The order Corallimorpharia comprises a group of marine cnidarians commonly known as corallimorphs or false corals, organisms that superficially resemble stony corals (Scleractinia) but lack a calcareous skeleton. This absence of a rigid skeleton gives them greater flexibility and allows them to adapt to a wide range of marine habitats. False corals exhibit radial symmetry and a well-developed oral disc surrounded by tentacles, which they use for prey capture and territorial defense. Their name derives from the Latin corallium (coral) and the Greek morphe (form), referring to their morphological similarity to true corals. They are distributed in tropical and subtropical oceans worldwide, occurring both in shallow reef-associated waters and deeper environments. Approximately 50 species have been described within this order.
Morphologically, false corals display a polyp-like body with a base that allows them to attach to hard substrates, such as rocks and dead coral skeletons. Their oral disc, often brightly colored with variable patterns, can range from a few centimeters in diameter to over 30 cm in giant species such as Amplexidiscus fenestrafer. Tentacles may be short and warty or long and filamentous, depending on the species, and are equipped with stinging cnidocytes to immobilize prey and deter predators. Unlike stony corals, they lack calcified septa, giving them a soft consistency similar to that of sea anemones (Actiniaria).
Ecologically, false corals are opportunistic predators but can also obtain energy through symbiosis with photosynthetic algae. Many species host zooxanthellae in their tissues, allowing them to supplement their diet with photosynthetic products, particularly in clear, shallow waters. Their heterotrophic feeding consists of capturing plankton, small invertebrates, and particulate organic matter, which they transport to their mouth using their tentacles. Larger species are capable of capturing small fish thanks to their potent stinging ability and the secretion of adhesive mucus.
The sub-classification of this order includes four main families. Tropical corallimorphs (family Corallimorphidae) include vividly colored species common in Indo-Pacific reefs, such as Corallimorphus profundus. Giant corallimorphs (family Discosomatidae) comprise large, disc-shaped species, including Amplexidiscus and Discosoma, which are also popular in aquaria. Cold- and deep-water corallimorphs (family Ricordeidae) include species adapted to low-light environments, such as Ricordea florida. The fourth family, Sideractinidae, contains only two known species. This diversity of forms and adaptations has allowed corallimorphs to occupy a wide range of ecological niches, functioning both as predators and as secondary habitat builders in marine ecosystems.
From an evolutionary perspective, false corals are considered a key group for understanding the transition between sea anemones and stony corals, due to their structural similarities and divergence in skeletal production. Furthermore, some studies suggest they may play an important role in reef resilience, as they tend to colonize degraded areas and help stabilize the substrate. Their morphological and ecological diversity, along with their adaptive capacity, makes them a particularly interesting group for research in marine biology and conservation.
