Synbranchiformes

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Synbranchiformes
Monopterus albus 4.jpg
Monopterus albus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Clade: Percomorpha
Order: Synbranchiformes
Berg, 1940 [1]
Type species
Synbranchus marmoratus
Bloch, 1795 [2]
Families

Synbranchidae
Chaudhuriidae
Mastacembelidae
Indostomidae

Contents

Synbranchiformes, often called swamp eels, though that name can also refer specifically to Synbranchidae, 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 removed from the Perciformes and added to the Synbranchiformes after a phylogenetic analysis by Johnson and Patterson. These authors consider the Synbranchiformes to be part of a monophyletic group called Smegmamorpha, also containing Mugilimorpha, Atherinomorpha, Gasterosteiformes, and Elassomatidae. [3] Later authors have proposed that the Synbranchiformes along with the Anabantiformes, Carangiformes, Istiophoriformes and Pleuronectiformes form a sister clade to the Ovalentaria which has been called the “Carangimorpharia” but in the 5th Edition of Fishes of the World this clade remained unnamed and unranked. [4]

There are a total of about 99 species divided over 15 genera in three families. [3] There are two suborders: Synbranchoidei and Mastacembeloidei, or Opisthomi. The Synbranchoidei has one family, the Synbranchidae; four genera; and 17 species. [3] The Mastacembeloidei has two families: Chaudhuriidae, with four genera and five species, and Mastacembelidae, with three genera and about 26 species.

Modern studies have placed Indostomus , the sole genus within the family Indostomidae, within the Synbranchiformes. [5]

Description

These eel-like fishes range in size from 8–48  inches (20–150  cm). Although they are eel-like, they are not related to true eels (Anguilliformes). The premaxillae are present as distinct bones and are nonprotrusible. [3] The gills are poorly developed, and their openings are usually single, small, confluent across the breast, and restricted to the lower half of the body. [3] Oxygen is absorbed through the membranes of the throat or intestine. The dorsal and anal fins are low and continuous around the tail tip. Pelvic fins are absent. [3] Scales are either absent or very small. They lack a swim bladder.

Distribution

These fishes are distributed in tropical America, tropical Africa, southeastern and eastern Asia, East Indies, and Australia. The three families each have a somewhat different distribution: The Synbranchidae are found in Mexico, Central and South America, West Africa (Liberia), Asia, Hawaii, and the Indo-Australian Archipelago. [3] The Mastacembelidae are found in Africa and through Syria to Maritime Southeast Asia, China, and Korea. [3] The Chaudhuriidae are found in northeastern India through Thailand to Korea (including parts of Malaysia and Borneo). [3]

Habitat

All except three species occur in fresh water. [3] They usually are found in swamps, caves, and sluggish fresh and brackish waters. When found in pools, they typically are associated with leaf litter and mats of fine tree roots along the banks. Swamp eels are capable of overland excursions, and some can live out of water for extended periods of time. Some species are burrowers. Four species are found exclusively in caves: Rakthamichthys eapeni and R. roseni from India, Ophisternon candidum from Australia, and O. infernale from Mexico. [6] One species, O. bengalense , commonly occurs in coastal areas of southeastern Asia.

Ecology

Some species are considered air-breathing fishes because of their ability to breathe by highly vascularized buccopharyngeal pouches (pharynx modified for breathing air). They usually are active only at night.

They feed on benthic invertebrates, especially larvae, and fishes.

At least some of the species of the family Synbranchidae, that is, O. infernale, are sexually dimorphic. Adult males grow a head hump, and males are larger than females. These fishes lay about 40 spherical eggs per clutch. The eggs measure between 0.05 and 0.06 in (1.2–1.5 mm) in diameter and have a pair of long filaments for adhesion to the substrate. Reproduction takes place during the wet season, which lasts for several months, during which females probably spawn more than once. Data acquired from studying juvenile growth and the length of representative individuals within a population suggests that they are a short-lived species that matures during the first year, with few individuals surviving to the second breeding season.

Importance to humans

In some parts of Asia, swamp eels and one species of spiny eel, Mastacembelus erythrotaenia , are valued as food and sometimes are kept in ponds or rice fields. Except for a few mastacembelids, they are rarely seen in home aquaria. The fish have numerous sharp dorsal spines and belly thorns which, together with its sliminess make them extremely difficult to handle. The spines must be cut off with scissors before consumption.

Tyre track eel caught in River Tlawng, Mizoram, India 2012 Tyre track eels.jpg
Tyre track eel caught in River Tlawng, Mizoram, India 2012

Sources

Books

Periodicals

Other Information

Related Research Articles

<span class="mw-page-title-main">Swamp eel</span> Family of fishes

The swamp eels are a family (Synbranchidae) of freshwater eel-like fishes of the tropics and subtropics. Most species are able to breathe air and typically live in marshes, ponds and damp places, sometimes burying themselves in the mud if the water source dries up. They have various adaptations to suit this lifestyle; they are long and slender, they lack pectoral and pelvic fins, and their dorsal and anal fins are vestigial, making them limbless vertebrates. They lack scales and a swimbladder, and their gills open on the throat in a slit or pore. Oxygen can be absorbed through the lining of the mouth and pharynx, which is rich in blood vessels and acts as a "lung".

<span class="mw-page-title-main">Earthworm eel</span> Family of fishes

Chaudhuriidae, is a family of small freshwater eel-like fish related to the swamp eels and spiny eels, commonly known as the earthworm eels. The known species are literally the size and shape of earthworms, thus the family name. While one species, Chaudhuria caudata was reported from the Inle Lake by Nelson Annandale in 1918, the others have been only recently reported, all in the eastern Asia area, from India to Korea.

<span class="mw-page-title-main">Gasterosteoidei</span> Order of fishes

Gasterosteoidei is a suborder of ray-finned fishes that includes the sticklebacks and relatives, the 5th edition of Fishes of the World classifies this suborder within the order Scorpaeniformes.

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.

A blind fish is a fish without functional eyes. Most blind fish species are found in dark habitats such as the deep ocean, deep river channels and underground.

Macrognathus is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes.

<span class="mw-page-title-main">Liberian swamp eel</span> Species of fish

The Liberian swamp eel is a species of fish in the family Synbranchidae. It is indigenous to Liberia. It has also been found in Sierra Leone, with an unconfirmed report from Côte d'Ivoire. It was first described by Jacques Pellegrin in 1922 as Typhlosynbranchus boueti, but was later moved to Monopterus. However, a 2020 study revived Typhlosynbranchus. Due to the deficiency in data, the species has not been classified with respect to endangerment.

<span class="mw-page-title-main">Mexican blind brotula</span> Species of fish

The Mexican blind brotula is a species of viviparous brotula endemic to Mexico, where it is found in sinkholes and caves. It is known as sak kay in Mayan and dama blanca ciega in Spanish. This cavefish grows to a standard length of 9.7 cm (3.8 in). It is the only known member of its genus.

<span class="mw-page-title-main">Blind cave eel</span> Species of fish

The blind cave eel is a species of cavefish in the family Synbranchidae. It is the longest cavefish in Australia and one of the only three vertebrates in Australia that is restricted to underground waters, the other being the blind gudgeon and the Barrow cave gudgeon. It is blind, its body is eel-like and elongated, and it has a non-pigmented skin with colours ranging from white to pink.

<i>Ophisternon</i> Genus of fishes

Ophisternon is a genus of swamp eels found in fresh and brackish waters in South and Southeast Asia, New Guinea, Australia, Middle America and West Africa. Two species are blind cave-dwellers.

The blind swamp eel is a species of fish in the family Synbranchidae. It is endemic to Mexico where it lives in cave systems and is known in Spanish as the anguila ciega. The International Union for Conservation of Nature has rated this cavefish as "endangered".

<span class="mw-page-title-main">Cavefish</span> Fish adapted to life in caves

Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.

<i>Indostomus</i> Genus of fishes

Indostomus is a genus of small fishes native to slow moving or stagnant freshwater habitats in Indochina. It is the sole genus of the monogeneric family Indostomidae, Long considered to be sticklebacks, within the order Gasterosteiformes, modern analyses place the Indostomids within the order Synbranchiformes, related to the spiny eels and swamp eels.

<i>Synbranchus</i> Genus of fishes

Synbranchus is a genus of swamp eels native to Central and South America.

Ophichthys desilvai is a commercially important, air-breathing species of fish in the family Synbranchidae. It is endemic to Sri Lanka and is the only endemic synbranchid from there.

<i>Ophisternon bengalense</i> Species of fish

Ophisternon bengalense the Bengal eel, Bengal mudeel or onegill eel, is a species of fish in the family Synbranchidae. It is endemic to freshwater and brackish water rivers and swamps in Oceania and South Asia. It is normally 100 cm in maximum length.

<i>Synbranchus marmoratus</i> Species of fish

Synbranchus marmoratus, the marbled swamp eel, neotropical swamp eel, marmorated swamp eel, mottled swamp eel, zange, or muçum is a species of swamp eel native to Central and South America, including the island of Trinidad and Grenada .

Rakthamichthys rongsaw is a species of swamp eel discovered in the Khasi Hills in northeast India. The researchers were searching for caecilians, when they uncovered the eel in soil.

<span class="mw-page-title-main">Synbranchinae</span> Subfamily of fishes

Synbranchinae is a subfamily of swamp eel, consisting of six of the ten genera in the family Synbranchidae. The remaining genus, the monotypic Macrotrema is the only one in the other subfamily Macrotreminae. The subfamily occurs in the Neotropics, Afrotropics and Asia.

<i>Ophichthys</i> Genus of fishes

Ophichthys is a genus of swamp eels native to South Asia. They live in freshwater or subterranean habitats, and some have a fossorial lifestyle.

References

  1. ↑ Robert A. Travers (1985). "A review of the Mastacembeloidei, a suborder of Synbranchoform teleost fish Part 2: Phylogenetic analysis". Bulletin of the British Museum (Natural History). 47: 83–151.
  2. ↑ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Synbranchus". Catalog of Fishes . California Academy of Sciences . Retrieved 11 November 2019.
  3. 1 2 3 4 5 6 7 8 9 10 Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN   0-471-25031-7.
  4. ↑ J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. p. 380. ISBN   978-1-118-34233-6.
  5. ↑ Betancur-R, Ricardo; Wiley, Edward O.; Arratia, Gloria; Acero, Arturo; Bailly, Nicolas; Miya, Masaki; Lecointre, Guillaume; Ortí, Guillermo (2017-07-06). "Phylogenetic classification of bony fishes". BMC Evolutionary Biology. 17 (1): 162. doi: 10.1186/s12862-017-0958-3 . ISSN   1471-2148. PMC   5501477 . PMID   28683774.
  6. ↑ Romero, Aldemaro; Paulson, Kelly M. (2001). "It's a Wonderful Hypogean Life: A Guide to the Troglomorphic Fishes of the World". Environmental Biology of Fishes. 62 (1/3): 13–41. doi:10.1023/A:1011844404235. S2CID   34127843.
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