Goniastrea favulus
Uncommon stony coral with near threatened conservation status.
Goniastrea favulus, called the lesser star coral, is a stony coral belonging to the family Merulinidae. It lives in shallow waters across the Indo-Pacific and is not common; the IUCN lists it as "near threatened".
The coral forms massive, boulder-like colonies that are usually greenish or brownish. Its polyps sit either in groups inside a shared corallite wall or in meandroid valleys. The corallite walls are thin, the septa have large paliform lobes, and there is a small central columella.
This species is found from northern Madagascar and East Africa to the Maldives, Southeast Asia, Japan, Australia, and various Pacific islands. It occurs in intertidal and subtidal zones on fore and hind reef slopes and in lagoons, generally no deeper than 15 meters (50 feet), and is seldom abundant.
Goniastrea favulus is zooxanthellate, hosting symbiotic dinoflagellates in its tissues that provide it with photosynthesis products during the day. At night, its polyps extend their tentacles to catch zooplankton. Colonies are simultaneous hermaphrodites that spawn once a year in a synchronized event, with all nearby colonies releasing gametes at roughly the same time. Sperm is ejected in a jet, while eggs are negatively buoyant, coated in mucus, and stick to the colony. Most eggs are cross-fertilized, but many are self-fertilized. This differs from the related Goniastrea aspera and most other broadcast spawners, which release both eggs and sperm in buoyant bundles that float to the surface for fertilization.
Quick Facts
- Taxon
- Goniastrea favulus
Facts from the source article.
Lore & Background
Colonies of Goniastrea favulus usually form greenish or brownish massive boulder-like structures. The polyps are either arranged in groups within a common corallite wall, or are in meandroid valleys. The walls of the corallites are thin, the septa bear large paliform lobes and there is a small central collumella.
This species is native to the Indo-Pacific region, with a range extending from northern Madagascar and the eastern coast of Africa to the Maldive Islands, southeastern Asia, Japan, Australia and island groups in the Pacific Ocean. It is found in the intertidal and subtidal zones on fore and hind reef slopes, and in lagoons, generally uncommon and seldom deeper than 15 metres.
Goniastrea favulus is a zooxanthellate species, containing symbiotic dinoflagellates that provide products of photosynthesis during the day. At night, the polyps expand and extend tentacles to catch zooplankton. Colonies are simultaneous hermaphrodites and spawn once a year in a synchronized event. The sperm is released in a jet, while eggs are negatively buoyant, surrounded by mucus, and adhere to the colony. Although a majority of eggs are cross-fertilised, a large number are self-fertilised, contrasting with closely related Goniastrea aspera and most other broadcast spawners.
Reader's Guide
Goniastrea favulus is notable for its uncommon occurrence and near threatened conservation status, as assessed by the International Union for Conservation of Nature. Its distribution across the Indo-Pacific, from eastern Africa to Japan and Pacific islands, highlights its broad but sparse presence in shallow reef environments. Ecologically, it is a zooxanthellate coral, relying on symbiotic dinoflagellates for daytime energy and supplementing its diet by catching zooplankton at night. Its reproductive strategy is distinctive among broadcast spawners: while most release buoyant egg-sperm bundles that float to the surface, Goniastrea favulus releases sperm in a jet and retains negatively buoyant, mucus-covered eggs on the colony. This allows a large number of self-fertilised eggs alongside cross-fertilised ones, a contrast to the closely related Goniastrea aspera. The species' thin corallite walls, large paliform lobes, and small central collumella are key morphological features. Its presence in intertidal and subtidal zones, including lagoons and reef slopes, underscores its adaptability to varied shallow-water habitats, though it seldom exceeds 15 metres in depth.
Did You Know?
- Goniastrea favulus is also known as the lesser star coral.
- Unlike most broadcast spawners, its eggs are negatively buoyant and adhere to the colony, and a large number are self-fertilised.
Frequently Asked Questions
What is Goniastrea favulus?
Goniastrea favulus, commonly called the lesser star coral, is a stony coral species in the family Merulinidae. It builds large, boulder-shaped colonies and is considered uncommon throughout its Indo-Pacific range.
Where does Goniastrea favulus live?
This coral occupies intertidal and subtidal zones on fore and hind reef slopes as well as lagoon settings, generally at depths of 15 metres or less. Its distribution spans from northern Madagascar and East Africa eastward through the Maldives, Southeast Asia, and up to Japan.
What does Goniastrea favulus look like?
The colonies are massive and boulder-like, typically greenish or brownish in colour. Polyps cluster either within shared corallite walls or line meandroid valleys, featuring thin walls, large paliform lobes on the septa, and a small central columella.
How does Goniastrea favulus reproduce?
Each colony is a simultaneous hermaphrodite, carrying both male and female reproductive tissue at the same time. The species releases its gametes during a single annual spawning event.
What is the conservation status of Goniastrea favulus?
The IUCN classifies Goniastrea favulus as near threatened, reflecting its uncommon occurrence in the wild. Its shallow depth range and specific reef-habitat requirements make it particularly vulnerable to environmental shifts across the Indo-Pacific.
More in Brain and Merulinid Corals 1-24
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