Larger knob coral (Dipsastraea speciosa)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Cnidaria · Class: Hexacorallia · Order: Scleractinia · Family: Merulinidae · Genus: Dipsastraea.

Accepted name: Dipsastraea speciosa · Authority: (Dana, 1846) · Taxonomic status: accepted · AphiaID: 758219.

Synonyms and superseded combinations recorded for this taxon: Astraea (Fissicella) fragilis Dana, 1846; Astraea (Fissicella) pandanus Dana, 1846; Astraea (Fissicella) puteolina Dana, 1846; Astraea (Fissicella) speciosa Dana, 1846; Astraea fragilis Dana, 1846; Astraea pandanus Dana, 1846; Astraea puteolina Dana, 1846; Astraea rudis Reuss, 1848; Astraea speciosa Dana, 1846; Astrea (Favia) rudis Verrill, 1866; Astrea fragilis (Dana, 1846); Astrea pandanus (Dana, 1846); Astrea puteolina (Dana, 1846); Astrea rudis Verrill, 1866; Astrea speciosa (Dana, 1846); Favia clouei Haime & Milne Edwards, 1857; Favia fragilis (Dana, 1846); Favia pandanus (Dana, 1846); Favia puteolina (Dana, 1846); Favia rudis (Verrill, 1866); Favia speciosa (Dana, 1846); Favia speciosa var. crenulata Chevalier, 1971; Favia speciosa var. exserta Chevalier, 1971; Favia speciosa var. irregularis Chevalier, 1971; Favia speciosa var. palifera Chevalier, 1971.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=758219 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (SeaLifeBase)

Measured values published by SeaLifeBase for Dipsastraea speciosa. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Depth range: 2–25 m · Habitat zone: reef-associated.

SeaLifeBase notes: Depth range is based on occurrence. Minimum depth from Ref. 115203. Occur in all reef environments (Ref. 848), subtidal on rocks, rocky reefs, outer reef channel, back and foreslopes and in lagoons (Ref. 98471). Depending on water conditions, can be found encrusting in small colonies, or forming massive heads (Ref. 130769).

Source: SeaLifeBase species summary (SpecCode 46730) — https://www.sealifebase.se/summary/Dipsastraea-speciosa.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

1,152 georeferenced occurrence records for Dipsastraea speciosa are published through GBIF from 45 countries or marine areas. The map above plots 196 distinct locations from a sample of 1,152 records, omitting 51 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Japan (494); Australia (362); Réunion (59); Marshall Islands (31); Indonesia (21).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 8400775) — https://www.gbif.org/occurrence/search?taxon_key=8400775&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=758219 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Dipsastraea speciosa (Dana, 1846) as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 133210) — https://www.iucnredlist.org/species/133210/0; GBIF IUCN Red List category endpoint (taxonKey 8400775) — https://api.gbif.org/v1/species/8400775/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

Dipsastraea speciosa has rounded to very elongated corallites, with diameters of 10 to 15 mm. The corallites are separated by broad walls, with a distance of 3 to 6 mm between individual corallites. This species can be distinguished from the more common Dipsastraea pallida, with which it has often been confused, by its septa, which are fine, numerous, and regularly spaced. Both the septa and costae have fine, evenly spaced teeth.

Colonies of Dipsastraea speciosa are massive in their growth habit. The corallites are crowded together, subcircular, with calices up to 12 mm in diameter. Their coloration ranges, including pale grey, green or brown, usually with calices of contrasting color. Colonies of Dipsastraea speciosa tend to be massive.

It is a tropical coral found in all shallow, tropical reef environments in the Indian and Pacific Oceans. It can be found at depths ranging from 0 to 40m. It can be found in all reef environments, sub-tidal on rocks, rocky reefs, outer reef channels, black and fore-slopes and in lagoons. Dipsastraea speciosa prefers waters ranging from 23° to 29 °C but can tolerate temperatures slightly above and below.

Like most other corals, they contain photosynthetic algae, called zooxanthellae. Dipsastraea speciosa and the algae have a mutualistic relationship. The algae live within the coral polyps and use sunlight to make energy. The coral provides protection and the compounds needed for photosynthesis. In return, the algae produce oxygen and help the coral to remove waste. Most importantly, the zooxanthellae supply the coral with glucose, glycerol and amino acids. The coral then uses these to make proteins, fats, and carbohydrates which help produce their calcium carbonate skeleton. The relationship between the zooxanthellae and the coral polyp creates a tight recycling of nutrients in nutrient-poor tropical waters and is the driving force behind the growth and productivity of the reef.

In addition, corals also eat through filter feeding. At night, coral polyps come out of their skeletons to feed, stretching their nematocysts to capture plankton floating by. The prey is then pulled into the polyps' mouths and digested in their stomach cavity.

Dipsastraea speciosa is a hermaphrodite meaning they produce both sperm and egg gametes for reproduction. Mature corals use energy to produce their gametes through meiosis. Dipsastraea speciosa then release their gametes into the water column. The gametes float to the surface and external fertilization takes place. Once the egg is fertilized it becomes a zygote develops into a planktonic larva called planula and floats around the water column by currents. The planula is a type of zooplankton that is able to maneuver by cilia that cover its body. Eventually, the planula settles on a hard substrate and begins to undergo metamorphosis transforming it from a juvenile to an adult. The juvenile polyp begins to lay down a calcium carbonate corallite and begins early morphogenesis of tentacles, septa, and pharynx before larval settlement on the aboral end. Since it is a colonial coral, the polyp then goes through asexual reproduction to form more polyps, expanding the size of the coral colony and increasing the number of coral polyps.

Dipsastraea speciosa is one of the types of corals that synchronizes its time of spawning. This reproductive synchrony increases the likelihood that male and female gametes will meet. Spawning tends to take place in the evening or at night, around the last quarter moon of the lunar cycle.

A full moon is equivalent to four to six hours of continuous dim light exposure, which can cause light-dependent reactions in protein. Corals contain light-sensitive cryptochromes, proteins whose light-absorbing flavin structures are sensitive to different types of light. This allows corals such as Dipsastraea speciosa to detect and respond to changes in sunlight and moonlight.

Moonlight itself may actually suppress coral spawning. The most immediate cue to cause spawning appears to be the dark portion of the night between sunset and moonrise.

Over the lunar cycle, moonrise shifts progressively later, occurring after sunset on the day of the full moon. The resulting dark period between day-light and night-light removes the suppressive effect of moonlight and enables coral to spawn. Light pollution desynchronizes spawning in some coral species.

Dipsastraea speciosa was cited as "Least Concern" on the IUCN Red List in January 2008 although its population trend is decreasing. It faces threats such as residential and commercial development, transportation and services through shipping lanes, fishing, and harvesting for aquatic resources like aquariums, human recreational activities, pollution such as domestic and urban wastewater and climate change. Parts of the range of Dipsastraea speciosa fall within Marine Protected Areas providing them some protection.

Dipsastraea speciosa is often a subject of research because it is a good indicator of the overall health of the ecosystem. It has been studied to better understand reef formation and maintenance of coral reef ecosystems and their response to changing environments. In one study, Dipsastraea speciosa was tested to see how its morphological, physiological or behavioral expression of a genotype is effected by environment-dependent variation. To test this, plastic was transplanted into corals found at shallow and deep depths. It was found that the shallow water corals showed little to no change, but the deeper corals responded by changing dramatically. The oral disks lost their bright green pigmentation and the surrounding tissues turned pale brown. This showed that plasticity in color was evident and probably light-induced.

Source: Wikipedia: Dipsastraea speciosa — https://en.wikipedia.org/wiki/Dipsastraea_speciosa (CC BY-SA 4.0). Accessed 2026-09-23.

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