''Polydactylus plebeius'', the striped threadfin, also known as the common threadfin, Northern threadfin or puttynose, is a species of marine fish native to the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

Description

''Polydactylus plebeius'' is a medium-sized threadfin which 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 but is more commonly . It has a pointed snout and the dorsal profile of the head is nearly straight. There are two separate

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 ...

s, the first containing 8 spines which all have a base of similar thickness and the second dorsal fin has a single spine and 12 or 13 soft rays. 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 11 or 12 soft rays and has a base with is roughly equal in length to that of the second dorsal fin. 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 ...

has 16 to 18 unbranched rays and has a mean length of one fifth of the

standard 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 m ...

and its tip does not extend to the tip of the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

. This species has 5 pectoral filaments, the first is the shortest and it extends to a point just short of or equal to the origin of the pelvic fin. The second to fourth pectoral filaments do not extends as far as the tip of pelvic fin. The fifth pectoral filament is the longest, having a mean length equivalent to one-third of the standard length and it extends beyond the tip of pelvic fin. The caudal fin is deeply forked with both long caudal fin lobes lacking filaments. There are 60-68 pored scales in the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

which is simple and extends from the upper end of gill slit to upper end of the lower lobe of the caudal-fin. The head and upper flanks of the body are silver with a slight blackish tinge. The colour lightens on the lower flanks and the underside is white. The snout is semi-transparent. The first and second dorsal fins, as well as the caudal fin, are pale with blackish rear margins. The membrane of the pectoral fin is blackish. The pectoral filaments are white. The forward margins and origins of the pelvic and anal fins are white, while their other parts are a dusky yellowish white. This species also has 7 or 8 prominent horizontal dark stripes above the lateral line with 7 to 9 faint stripes below it.

Distribution

''Polydactylus plebeius'' is found in the Indo-Pacific from the coast of East Africa where it occurs as far south as South Africa through the Indian Ocean and into the Pacific Ocean as far east as

French Polynesia )Territorial motto: ( en, "Great Tahiti of the Golden Haze") , anthem = , song_type = Regional anthem , song = " Ia Ora 'O Tahiti Nui" , image_map = French Polynesia on the globe (French Polynesia centered).svg , map_alt = Location of Frenc ...

, extending south to northern

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

and north to Japan. It is absent from the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

and the

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Persis, Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a Mediterranean sea (oceanography), me ...

Habitat and biology

''Polydactylus plebeius'' occurs over muddy substrates on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, in estuaries and off coastal beaches down to depths no greater than . It gathers in loose schools. It feeds on small crustaceans, fishes and other benthic organisms.

Fisheries

''Polydactylus plebeius'' is an important species for fisheries in South Asia, Southeast Asia, and particularly in

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

and

Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...

. It is fished using trawls, gill nets, handlines and beach seines.

Species description

''Polydactylus plebeius'' was first formally described as ''Polynemus plebeius'' by Pierre Marie Auguste Broussonet in 1782 with the type locality given as

Tahiti Tahiti (; Tahitian ; ; previously also known as Otaheite) is the largest island of the Windward group of the Society Islands in French Polynesia. It is located in the central part of the Pacific Ocean and the nearest major landmass is Austr ...

References

{{Taxonbar, from=Q2772212 Fish of Thailand Fish of Japan Fish described in 1782 Fish of the Pacific Ocean Fish of the Indian Ocean plebeius Taxa named by Pierre Marie Auguste Broussonet