Hidden cup coral

Phyllangia americana

Family Caryophylliidae - corals

Colonial polyps forming singular, cup-like structures (corallites), sometimes joined at the bases or between cups with a calcium carbonite skeletal layer (the coenosteum); color light brown (sometimes yellowish brown to reddish brown) within and on upper corallites, lower corallites and coenosteum white; corallites circular, usually ridged on the outside, central pits deep; septa (radiating plates inside corallite) arranged with 6 primary plates, 6 smaller ones and smaller ones in between those; live polyp with clear warty tentacles; encrusting (grows on other structures), non-reef forming.
Similar Species
The speckled cup coral, Rhizosmilia maculata, has 12 large septa (6 in the hidden cup coral) and live polyps have a speckled pattern. The hidden cup coral's brown color helps distinguish it from other cup corals.
Gulf and bay, attaches to hard substrates, jetties, pilings, shell
Maximum Size
corallites up to 1.5 cm (1/2 in)
Other Common Names
Previous Scientific Names