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Retracted Phyllangia americana polyps surround by pink coralline algae, barnacles and limpets. Photo courtesy of the Southeastern Regional Taxonomic Center (SERTC), South Carolina Department of Natural Resources.

The hidden cup coral, Phyllangia americana, with polyps retracted. Photo by L. Holly Sweat, Smithsonian Marine Station at Fort Pierce.

Species Name: Phyllangia americana Milne-Edwards & Haime, 1849
Common Name: Hidden Cup Coral
Synonymy: Phyllangia fuegoensis Squires, 1963

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Cnidaria Anthozoa Scleractinia Caryophylliidae Phyllangia

    Please refer to the accompanying glossary for definitions of the descriptive terms used in this report.

    Species Description

    Colonies of the hidden cup coral, Phyllangia americana, form small groups of polyps that encrust hard surfaces (Humann 1993). The corallites are circular with deep central pits. The rims are marked with six primary and six secondary septa. Polyps of P. americana range in color from brown to yellowish brown to reddish brown.

    Potentially Misidentified Species

    The hidden cup coral is similar in appearance to the speckled cup coral, Rhizosmilia maculata. However, polyps of R. maculata have a distinct speckled pattern and twelve large septa instead of the six seen in P. americana (Humann 1993).


    Habitat & Regional Occurence

    The range of P. americana extends from South Carolina (Gleason et al. 2012) to Florida, around the Gulf of Mexico (Cairns 1978), in the Bahamas and throughout the Caribbean (Humann 1993). Polyps encrust the undersides of subtidal rocks, ledges and cave ceilings down to about 50 meters (Cairns 2009). Sponges, algae and other organisms often overgrow the surrounding substrate, making only the individual polyps visible.



    P. americana is an ahermatypic coral, meaning that the species is solitary and does not form large reefs like many other stony corals (e.g. Cairns 1978). Individual coral colonies are generally small, with the diameter of polyps measuring about 1.5 cm (Humann 1993).


    The abundance of P. americana in the IRL remains undocumented. However, average densities of the hidden cup coral on natural and artificial reefs around Tampa Bay, FL have been recorded at approximately 26 colonies per square meter (Rice & Hunter 1992).


    No information is available at this time


    No information is available at this time


    No information is available at this time


    Cairns SD. 1978. A checklist of the ahermatypic scleractinia of the Gulf of Mexico, with the description of a new species. Gulf Res. Rep. 6: 9-15.

    Cairns SD. 2009. Phylogenetic list of the 711 valid recent azooxanthellate scleractinian species with their junior synonyms and depth ranges. 28 pp. In: Cold-Water Corals: The Biology and Geology of Deep-Sea Coral Habitats. Cambridge University Press, Cambridge. Online:

    Gleason DF, Harvey AW & SP Vives. 2012. A guide to the benthic invertebrates and cryptic fishes of Gray’s Reef. Georgia Southern Univ. Online:

    Humann P. 1993. Reef Coral Identification: Florida, Caribbean and Bahamas. New World Publications, Inc. Jacksonville, FL. 239 pp.

    Rice SA & CL Hunter. 1992. Effects of suspended sediment and burial on scleractinian corals from west central Florida patch reefs. Bull. Mar. Sci. 51: 429-442.

Page by LH Sweat
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Page last updated: 28 December 2012

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