The spiny chromis (''Acanthochromis polyacanthus'') 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 western Pacific. It is the only member of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Acanthochromis''.

Taxonomy

The spiny chromis was first formally described in 1855 as ''Dascyllus polyacanthus'' by the Dutch ichthyologist Pieter Bleeker with the type locality given as Batman in the Moluccas. It is the only species in the

''Acanthochromis''. The genus name is a compound of ''acanthus'' meaning "spine", probably a reference to the 17 dorsal-fin spines, and ''

Chromis ''Chromis'' is a genus of fish in the family Pomacentridae. While the term damselfish Damselfish are those fish within the subfamilies Abudefdufinae, Chrominae, Lepidozyginae, Pomacentrinae, and Stegastinae within the family Pomacentr ...

'', presumably referring to a relationship to that genus. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''polyacanthus'' means "many-spined".

Distribution and habitat

The spiny chromis is found in the western Pacific Ocean. It is found in western and central Indonesia, Papua New Guinea, northern Australia, and all the islands in the Philippines except

Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...

. They are also found in

Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from New Guinea in the west to the Fiji Islands in the east, and includes the Arafura Sea. The region includes the four independent countries of Fiji, Vanu ...

. This fish usually lives in

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s. This fish is found at a depth range of but is usually found at a depth range of .

Description

Spiny chromis individuals can grow up to a maximum size of as adults. Its fins have 17 dorsal spines, 14 to 16 dorsal rays, 2 anal spines, and 14 to 16 anal rays. This fish is gray on the front and white on the back. The ratio of grey to white varies by specific reef, as there is little interbreeding between reefs due to lack of pelagic larval period. Grey color can range from a blue-grey to brown as the fish matures. The top of its dorsal fin and the bottom of its anal fin is black. Some individuals are gray with a yellow horizontal line in the middle.

Ecology

Diet

This fish is planktonivorous and algivorous, and steals algae from algae-farming species of damselfish. Younger individuals have been known to eat mucus off the adults.

Life Cycle

The spiny chromis, unlike many other

coral reef fish Coral reef fish are fish which live amongst or in close relation to coral reefs. Coral reefs form complex ecosystems with tremendous biodiversity. Among the myriad inhabitants, the fish stand out as colourful and interesting to watch. Hundreds ...

es, has direct development of their larvae, which means that the parents protect their brood from the egg stage (which are laid on the reef), through hatching and onto the fully developed juvenile stage. There is no pelagic larval stage unlike the vast majority of coral reef fishes. This form of direct development means that the offspring often take up residence on the reef not far from where they were hatched. Consequently, high levels of local adaptation to their local environment has been recorded in this species.Fulton CJ, Binning SA, Wainwright PC, Bellwood DR (2013) Wave-induced abiotic stress shapes phenotypic diversity within a coral reef fish across a geographical cline. ''Coral Reefs'' 32:685-689.

References

External links

* {{Taxonbar, from=Q1851735 Chrominae Fish described in 1855 Taxa named by Pieter Bleeker