Mushroom Coral (Plate Coral, Disc Coral)
Phylum: Cnidaria, Class: Anthozoa, Order: Scleractinia, Family: Fungiidae, Genus: Fungia, Species: scutaria · Fungiidae (Mushroom Coral family) · Cnidarian Skeleton (Solid Scleractinian Coral). Shape: Disc-like or circular with radial symmetry.
Species
Fungia scutaria (Confidence: 85% - identifying as a Fungia species skeleton)
Shell Type
Cnidarian Skeleton (Solid Scleractinian Coral). Shape: Disc-like or circular with radial symmetry.
Family
Fungiidae (Mushroom Coral family)
Size
Approximately 4-5 inches (10-13 cm) in diameter. Typical range for matured individuals of this species is 2-8 inches.
Color & Pattern
Naturally bleached white to off-white/beige skeleton. In life, these specimens are colorful (browns, greens, or purples), but as a 'shell' collector item, only the calcium carbonate structure remains. It features a stunning radial pattern of septa (blade-like ridges) extending from the central fossa.
Rarity
Common (Beachcombing for fragments is common, but large, intact whole skeletons like this are considered Uncommon finds on most tourist beaches).
Habitat
Found in marine environments on shallow tropical coral reefs. Unlike most corals, they are usually free-living and unattached to the substrate, often resting on sandy or rubble bottoms between reef patches.
Geographic Range
Indo-Pacific region, extending from the Red Sea and East Africa across the Pacific to Hawaii and the Line Islands.
Description
A beautiful, circular stony coral skeleton characterized by thin, sharp, radiating ridges called septa. The structure resembles the underside of a mushroom cap. The center features an elongated mouth-pit (fossa). The edges are slightly undulating, and the texture is brittle yet dense, composed of aragonite.
Key Features
Single-polyp organism (unlike colonial corals), circular or oval shape, radiating septa of varying heights, and a central indentation where the polyp's mouth once resided.
Collector Value
Modest value ($10-$30 USD). While aesthetically pleasing and popular for coastal decor, they are common in the trade. Value increases with size, perfect symmetry, and lack of chipped septa.
Condition Notes
Good to Fine condition. The septa appear mostly intact, though there is minor edge chipping. Some natural sediment and slight discoloration are visible in the central crevices. It lacks the fleshy polyp, indicating it is a dead-collected skeleton.
Interesting Facts
Mushroom corals are unique because they are 'mobile' corals; the living polyp can use its tentacles and inflate its body to move slowly across the sand or flip itself over if it gets turned upside down. They are also among the largest single-polyp corals in the ocean.
Ecological Role
Primary reef-builders that contribute to the calcium carbonate structure of reefs. They provide habitat for small reef creatures. Note: Collection of live coral is strictly regulated or illegal in many regions under CITES Appendix II; only 'dead-washed' beach specimens should be collected.
Similar Species
Lithophyllon (which is usually encrusting) and Cycloseris (which is smaller and more perfectly circular). Fungia is distinguished by its larger size and the specific arrangement of the septal teeth.
Beach Finding Tips
Look in the 'wrack line' after storms on tropical Indo-Pacific islands. They are often found washed up on beaches near healthy reef systems, especially in areas with sandy lagoons.