The threespot dascyllus (''Dascyllus trimaculatus''), also known as the domino damsel or simply domino, is a species of

damselfish Damselfish are those fish within the subfamilies Abudefdufinae, Chrominae, Lepidozyginae, Pomacentrinae, and Stegastinae within the family Pomacentridae. Most species within this group are relatively small, although the four largest speci ...

from the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Pomacentridae Pomacentridae is a family of ray-finned fish, comprising the damselfishes and clownfishes. This family were formerly placed in the order Perciformes or as indeterminate percomorphs, but are now considered basal blenniiforms. They are primaril ...

. It is native to the Indo-Pacific from the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

and

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

, to the

Pitcairn The Pitcairn Islands ( ; Pitkern: '), officially Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islan ...

Islands, southern

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, and can also be found in some parts of the Philippines.

Taxonomy

''Dascyllus trimaculatus'' is one of four species in its namesake ''D. trimaculatus''

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

. The other three species in this complex are '' D. albisella'', '' D. strasburgi'', and '' D. auripinnis''. ''D. trimaculatus'' and ''D. auripinnis'' are parapatric (their ranges overlap in the Northern Cook Islands), but the four species are otherwise all

allopatric Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

. The ''D. trimaculatus'' complex diverged from the ''D. reticulatus'' complex 3.9 million years ago, in the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. Mitochondrial genome analysis found that ''D. trimaculatus'' itself can be split into three populations: Indian Ocean, southern French Polynesia, and West-Central Pacific. ''D. auripinnis'' has been found to clade with the West-Central Pacific population of ''D. trimaculatus'', which raises some doubts as to the former's validity. Fish described as ''D. trimaculatus'' in

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

have yellow pelvic and anal fins, and streaks of orange in the dorsal and caudal fins. These physically appear intermediate between ''D. trimaculatus'' and ''D. auripinnis''; genomic analysis shows that they are a result of

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introg ...

of ''D. auripinnis'' into ''D. trimaculatus'' through repeated

backcrossing Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and produc ...

Etymology

''Trimaculatus'', meaning "three-spotted", refers to the fish's three white spots. This accounts also for the common name "domino".Siliotti, A. (2002) ''fishes of the red sea'' Verona, Geodia

Description

Its grey to black body has two lateral white spots and one between the eyes like domino hence the name; the threespot dascyllus grows up to in length. Coloration is somewhat variable; the spot on the forehead may be absent and the lateral spots very much reduced. It feeds on

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s and other

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

Habitat

Generally, adults are found in small groups around

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

heads or large rocks. Juveniles may be found associated with large

sea anemone Sea anemones ( ) are a group of predation, predatory marine invertebrates constituting the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemone ...

s or sheltering between the spines of diadema

sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...

s or branching corals.Lieske, E. and Myers, R.F. (2004) ''Coral reef guide; Red Sea'' London, HarperCollins This species may be found to depths of 55 m.

Biology

Like other species in the ''D. trimaculatus'' species complex, ''D. trimaculatus'' recognizes conspecifics using sound.

Symbiosis with anemones

Juveniles dwell with anemones such as '' Stichodactyla mertensi'' for shelter. This relationship with anemones is lost as they mature into adults. On very rare occasions, the juveniles may use corals instead. Juveniles may co-habit their hosted anemones with certain species of

clownfish Clownfishes or anemonefishes (genus ''Amphiprion'') are saltwater fishes found in the warm and tropical waters of the Indo-Pacific. They inhabit mainly coral reefs and have a distinctive colouration typically consisting of white vertical bars on ...

, although more aggressive clownfish species may refuse to share anemones. Symbiosis with anemones is also seen in every other species of the ''D. trimaculatus'' species complex.

In aquarium

During the juvenile period, they live with the sea anemone. They grow fast and can grow up to in length in a large fish tank.Youtube <> Creatures section, Damselfish - Author:Sublanding Fish 020-06-19/ref>

Gallery

File:Three-spot Dascyllus, Butaritari Island, Kiribati imported from iNaturalist photo 343836700.jpg, In Fiji, showing yellow colouration from '' D. auripinnis'' introgression. File:Dascyllus trimaculatus Domino damsel.jpg, Threespot dascyllus and anthias grouping over coral near Taba, Egypt File:Juvenile Three Spot Dascyllus and Blackfoot Anemone Fish.jpg, A pair of juvenile three-spot dascylluses with their anemone in the Maldives: A pair of black-foot anemonefish can be seen to the top. File:Maldive anemonefish.jpg, Juvenile threespot dascyllus (left) and a pair of Maldives anemonefish associated with the sea anemone '' Heteractis magnifica'' File:Taman-nasional-wakatobi.jpg, Shoals of threespot dascyllus fish at

Wakatobi National Park Wakatobi National Park is a marine national park in Southeast Sulawesi, Indonesia. It was established in 2002. The name of Wakatobi is a portmanteau of the four main Tukangbesi Islands: Wangi-wangi, Kaledupa, Tomia, and Binongko. Since 2005 t ...

References

External links

* trimaculatus Fish of the Red Sea Fish described in 1829 Taxobox binomials not recognized by IUCN {{Pomacentridae-stub