals.
Role in the habitat: Acropora
corals are among the important building blocks of a reef. Together
with Montipora species, also members of the Family Acroporidae,
acropora corals account for one-third of reef-building coral species.
Acropora corals include some of the fastest growing hard corals. Their
branching forms provide shelter to a wide variety of animals, from
small fishes to tiny clams, small crabs to shrimps.
Human uses: Acropora corals are
popular in the live aquarium trade and wild colonies are often taken
from the natural reefs to supply this demand. Efforts to breed and
raise acropora corals have been successful and it is hoped this supply
will reduce collection from the wild. Although captive bred acropora
corals are healthier and easier to care for than wild collected specimens,
captive bred corals are more expensive.
and threats: Some of our Acropora corals are listed as
threatened on the IUCN global listing.
Like other creatures of the intertidal zone, they are affected by
human activities such as reclamation and pollution. Trampling by careless
visitors, and over-collection by hobbyists also have an impact on
Some acropora coral form table-like colonies.
Raffles Lighthouse, Jun 07
Corallites with tentacles
Sisters Island, Dec 05
With the tentacles extended,
the colony can appear 'furry'.
Pulau Semakau, Apr 08
Producing mucus to protect themselves.
Pulau Semakau, Mar 05
Sisters Island, May 08
species recorded for Singapore
Huang, Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec 2009.
An inventory of zooxanthellate sclerectinian corals in Singapore
including 33 new records **the species found on many shores in
*Groups based on in Veron, Jen. 2000. Corals of the World.
in red are those listed as threatened
on the IUCN global list.
corals seen awaiting identification
are difficult to positively identify without close examination
with a microscope. On this website,
they are grouped by external features for convenience of display.
6: Large staghorn-like
Acropora muricata=Acropora formosa (Staghorn coral) (Near
Group 7: Large encrusting or horizontally branching species
with rasp-like radial corallites
Acropora intermedia=Acropora nobilis
Acropora palmerae (Vulnerable)
Group 8: Large horizontally branching with upturned branch
Acropora acuminata (Vulnerable)
Acropora donei (Vulnerable)
Group 9: Interlocking basal branches and sharp edged radial
Acropora divaricata (Near Threatened)
Acropora solitaryensis (Vulnerable)
Group 10: Interlocking basal branches and rounded radial
Acropora glauca (Near Threatened)
Group 11: Conspicuous secondary branches and smooth edged
Acropora austera (Near Threatened)
Acropora florida (Near Threatened)
Acropora lutkeni (Near Threatened)
Group 12: Small, stag-horn like
Group 14: Middle-sized branches and irregular radial corallites
Acropora horrida (Vulnerable)
Group 19: Tables with fine horizontal branches
Acropora hyacinthus (Near Threatened)
Acropora spicifera (Vulnerable)
Group 21: Digitate clumps with finger-like branches
Acropora humilis (Near Threatened)
Group 22: Digitate plates with small branchlets
Acropora dendrum (Vulnerable)
Acropora digitifera** (Near Threatened)
Group 24: Digitate clumps with spiny corallites
Acropora polystoma (Vulnerable)
Group 26: Branching with scale-like radial corallites
Acropora aspera (Vulnerable)
Acropora nana (Near Threatened)
Group 27: Corymbose clumps with short thin branchlets and
appressed radial corallites
Group 28: Corymbose clumps with diverging horizontal branches
and small radial corallites
Acropora aculeus** (Vulnerable)
Group 29: Corymbose clumps within thin branchlets and radial
corallites with flaring lips
Acropora selago (Near Threatened)
Acropora tenuis (Near Threatened)
Group 30: Corymbose plates with short compact branchlets and
variable radial corallites
Acropora anthocercis (Vulnerable)
Acropora willisae (Vulnerable)
Group 31: Corymbose bushes or plates with elongate tubular axial
Acropora granulosa (Near Threatened)
Group 32: Corymbose bushes with conspicuous rounded corallites
Acropora loripes (Near Threatened)
Acropora verweyi (Vulnerable)
Group 33: Bushes with irregular smooth edged radial corallites
Acropora secale (Near Threatened)
Group 34: Bushes with sharp edged radial corallites
Acropora nasuta (Near Threatened)
Group 35: Bushes with appressed radial corallites
Group 38: Bottlebrush colonies
- Danwei Huang,
Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec 2009. An
inventory of zooxanthellate sclerectinian corals in Singapore
including 33 new records (pdf). Raffles Bulletin of Zoology
Supplement No. 22: 69-80.
- Veron, Jen.
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Australian Institute of Marine Science, Australia. 3 volumes.
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M., 1998. A
Guide to the Coral Reef Life of Singapore. Singapore Science
Centre. 128 pages.
Harry and Daniel Knop. 2005. Corals:
Indo-Pacific Field Guide
IKAN-Unterwasserachiv, Frankfurt. 305 pp.
Eric H. 2001. Aquarium
Corals: Selection, Husbandry and Natural History
T.F. H Publications. 464 pp
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.