Blastomussa merleti

Lore & Background

Young colonies of Blastomussa merleti have each corallite extending out from a common, dome-shaped centre. Over time, these individual corallites become separated and the colony could be considered a group of cloned, solitary individuals. The corallites are less than 7 mm in diameter, and the septa have toothed margins arranged in two cycles, with only the first cycle reaching the central columella. The polyps are only extended at night. This coral may be dark red, pink, orange, brown, or dark grey, often with contrasting green oral discs.

Blastomussa merleti is native to the Indo-Pacific region, coexisting with other species in the same genus, B. wellsi and B. loyae. Its range extends from the Red Sea and the coast of East Africa, through the Indian Ocean, to northern and western Australia, Japan, the East China Sea, and the islands of the oceanic West Pacific. It inhabits a range of reef habitats, including steep slopes and crevices, at depths down to about 50 metres.

The species is moderately common with a widespread distribution. The population trend is unknown, but it is probable that the number of mature colonies is decreasing as a result of destruction of its reef habitats. Its conservation status has been assessed as being of 'least concern' by the International Union for Conservation of Nature.

Reader's Guide

Blastomussa merleti is notable for its uncertain taxonomic placement—the family of the genus Blastomussa remains unclear. Its bright colors make it a candidate for reef aquaria, where it is said to be moderately easy to care for. In the aquarium, the polyps collect food particles with their tentacles, obtain energy from symbiotic zooxanthellae, and can extract organic carbon from the water. The species is moderately common and widespread, but its population trend is unknown, and it is likely declining due to reef habitat destruction. The IUCN has assessed it as 'least concern,' reflecting its current status despite potential threats. Its ability to form colonies that eventually separate into cloned solitary individuals is a distinctive biological characteristic. The coral's nocturnal polyp extension and varied coloration, often with contrasting green oral discs, contribute to its appeal in both natural reef ecosystems and captive settings.

Did You Know?

• It is unclear in which family the genus Blastomussa belongs.
• Young colonies have corallites extending from a common dome-shaped centre, but over time they become separated cloned individuals.
• It can extract organic carbon from the water in addition to feeding with tentacles and using symbiotic zooxanthellae.

Taxonomic Identity and Genus Context

Blastomussa merleti is a species of large polyp stony coral that belongs to the genus Blastomussa, which is classified within the family Plerogyridae. The species was originally described by Wells in 1961, and it carries the taxonomic notation (Wells, 1961), indicating it was later reclassified into the genus Blastomussa from a different original placement. As a member of the large polyp stony coral group, it occupies a particular ecological and morphological niche among reef-building organisms. The genus Blastomussa itself is recognized by the World Register of Marine Species as containing six valid species, placing B. merleti among a relatively small but distinct group of corals. Its placement in Plerogyridae situates it within a broader family of stony corals, and the large-polp designation distinguishes it from smaller-polyped coral groups. The species epithet merleti follows standard taxonomic nomenclature conventions, honoring an individual whose name is preserved in the scientific literature.

The Genus Roster and Species Diversity

The genus Blastomussa, as recognized by the World Register of Marine Species, encompasses six described species, each attributed to different taxonomists across a span of over seven decades. Beyond B. merleti, the roster includes B. loyae described by Head in 1978, B. omanensis named by Sheppard and Sheppard in 1991, B. simplicitexta described by Umbgrove in 1942 and now marked as extinct with the dagger symbol, B. vivida described by Benzoni, Arrigoni, and Hoeksema in 2014, and B. wellsi described by Wijsman-Best in 1973. The presence of an extinct species, B. simplicitexta, indicates that the genus has a fossil record and that not all members survive to the present day. The geographic hint embedded in B. omanensis suggests a connection to the waters around Oman. The span from 1942 to 2014 in the original descriptions shows that taxonomic work on this genus continued well into the twenty-first century, with new species still being formally recognized.

Presence in Reef Aquariums

One of the notable aspects of the genus Blastomussa, and by extension B. merleti, is its occasional presence in the reef aquarium hobby. Members of this genus are sometimes kept in captive marine environments, where they are appreciated as part of curated reef displays. The fact that these large polyp stony corals find a place in aquarium settings speaks to their relative manageability in captive conditions compared to some other coral groups. The ReefCorner Database maintains a dedicated entry for B. merleti, indicating that the species has been documented and discussed within the aquarium community. This database entry serves as a reference point for hobbyists and aquarists seeking information about the species. The inclusion of Blastomussa species in reef aquariums also highlights the broader intersection between marine taxonomy and the hobbyist trade, where scientific names and classifications become practical tools for identification and care. The qualifier sometimes in the literature suggests that while these corals do appear in aquariums, they are not among the most commonly traded or widely available species.

Taxonomic History and Scientific Recognition

The taxonomic history of Blastomussa merleti reflects a broader pattern of coral classification work spanning the twentieth and early twenty-first centuries. Wells described the species in 1961, and the parenthetical notation in its current binomial signals that the species was originally placed in a different genus before being transferred to Blastomussa. This reclassification is a common occurrence in coral taxonomy as understanding of morphological and genetic relationships evolves. The genus itself has been the subject of work by numerous taxonomists, including Head, the Sheppards, Umbgrove, Benzoni, Arrigoni, Hoeksema, and Wijsman-Best, each contributing a species description between 1942 and 2014. The World Register of Marine Species serves as the authoritative body that currently recognizes all six species within the genus. The fact that B. vivida was not described until 2014 demonstrates that even well-studied coral groups continue to yield new taxa to science, and that the taxonomic picture of Blastomussa remains a living document subject to revision and expansion.