Noble coral

Noble coral
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
Phylum:	Cnidaria
Subphylum:	Medusozoa
Class:	Hydrozoa
Subclass:	Hydroidolina
Order:	Anthoathecata
Suborder:	Filifera
Family:	Stylasteridae
Genus:	Stylaster
Species:	S. nobilis
Binomial name
Stylaster nobilis Stechow, 1921

The noble coral (Stylaster nobilis) is a branching colonial hydroid in the family Stylasteridae.^[1]

Description

Growth rings are visible in this broken specimen. The white core is the original growth

Noble corals are pink or orange and tree-like with paler tips to the colony's branches. The calcareous colonies may grow to over 25cm in total height, while individual polyps are 0.1cm in diameter.^[2] There is no free medusa stage.

The polyps project from star-shaped cavities in the rigid calcareous skeleton. Growth occurs at the tips and on the outside surface, which gradually thickens and which may show concentric rings in section.

Colour and shape variation

• 
  Two colour morphs at Oudekraal, on the Cape Peninsula
• 
  Occasionally S. nobilis will develop a more encrusting structure
• 
  Specimens from about 35m depth in the Tsitsikamma Marine Protected Area
• 
  A densely packed structure is also possible
• 
  A stocky morph can be found in a few places
• 
  The colouration may occasionally be mottled
• 
  In some areas there is significantly less branching
• 
  In some cases there may be no branching at all

Distribution

This colonial animal is found only off the South African coast from the Atlantic Coast of the Cape Peninsula to Port Elizabeth in 5-100m of water. It is endemic to this region.^[2]

Ecology

Noble corals feed on plankton and resemble hard corals. They occur in cool temperate waters usually in caves and under overhangs. They are very slow-growing: large colonies may be over 100 years old. A permit is required to collect these animals. ^[2]

Synonyms

The following species are considered synonyms of Stylaster nobilis:^[1]

• Allopora explanata Kent, 1871
• Allopora nobilis Kent, 1871
• Allopora ochracea Qulech, 1884

References

1. http://marinespecies.org/aphia.php?p=taxdetails&id=210735 accessed 15 August 2013
2. Branch, G.M., Branch, M.L, Griffiths, C.L. and Beckley, L.E. 2010. Two Oceans: a guide to the marine life of southern Africa ISBN 978-1-77007-772-0