Wednesday, May 24, 2017

Heliopora


Under construction

Heliopora (Order Helioporacea)

Welcome to the Heliopora 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 verify what you saw underwater. Then click on the following link for further comparison with a similar genus: Millepora.

The genus Heliopora is a member of the coelenterate class Anthozoa, as are the scleractinians described in the Coral Finder and Coral Hub.  But unlike the scleractinians which are members of the subclass Hexacorallia, Heliopora is a member of the subclass Octocorallia (also known as the Alcyonarians).  This group of corals have polyps encircled by 8 tentacles that are bordered by rows of delicate pinnules.  For more information, check out the Octocorallia page on Coral Hub.  There is only one species within the Heliopora, but the fossil record indicates that this species and its close relatives have been around for over 100 million years!

Vital Statistics

  • 1 species
  • Coral Finder p. 2c, 3c, 29
  • COTW – Vol 3 p. 144-145

Distribution

Found in the Indo-Pacific.

ID Tips

Heliopora colonies may form thick branches, columns or convoluted plates, and often develop into large stands reaching several meters in diameter.  Unlike other members of the Octocorallia, which do not form a thick, solid skeleton, Heliopora forms an aragonite skeleton similar to the scleractinians.  Zooxanthellae are also found within the tissues.

In contrast to the large colonies, the white polyps are tiny (1mm) and immersed.  The polyps bear a ring of eight delicate tentacles.  The colony surface is smooth, brown in colour, and covered in a fine layer of delicate hairs.  Underneath this layer of brown tissue, the skeleton is blue in colour, hence the common name ‘Blue Coral’.  Searching the colony for broken or chipped branches allow the hidden blue colouration to be identified.

Similar Genera

The Coral Finder lists Heliopora in one key group with other non-scleractinians.  Millepora may be a possible source of confusion, but the two genera can be differentiated by the blue colour of the skeleton that is distinctive of HelioporaMillepora does not have a blue skeleton, and the colony surface is hairier than that of Heliopora.

Heliopora

Similar genus: Millepora

Ecology

Taxonomic Changes

Learning Resources

Coral Hub

  • Octocorallia page

Links

Suggested Reading – Identification Tools

  • Fabricus, K. & Alderslade, P. (2001).  Soft Corals and Sea Fans.  Melbourne: Australian Institute of Marine Science.
  • Veron, J. E. N. (2000). Corals of the World. Melbourne: Australian Institute of Marine Science.

Suggested Reading – Other Topics

  • Weingarten, R. A. (1992). Notes on the reproduction and development of Heliopora caerulea. FAMA 1/92.