''Plectorhinchus caeruleonothus'', the blue bastard, is a species of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

, a sweetlips belonging to the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Plectorhinchinae, one of two subfamilies in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Haemulidae Haemulidae is a family of fishes in the order Perciformes known commonly as grunts. It is made up of the two subfamilies Haemulinae (grunters) and Plectorhynchinae (sweetlips), which in turn contain about 133 species in 19 genera. These fish ar ...

, the grunts. It was discovered in Australia in 2015.

Description

''Plectorhinchus caeruleonothus'' adults are mostly silvery-grey in colour but with the cheek and the operculum are uniformly bluish-grey. The orbit of the eye and upper edge of upper jaw are sooty yellow while the posterior edge of the gill membrane is silvery-grey. The juveniles are blackish brown, marked with 10 uneven, horizontal, slender white stripes on the head and body. The

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is marked with diagonal white bars which converge on the central margin while the

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s are yellow with a dark brown blotch on the middle of its inner base. The

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

contains 12 spines and 18-20 soft rays while the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

has 3 spines and 6-7 soft rays. This species attains a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of .

Distribution

''Plectorhinchus caeruleonothus'' is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Australia. It ranges from

Rottnest Island Rottnest Island ( nys, Wadjemup), often colloquially referred to as "Rotto", is a island off the coast of Western Australia, located west of Fremantle. A sandy, low-lying island formed on a base of aeolianite limestone, Rottnest is an A-class ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

around the northern coast to

Lizard Island Lizard Island is an island on the Great Barrier Reef in Queensland (Australia), northwest of Brisbane and part of the Lizard Island Group that also includes Palfrey Island. It is part of the Lizard Island National Park. Lizard Island is within ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

Habitat and biology

''Plectorhinchus caeruleonothus'' is found over sand, rubble and reef substrates, although it prefers intertidal areas or reefs in shallow water. It has been taken as deep as . Larger individuals are solitary, spending the day foraging over quite open areas of sand or silt. These fish have frequently been recorded interacting in highly aggressive conflicts with other conspecifics. such confrontations involve the individuals coming together face to face and locking their jaws, as well as participating in prolonged and violent struggles close to the top of the water column.

Discovery, systematics and naming

''Plectorhinchus caeruleonothus'' was previously considered to be a legendary fish which existed only in fishermen's tales. The fish is very difficult to catch. ''Plectorhinchus caeruleonothus'' was identified through several features unique to it, such as a distinctive pattern on juveniles and small nostrils. It is thought that the fish likely evolved its tough ways to survive the many sharks and crocodiles that share its habitat in reef waters off northern Australia. It was formally described in 2015 by Jeffrey W. Johnson and Jessica Worthington Wilmer with the type locality given as Boyd Bay, southwest of

Weipa Weipa () is a coastal mining town in the local government area of Weipa Town in Queensland. It is the largest town on the Cape York Peninsula. It exists because of the enormous bauxite deposits along the coast. The Port of Weipa is mainly involv ...

in Queensland. Previously, this species was thought to be a taxon

synonymous A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

with the minstrel sweetlips ('' Plectorhinchus schotaf'') of the western Indian Ocean, as were the sombre sweetlips ('' Plectorhinchus unicolor'') of Japan to northern Australia and '' Plectorhinchus griseus'' from India and Sri Lanka, but all are now recognised as valid species The specific name is a compound of ''caeruleus'' meaning “blue”, which refers to the blue sheen in life, and ''nothus'' meaning “bastard”, reflecting the name given to this species by anglers.

Utilisation

''Plectorhinchus caeruleonothus'' Is sometimes taken as bycatch in commercial fisheries. It is sought after by recreational anglers, mainly due to the difficulty of catching it. The flesh is not regarded as highly palatable.

References

{{Taxonbar, from=Q21304440 Fish of Australia caeruleonothus Fish described in 2015