Is this a duncan?

[cook]

 

[deanos]

No, but a close relative: Turbinaria Peltata (Pagoda Cup). Does it look like this at times?

 

[cook]

Yes, how can you tell the difference?

 

[cristhiam]

no duncan IMO, look at this thread, their size and growth pattern are different, mine is a little bigger than a quarter coin. It looks like a pagoda or an encrosting goni. How about another picture of that colony.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1066160&perpage=25&pagenumber=1

 

[deanos]

Duncanopsammia polyps do not grow from a common base (a 'cup' in the case of Turbinaria sp.). New polyps sprout from the base of an older polyp.

http://whelk.aims.gov.au/coralsearch/html/101-200/Species pages/135.htm

 

[Duce]

Nope.....not Duncan....