Sunday, November 23, 2014

Astreopora


Astreopora (Acroporidae)

Welcome to the Astreopora genus landing page. In this section, you will find general information about this genus and tips on how to identify it. If you are looking to confirm an observation made with the Coral Finder, use the image browser below to identify a growth form similar to what you saw underwater. Then choose one of the following links for further information: massive, encrusting or vase & tiered.


Lacking the numerous species or intricate designs found in the related genera Acropora and Montipora, Astreopora provides some calm from the storm for someone wanting to practice  species level ID. Until recently Astreopora was  considered a quiet backwater in the family Acroporidae but some new branching species have recently been described from eastern Indonesia – see below.

Vital Statistics

  • 12 species
  • Coral Finder p. 10, 17, 18
  • COTW – Vol 1 p.434-447

Distribution

Widespread in the Indo-Pacific.

ID Tips

Growth form varies from massive mounds to encrusting or plates, vases and branches.  Astreopora can be found in a wide range of reef environments including shallow and turbid waters through to deeper reef areas where plating forms predominate.  Generally uncommon but may be locally abundant.

Depending on species corallites may be immersed or form cones with dark cavernous centres.  These cones may be irregular in size and height.  A key feature of this genus are the spinules that cover the corallite walls and inter-corallite surface and lack of obvious septocostae . The spinules provide a generally ragged appearance to the colony surface and may line up in rows. Septocostae are absent giving corallites an empty appearance when compared to genera of similar size and growth form – see below.

Spinules, small obscure septa and a porous skeleton are typical of the family Acroporidae.

Similar Genera

The Coral Finder lists Astreopora in three key groups with Turbinaria, Cyphastrea, and to a lesser degree Echinopora, being candidates for confusion.

Similar genera to massive forms of Astreopora (Coral Finder p10)

Massive forms of Astreopora can be confused with Cyphastrea but are easily separated by the bristle-like skeletal surface texture (coenosteum) typical of Astreopora. Cyphastrea may also have spinules on the corallite walls and colony surface but they appear more “beaded”. Cyphastrea is also easily distinguished by better developed septocostae.

Massive Astreopora

Similar genus: Cyphastrea

Similar genera to irregular encrusting forms of Astreopora (Coral Finder p17)

When comparing Astreopora and Turbinaria which can have similar cone-like corallites, look at the colony surface, which on Turbinaria looks much smoother in comparison. Septa are better developed in Turbinaria but may not be visible underwater.

Encrusting Astreopora (Coral Finder p17)

Similar genus: Turbinaria

Similar genera to thin plated, vase and tiered forms of Astreopora (Coral Finder p18)

When comparing Astreopora and Turbinaria which can have similar cone-like corallites, look at the colony surface, which on Turbinaria looks much smoother in comparison.

Vase and tier-like forms of Echinopora have spinules on the corallite walls and colony surface but they appear more “beaded”. This genus is also  easily distinguished by their better developed septocostae.

Vase and tiered forms of Astreopora

Similar genus: Turbinaria

Taxonomic Changes

Coral taxonomy is under a constant state of flux as new species are described, and old species are split or amalgamated.  Astreopora provides a classic example of how our knowledge is constantly evolving: sources such as COTW describe colonies as massive, laminar and encrusting in form, but recent surveys have found  new branching forms of Astreopora in eastern Indonesia (personal communication E. Turak).  Coral Hub will provide links and images of these findings as soon as they available!

Ecology

The porous skeleton of Astreopora is home to a variety of ploycheate worms that burrow into the calcium carbonate structure weakening it.

Learning Resources

Coral Hub

  • Acroporidae family page

Links

Suggested Reading – Identification Tools

  • Veron, J.E.N. (2000).  Corals of the World.  Australian Institute of Marine Science: Melbourne, Australia, 1382pp.
  • Veron, J.E.N. & Wallace, C.C.  (1984).  Scleractinia of Eastern Australia, Part 5 Family Acroporidae.  Australian Institute of Marine Science Monograph Series 6: 485pp.
  • Lamberts, A.E.  (1982).  The reef coral Astreopora (Anthozoa, Scleractinia, Astroceoniidae): a revision of the taxonomy and description of a new species.  Pacific Science, 36(1): 83-105pp.
  • Veron, J.E.N.  (1986).  Corals of Australia and the Indo-Pacific.  Angus & Robertson: Sydney, 644pp.

Suggested Reading – Other Topics