Polycyathus muellerae
Source-cited species reference: taxonomy from WoRMS, biology from SeaLifeBase, occurrence map from GBIF, description from Wikipedia.
Polycyathus muellerae is a small species of coral in the family Caryophylliidae in the order Scleractinia, the stony corals. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea. It is a large polyp, colonial coral and grows under overhangs and in caves as part of an assemblage of organisms suited to these poorly-lit sites.
- Scientific name
- Polycyathus muellerae
- Authority
- (Abel, 1959)
- Family
- Caryophylliidae
- Order
- Scleractinia
- Habitat zone
- sessile
- Gbif occurrence records
- 263
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Cnidaria · Class: Hexacorallia · Order: Scleractinia · Family: Caryophylliidae · Genus: Polycyathus.
Accepted name: Polycyathus muellerae · Authority: (Abel, 1959) · Taxonomic status: accepted · AphiaID: 135165.
Synonyms and superseded combinations recorded for this taxon: Cladocora caespitosa f. incrostante Rossi, 1957; Cladocora caespitosa var. mulleri Abel, 1959; Cladocora cespitosa var. mulleri Abel, 1959; Cladocora muellerae Abel, 1959; Polycyathus banyulensis Best, 1968; Polycyathus mediterraneus Best, 1968.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=135165 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (SeaLifeBase)
Measured values published by SeaLifeBase for Polycyathus muellerae. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Habitat zone: sessile.
SeaLifeBase notes: Known from infra- and circalittoral zones (Ref. 85338).
Source: SeaLifeBase species summary (SpecCode 46384) — https://www.sealifebase.se/summary/Polycyathus-muellerae.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
263 georeferenced occurrence records for Polycyathus muellerae are published through GBIF from 12 countries or marine areas. The map above plots 42 distinct locations from a sample of 263 records, omitting 16 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: France (175); Spain (39); Italy (24); Greece (14); Israel (2); Portugal (2); Tunisia (2); Cyprus (1); Croatia (1); Lebanon (1); Malta (1); Seychelles (1).
Marine regions with a valid WoRMS distribution record: European waters (ERMS scope); Mediterranean Sea; East North Atlantic; Greek Exclusive Economic Zone; Caribbean Sea; Trinidad and Tobago; Spanish Exclusive Economic Zone; French Exclusive Economic Zone; Tunisian Exclusive Economic Zone; Israeli Exclusive Economic Zone; Moroccan Exclusive Economic Zone; Maltese Exclusive Economic Zone; Croatian Exclusive Economic Zone.
Source: GBIF Occurrence Search (taxonKey 5184509) — https://www.gbif.org/occurrence/search?taxon_key=5184509&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=135165 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.
Description and natural history (Wikipedia)
Polycyathus muellerae is a colonial species of coral with large polyps. The individual polyps are at first joined by an encrusting basal lamina but with time this may get worn away and other organisms may take up residence between the polyps. Growth in this species is achieved by budding from the basal lamina, and the rather diffuse colonies may be a metre or so in diameter. Each individual polyp sits in a corallite or stony cup, about 6 mm in diameter and 10 mm high. The corallites have up to four cycles of toothed septa (stony ridges) making 48 septa in total. Both corallites and polyps are brown and the tentacles, 3 to 4 mm long, have white granulations and white cylindrical tips.
This species is native to the northeastern Atlantic Ocean, the North Sea, the English Channel and the Mediterranean Sea. It normally avoids direct sunlight and grows in caves and under overhangs at depths of 30 m or less.
P. muellerae is a non-zooxanthellate coral; it does not have a symbiotic relationship with microscopic dinoflagellates as do most corals, instead obtaining all its nutrition from the planktonic organisms caught by the polyps. Asexual reproduction by budding increases the size of the colony. Sexual reproduction has not been observed in this species, but the fact that the coral has a widespread distribution suggests that it is likely to occur. This coral is sometimes parasitized by the barnacle Megatrema anglicum.
A study of the assemblages of organisms living in caves in southern Italy found that in the best-lit places near the entrance, algae were plentiful and in the deepest parts of the interior sponges predominated. In the intermediate zone there were corals including Polycyathus muellerae, hydroids, serpulid worms, bivalves, worm snails, bryozoans and sea squirts.
Source: Wikipedia: Polycyathus muellerae — https://en.wikipedia.org/wiki/Polycyathus_muellerae (CC BY-SA 4.0). Accessed 2026-09-23.
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