| Aenigmachanna gollum | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Anabantiformes |
| Family: | Aenigmachannidae |
| Genus: | Aenigmachanna |
| Species: | A. gollum |
| Binomial name | |
| Aenigmachanna gollum | |
 | |
Aenigmachanna gollum, the Gollum snakehead, is a species of aquifer-dwelling dragon snakehead fish that is endemic to the Indian state of Kerala. [2]
A. gollum has an elongated, eel-like body coloured mostly brown and beige. Its fins are long and transparent, with the dorsal fin stretching for about three-quarters of its body length, and the anal fin stretching for more than half its body length. Its pectoral fin is large, while the pelvic fin is absent. Its tailfin is ovoid. Several large scales cover the top of the head. It has a reduced swim bladder. [2] [3]
Unlike many stygofauna – which usually have reduced colouring and have poor or no vision – A. gollum has well-developed pigmentation and normally-sized eyes. [2] [4]
Due to its reduced swim bladder, A. gollum cannot remain buoyant in water. [2] Like other snakehead fishes, it breathes air. It moves by undulating its fins, like an eel. [4]
A. gollum is known only from its type locality, a paddy field in Oorakam, Kerala, in the biodiverse Western Ghats; one other occurrence was reported in a well 250 km south of the type locality. [2] Its habitat in subterranean aquifers is threatened by about six million groundwater wells in the region, which lower the water table. [4]
A. gollum is named after the cave-dwelling character Gollum from J. R. R. Tolkien's The Hobbit and The Lord of the Rings book series, as a reference to both A. gollum and Gollum being former surface-dwellers that evolved to adapt to the caves they lived in. [2] [5] [6] The genus Aenigmachanna was raised for the first time on discovery of A. gollum, with aenigma meaning "enigma" in Latin, and Channa being the generic name of Asian snakehead fishes. [2]
A. gollum was the first discovered species of the genus Aenigmachanna. The genus was first placed in the true snakehead fish family Channidae. [2]
A. gollum was placed in a separate genus because of significant physiological and genetic differences between itself and the other genera in Channidae - Parachanna and Channa . A. gollum has an unusually long dorsal fin, anal fin and vertebral column compared to Parachanna and Channa, and also has a more eel-like body. Unlike the other channids, it also lacks pored scales on the lateral line, which normally carry the lateral-line canal, and has more vertebrae lacking ribs. The other channids also have a longer swim bladder. [2] [3] [4]
In 2020, Aenigmachanna was placed in its own monotypic family, the Aenigmachannidae, or the dragon snakeheads. [3] [7]
A. gollum was discovered as a result of the 2018 Kerala floods, when several individuals were washed out of their aquifer habitat and into a paddy field in Oorakam, where they were found and photographed by a resident of the village, who posted the pictures on social media. The pictures were noticed by Rajeev Raghavan from the Kerala University of Fisheries and Ocean Studies, who prompted a study into the species. It was described in 2019. It is the eighth species of fish known from the Kerala aquifers, indicating the presence of a large, hidden ecosystem in the hard-to-study habitat. [5]
Tor is a genus of cyprinid fish commonly known as mahseers.
Channa is a genus of predatory fish in the family Channidae, commonly known as snakeheads, native to freshwater habitats in Asia. This genus contains about 50 scientifically described species. The genus has a wide natural distribution extending from Iraq in the west, to Indonesia and China in the east, and parts of Siberia in the Far East. A particularly high richness of species exists in Myanmar (Burma) and northeastern India, and many Channa species live nowhere else. In contrast, a few widespread species have been introduced to several regions outside their natural range, where they often become invasive. The large and medium-sized Channa species are among the most common staple food fish in several Asian countries, and they are extensively cultured. Apart from their importance as a food fish, snakeheads are consumed in some regions as a traditional medicine for wound healing and reducing postoperative pain and discomfort, and collected for the international aquarium pet trade.
Parachanna is a genus of snakeheads native to freshwater habitats in tropical Africa. Three recognized extant (living) species are in this genus, but a phylogenetic study from 2017 indicates that a fourth, currently undescribed species also exists.
Pangio is a genus of small Asian freshwater fish in the true loach family Cobitidae. In earlier taxonomic schemes it was known as Acanthophthalmus. The "kuhli loach" is well-known in the aquarium trade and commonly identified as P. kuhlii, but most individuals actually appear to be P. semicincta.
The snakeheads are members of the freshwater perciform fish family Channidae, native to parts of Africa and Asia. These elongated, predatory fish are distinguished by their long dorsal fins, large mouths, and shiny teeth. They breathe air with gills, which allows them to migrate short distances over land. They have suprabranchial organs, which are primitive forms of labyrinth organs, that develop when they grow older. The two extant genera are Channa in Asia and Parachanna in Africa, consisting of more than 50 species.
Dwarf snakehead is a term coined by aquarists to describe a group of Channa snakehead fishes growing to about 25 cm (10 in) maximum. They are found in freshwater habitats in South and Southeast Asia, and southern China.
The forest snakehead is a species of snakehead, a fish of the family Channidae. Its range includes most of Southeast Asia and parts of southern China. It lives in forest streams and can reach 40 cm (16 in) in length. The forest snakehead is known in Thai language as pla krasong. Khmer language called it កញ្ជនជៃ, Indonesians named it kehung, while in Malaysia, they called it ikan bujuk in Malay Language and in Vietnamese its name is cá lóc dày
Channa gachua, the dwarf snakehead, is a species of fish in the family Channidae. The name "dwarf snakehead" is also used for several other species of small snakeheads. C. gachua is native to freshwater habitats in southern Asia, where it has a wide distribution from Iran to Indonesia. This fish is considered to be a species complex, a group of several closely related taxa with one name. It is likely at least three to four different species, and further research may differentiate them. A few species such as Channa harcourtbutleri have been separated from the complex in recent decades. The easternmost population of C. gachua is often recognized as a separate species C. limbata, while the isolated Sri Lankan population often is recognized as C. kelaartii.
Channa striata, the striped snakehead, is a species of snakehead fish. It is also known as the common snakehead, chevron snakehead, or snakehead murrel and generally referred simply as mudfish. It is native to South and Southeast Asia, and has been introduced to some Pacific Islands. Reports from Madagascar and Hawaii are misidentifications of C. maculata.
Channoidei is a suborder of fish in the order Anabantiformes. It contains two families: the true snakeheads (Channidae) and the dragon snakeheads (Aenigmachannidae).
The Ceylon snakehead is a species of snakehead found in freshwater habitats, typically shaded streams, in southwestern Sri Lanka.
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.
Channa marulius is a large species of snakehead native to South Asia. Populations in Southeast Asia are now regarded as separate species.
Rajeev Raghavan is a fisheries scientist and aquatic conservation biologist known for his work on the freshwater fishes of the Indian subcontinent. Rajeev is currently an Assistant Professor at the Kerala University of Fisheries and Ocean Studies, Kochi, India, the South Asia Chair of the IUCN’s Freshwater Fish Specialist Group., and the IUCN Freshwater Fish Red List Authority Coordinator for Asia and Oceania.
The Anabantiformes, collectively known as labyrinth fish, are an order of air-breathing freshwater ray-finned fish with two suborders, five families and having at least 207 species. In addition, some authorities expand the order to include the suborder Nandoidei, which includes three families - the Nandidae, Badidae and Pristolepididae - that appear to be closely related to the Anabantiformes. The order, and these three related families, are part of a monophyletic clade which is a sister clade to the Ovalentaria, the other orders in the clade being Synbranchiformes, Carangiformes, Istiophoriformes and Pleuronectiformes. This clade is sometimes referred to as the Carangaria but is left unnamed and unranked in Fishes of the World. This group of fish are found in Asia and Africa, with some species introduced in United States of America.
Channa pulchra is a species of snakehead fish in the family Channidae which is native to Myanmar. It was first described in 2007 by R. Britz from a specimen collected from the Kyeintali Chaung (stream) basin in Rakhine Yoma, western Myanmar. The fish is found in streams that are fast flowing, clear, highly oxygenated and relatively cold (subtropical). It is of little food value but getting popularity as an aquarium fish recently.
Channa royi, the Andaman emerald snakehead, is a species of snakehead fish endemic to the Andaman and Nicobar Islands of India. This dwarf snakehead is distinct from other snakehead species due to its differing coloration, number of vertebrae, and teeth, most notably its greenish-gray dorsum. It was only scientifically described in 2018 and its closest relative is the Burmese snakehead, and a review in 2019 argued that the two are synonyms.
Aenigmachanna is a genus of ray-finned fish in the order Ananbantiformes. It is the only genus in the family Aenigmachannidae, or dragon snakeheads. It contains two species, both of which are largely restricted to subterranean habitats in southwestern India, namely in the Western Ghats foothills in the state of Kerala.
Channa aurolineata is a species of Asian snakehead in the family Channidae. It is found natively in most of Myanmar's waterways as well as the Mae Khlong drainage in Thailand. There is also an invasive population found in Southeast Florida, United States. This species was recently split from C. marulius, the bullseye snakehead, and confirmed as a separate species in 2018; and the Florida and Thailand populations were not discovered to be C. aurolineata until even more recently in 2019. Before this, the Thailand population's species was unknown and the Florida ones were assumed to be C. marulius. C. aurolineata was able to be separated as a new species and identified in other areas due to slight differences in color pattern, lateral line scale and fin ray morphology, and DNA structure from the other species in the marulius complex.
Channa rara is a species of labyrinth fish of the snakehead family (Channidae). It was described in 2019.
