''Pseudanthias bicolor'', the bicolor anthias or yellowback basslet is a species of marine

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 h ...

from the subfamily Anthiinae of the

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

Serranidae The Serranidae are a large family of fishes belonging to the order Perciformes. The family contains about 450 species in 65 genera, including the sea basses and the groupers (subfamily Epinephelinae). Although many species are small, in some ca ...

, the

grouper Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes. Not all serranids are called "groupers"; the family also includes the sea basses. The common name "grouper" is ...

s and sea basses. It is from the Indo-Pacific Ocean. It occasionally makes its way into the aquarium trade. It grows to a size of 13 cm in length.

Description

''Pseudanthias bicolor'' has a relatively elongated, laterally compressed body which has a standard length which is around three times its depth. It has a moderately large, oblique, terminal mouth, although in males the thickening of the upper lip causes it to be slightly inferior. The

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

is level with the rear edge of the eye. 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 c ...

has 10 spines ands 16-18 soft rays while the anal fin contains 3 spines and 7-8 soft rays. The colouration of this species is

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

, the males are more intensely coloured having a violet body with a yellow back, the yellow colour continuing on to the upper lobe of 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 ...

and the dorsal fin has a purple margin.. The females are normally lavender in colour and have a yellow back and caudal fin. The males also have two yellow-tipped filaments at the origin of the dorsal fin which they use when displaying. The 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 ...

recorded is .

Distribution

''Pseudanthias bicolor'' is the most widespread species in the genus ''

Pseudanthias ''Pseudanthias'' is a genus of colourful reef fishes of the subfamily Anthiinae, part of the family Serranidae, the groupers and sea basses. They are found in the Indo-Pacific. The species belonging to this genus have a diet consisting of zooplan ...

'' and has a wide Indo-Pacific distribution from Réunion and Mauritius in the west to

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

and the Line Islands, north as far as the

Ryukyus The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ōsumi, Tokara, Amami, Okinawa, and Sakishima Islands (further divided into the Miyako and Yaeyama Islands), with Yonaguni ...

south of Japan and south to northeastern Australia.

Habitat and biology

''Pseudanthias bicolor'' is a rather uncommon fish which is found in lagoon patch reefs and along outer reef slopes. It can be found in deep coastal reefs to outer reef slopes, in areas where there is a strong current. The species of the genus ''Pseudanthias'' feed on zooplankton. These fish are

protogynous hermaphrodite Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...

s and each social group will contain a dominant male and a number of females and juveniles. When the dominant male dies then the largest female will change sex.

Taxonomy

''Pseudanthia bicolor'' was first formally described as ''Anthias bicolor'' in 1979 by the

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

ichthyologist John E. Randall (1924-2020) with the type locality given as Waianae coast off Pokai Bay on

Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O� ...

in Hawaii.

Utilsation

''Pseudanthias bicolor'' is traded within the aquarium trade.

References

{{DEFAULTSORT:Pseudanthias Bicolor bicolor Fish of Hawaii Taxa named by John Ernest Randall Fish described in 1979