''Macrognathus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of eel-like

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

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 ...

Mastacembelidae The Mastacembelidae are a family of fishes, known as the spiny eels. The Mastacembelids are part of the Order Synbranchiformes, the swamp eels, which are part of the Actinopterygii (ray-finned fishes). In an evaluation of the family in 2004, the ...

of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

Synbranchiformes Synbranchiformes, often called swamp eels, is an order of ray-finned fishes that are eel-like but have spiny rays, indicating that they belong to the superorder Acanthopterygii. Taxonomy No synbrachiform fossil is known. The Mastacembeloidei were ...

. These fish are distributed throughout most of

South South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

. ''Macrognathus'' species feed on small aquatic

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

e as well as

oligochaete Oligochaeta () is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthworm ...

Appearance and anatomy

Most ''Macrognathus'' species attain in length, but a few surpass this size, with the largest being ''M. aral'' at up to . ''Macrognathus'' are mostly similar to ''

Mastacembelus ''Mastacembelus'' is a genus of many species of spiny eel fish from the family Mastacembelidae. They are native to Africa (c. 45 species) and Asia (c. 15 species). Most are found in rivers and associated systems (even in rapids), but there are al ...

''. However, they differ in a more modified

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

, which may be slightly to significantly larger and longer than those found in ''Mastacembelus''. This serves not only to find food but also to help gather food.

In the aquarium

A number of species of this genus are popular aquarium fish. These include the lesser spiny eel, ''Macrognathus aculeatus'', the spotfinned spiny eel, ''Macrognathus siamensis'', as well as others.

Species

According to

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

, there are currently 25 recognized species in this genus. According to

Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously u ...

, one of these, ''M. malabaricus'', belongs in the genus ''

'' instead of ''Macrognathus'' and another, ''M. taeniagaster'', is considered a junior synonym of ''M. circumcinctus''. * '' Macrognathus aculeatus'' (

Bloch Bloch is a surname of German origin. Notable people with this surname include: A–F * (1859-1914), French rabbi * Adele Bloch-Bauer (1881-1925), Austrian entrepreneur * Albert Bloch (1882–1961), American painter * (born 1972), German motor jour ...

, 1786) (Lesser spiny eel) * '' Macrognathus albus'' * '' Macrognathus aral'' (

& J. G. Schneider, 1801) (Onestripe spiny eel) * '' Macrognathus aureus''

Britz Britz () is a German locality (''Ortsteil'') within the Berlin borough (''Bezirk'') of Neukölln. History The village of ''Britzig'' was first mentioned in 1273. It was incorporated by the 1920 Greater Berlin Act. It is known for being the si ...

, 2010 * '' Macrognathus caudiocellatus'' ( Boulenger, 1893) * '' Macrognathus circumcinctus'' (

Hora Hora may refer to: Companies * Hora (company), a Romanian manufacturer of stringed musical instruments People * Hora (surname) * Hora (musician), member of the Japanese duo Schwarz Stein * Hora people, an indigenous people of Bolivia Places * ...

, 1924) * '' Macrognathus dorsiocellatus''

, 2010 * ''

Macrognathus fasciatus ''Macrognathus fasciatus'' is a species of spiny eel found in the Manimala River and first described in 2014. Macrognathus fasciatus differs from its relative species by the presence of 28–30 dorsal spines, 26–27 vertical lateral lines on t ...

'' Plamoottil &

Abraham Abraham, ; ar, , , name=, group= (originally Abram) is the common Hebrews, Hebrew patriarch of the Abrahamic religions, including Judaism, Christianity, and Islam. In Judaism, he is the founding father of the Covenant (biblical), special ...

, 2014Plamoottil, M. & Abraham, N.P. (2014): ''Macrognathus fasciatus'' (Synbranchiformes; Mastacembelidae) - a new fish species from Kerala, India. ''Journal of Experimental Zoology, India, 17 (1): 49-54.'' * ''

Macrognathus guentheri ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

'' ( F. Day, 1865) (Malabar spiny eel) * ''

Macrognathus keithi ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

'' ( Herre, 1940) * '' Macrognathus lineatomaculatus''

, 2010 * '' Macrognathus maculatus'' ( G. Cuvier, 1832) (Frecklefin eel) * '' Macrognathus malabaricus'' ( Jerdon, 1849) * '' Macrognathus meklongensis'' T. R. Roberts, 1986 * '' Macrognathus morehensis'' Arunkumar & Tombi Singh, 2000 * ''

Macrognathus obscurus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

, 2010 * ''

Macrognathus pancalus ''Macrognathus pancalus'', the barred spiny eel or Indian spiny eel, or পাঁকাল in bengali Bengali or Bengalee, or Bengalese may refer to: *something of, from, or related to Bengal, a large region in South Asia * Bengalis, an ethnic ...

'' F. Hamilton, 1822 (Barred spiny eel) * '' Macrognathus pavo''

, 2010 * ''

Macrognathus pentophthalmos ''Macrognathus pentophthalmos'', the Sri Lanka five-eyed spiny eel, is a small species of spiny eel that is endemic to freshwater habitats in Sri Lanka. Described as a common species as recently as 1980, for unknown reasons its population rapid ...

'' ( Gronow, 1854) ( extinct?) * ''

Macrognathus semiocellatus Macrognathus semiocellatus is a species of ray-finned fish endemic to Cambodia, Laos and Vietnam; it found in marshlands and vegetated water bodies in Mekong Chao Phraya River and Mae Klong. It spends its time during the day buried in silt, sand ...

'' T. R. Roberts, 1986 * '' Macrognathus siamensis'' ( Günther, 1861) (Peacock eel) * ''

Macrognathus siangensis ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

'' Arunkumar, 2016 * ''

Macrognathus taeniagaster ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

'' ( Fowler, 1935) * ''

Macrognathus tapirus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae ...

Kottelat Maurice Kottelat (born 16 July 1957 in Delémont, SwitzerlandCo ...

& Widjanarti, 2005 * ''

Macrognathus zebrinus ''Macrognathus zebrinus'', the zebra spiny eel, is a species of spiny eel endemic to Myanmar, specifically known from the Irrawaddy River, Sittaung River and Salween River and may also occur in Indonesia. It was originally described as ''Mast ...

'' (

Blyth Blyth may refer to: People * Blyth (surname) * Blythe (given name) Places Australia * Blyth, South Australia, a small town Canada * Blyth, Ontario, a village United Kingdom * Blyth, Northumberland, a town ** Blyth Valley (UK Parliament ...

, 1858) (Zebra spiny eel)

References

Mastacembelidae Fish of Southeast Asia {{Synbranchiformes-stub