''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, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

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 on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

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 moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 3 spines and 11 or 12 soft rays and has a base which is roughly equal in length to that of the second dorsal fin. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

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 fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

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 (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

. 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 epithelia ...

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 French Polynesia ( ; ; ) is an overseas collectivity of France and its sole #Governance, overseas country. It comprises 121 geographically dispersed islands and atolls stretching over more than in the Pacific Ocean, South Pacific Ocean. The t ...

, extending south to northern

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

and north to Japan. It is absent 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 the

Persian Gulf The Persian Gulf, sometimes called the Arabian Gulf, is a Mediterranean seas, mediterranean sea in West Asia. The body of water is an extension of the Arabian Sea and the larger Indian Ocean located between Iran and the Arabian Peninsula.Un ...

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 islan ...

, 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 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 ...

and

Polynesia Polynesia ( , ) is a subregion of Oceania, made up of more than 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are called Polynesians. They have many things in ...

. 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 language, Tahitian , ; ) is the largest island of the Windward Islands (Society Islands), Windward group of the Society Islands in French Polynesia, an overseas collectivity of France. It is located in the central part of t ...

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