''Rakthamichthys'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of swamp eels that are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. Three species are known from the Western Ghats and one is known from

Northeast India , native_name_lang = mni , settlement_type = , image_skyline = , image_alt = , image_caption = , motto = , image_map = Northeast india.png , ...

. All species live underground, with one species (''R. rongsaw'') having a

fossorial A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric eviden ...

lifestyle and three species (''R. digressus'', ''R. roseni'', and ''R. indicus'') being troglobitic in nature. All species display adaptations to this lifestyle, including a bright red coloration and highly reduced eyes.

Taxonomy

All four species were formerly classified in the genus ''

Monopterus ''Monopterus'' is a genus of swamp eels native to Asia. They live in various freshwater habitats and some have a fossorial lifestyle.Britz, R., Doherty-Bone, T.M., Kouete, M.T., Sykes, D. & Gower, D.J. (2016)''Monopterus luticolus'', a new specie ...

'' until a 2020 study found significant genetic and osteological differences between them and the rest of ''Monopterus'', including unique and highly divergent characteristics in the gill arch skeleton. This led to the species being classified in a new genus ''Rakthamichthys'', with "raktham" meaning "blood-red" in

Malayalam Malayalam (; , ) is a Dravidian language spoken in the Indian state of Kerala and the union territories of Lakshadweep and Puducherry (Mahé district) by the Malayali people. It is one of 22 scheduled languages of India. Malayalam was des ...

, as a reference to their distinctive coloration.

Species

* ''

Rakthamichthys digressus ''Rakthamichthys'' is a genus of swamp eels that are endemic to India. Three species are known from the Western Ghats and one is known from Northeast India. All species live underground, with one species (''R. rongsaw'') having a fossorial l ...

'' (K. C. Gopi, 2002) (blind eel) * ''

Rakthamichthys indicus The Malabar swamp eel (''Rakthamichthys indicus'') (not to be confused with ''Ophichthys fossorius'', also known as the Malabar swampeel) is a species of troglobitic swamp eel endemic to subterranean springs in Kottayam in the Indian state of K ...

'' ( Eapen, 1963) (Malabar blind swamp eel) (=''

Monopterus eapeni The Malabar swamp eel (''Rakthamichthys indicus'') (not to be confused with ''Ophichthys fossorius'', also known as the Malabar swampeel) is a species of troglobitic swamp eel endemic to subterranean springs in Kottayam in the Indian state of K ...

'' Talwar, 1991) * ''

Rakthamichthys mumba ''Rakthamichthys'' is a genus of swamp eels that are endemic to India. Three species are known from the Western Ghats and one is known from Northeast India. All species live underground, with one species (''R. rongsaw'') having a fossorial l ...

'' (Jayasimhan, Thackeray, Mohapatra & Kumar, 2021) * ''

Rakthamichthys rongsaw ''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. Taxonomy It was formerly classified in the genus ''Monop ...

'' ( Britz, D. Sykes, Gower, &

Kamei Kamei ( 亀井, "turtle well") is a Japanese surname. *Japanese clan, Kamei clan People that have the name include: *Akiko Kamei, politician *Eri Kamei, member of Morning Musume *Fumio Kamei, documentary film director *, Japanese fencer * Hirotad ...

, 2018) * ''

Rakthamichthys roseni ''Rakthamichthys'' is a genus of swamp eels that are endemic to India. Three species are known from the Western Ghats and one is known from Northeast India. All species live underground, with one species (''R. rongsaw'') having a fossorial li ...

'' ( R. M. Bailey & Gans, 1998)

References

Cave fish Freshwater fish genera Synbranchidae Freshwater fish of India Taxa named by Ralf Britz Taxa named by Neelesh Dahanukar Taxa named by Rajeev Raghavan {{Rayfinned-fish-stub