A species of mushroom coral discovered in Vanuatu demonstrates the extreme marine biodiversity of the Pacific's 'coral triangle'
The family Fungiidae are commonly known as mushroom corals because of a strong resemblance to the underside of the cap of a gilled mushroom. They are distributed in tropical seas of the Indo-Pacific and may be found among a diversity of reefs: shallow flats, deep reefs and reefs both offshore and situated near the mouths of rivers. Most mushroom corals detach in the adult stage and become solitary and free living, although some remain connected to their substrate. Dense swarms of adults are observed consisting of one or more of the 50 species in the family.
The south-eastern area of Espiritu Santo was surveyed during the Santo 2006 expedition organised by the Muséum national d'Histoire naturelle, Paris, Pro-Natura International and the Institut de recherche pour le développement with funds from the Total and Sloan foundations. Previous studies of Vanuatu, south-west Pacific, had documented the presence of only 20 species of mushroom corals. Following Santo 2006, that number increased to 36, including two new species, one named Sandalolitha boucheti by Dr Bert W Hoeksema of the Netherlands Centre for Biodiversity Naturalis, Leiden.
In September 2006, 25 dives were made over a period of 15 days resulting in more than a dozen new species records for mushroom corals in Vanuatu. Sandalolitha boucheti is so far known only from Vanuatu and north-eastern Borneo in the Sulawesi Sea. The new species is smaller than its close relatives with a length of 8cm to 13.5cm. It is irregularly circular or oval in shape, highly arched to slightly cupped with a concave upper surface. Light brown in colour, it has finer and more densely arranged, radially aligned plates called septa and surface ornamentations.
In all, the expedition documented 36 species of mushroom corals. Five of the species were represented by only one specimen each. This makes it unlikely that all species were found and additional records should be expected. Taken as a proportion of all species of the regional fauna, this also implies that the current count of 296 coral species for Vanuatu is similarly incomplete.
A roughly triangular-shaped area of extreme marine biodiversity encompasses tropical waters from the Philippines in the north and eastern Malaysia and Indonesia in the west to the Solomon Islands in the east. This so-called "coral triangle" includes more than 5.5m sq km and is home to about 500 species of reef corals. Some sites in the triangle include fewer than 30 mushroom coral species. If proportions hold, the reef fauna of Vanuatu may ultimately argue for its inclusion in the triangle, too.S boucheti is just the latest of more than 70 species named in honour of Professor Philippe Bouchet. Bouchet is head of malacology in the natural history museum in Paris and has named more than 500 species new to science himself. He is a leading voice for the exploration and conservation of marine biodiversity and a commissioner of the International Commission on Zoological Nomenclature, the body based in London that maintains the code by which animal names are governed worldwide. Bouchet was also leader of the marine component of the Santo 2006 expedition.
In 2009, the BBC reported that a mushroom coral, Fungia scruposa, was observed off the coast of Israel feeding on an adult moon jellyfish approximately its own size. Like other corals, their normal diet consists of microscopic plankton. A nutrient rich current had enabled a bloom of jellies that may have improved the coral's chances of catching one.