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Aenigmachanna mahabali, a new species of troglophilic snakehead (Pisces: Channidae) from Kerala, India

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Abstract

Aenigmachanna mahabali, a new species of troglophilic snakehead is described on the basis of a single specimen recovered from a well in Kerala, India, over 200km south of the type locality for the only known species in the genus. The new species can be distinguished from its congener in possessing fewer dorsal fin rays (53 vs 56-57), fewer total vertebrae (61 vs 64), fewer scales in lateral series (76 vs 83-85) and in the pectoral-fin rays being extended beyond the margin of the membrane into filaments.

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... The family Aenigmachannidae (dragon snakeheads) comprises an ancient 'Gondwanan' lineage within the acanthomorph clade Labyrinthici (Anabantiformes) . Considered 'living fossils', these bizarre snakehead-like fishes are endemic to south-western peninsular India ), from where a single genus, Aenigmachanna, and two species A. gollum and A. mahabali are currently known (Britz et al. 2019;Kumar et al. 2019). Both species have been known only from their original descriptions, and no further information on their distribution, population status or ecology is available. ...
... Both species have been known only from their original descriptions, and no further information on their distribution, population status or ecology is available. While A. gollum was collected from a paddy-field in the village of Oorakam in Malappuram district, Kerala (Britz et al. 2019), A. mahabali was found in a well in the village of Peringara, in Pathanamthitta district, Kerala (Kumar et al. 2019). ...
... The availability of several individuals (and populations) of Aenigmachanna gollum has resulted in a clearer understanding of intraspecific variation in this poorly-known species. The description of Aenigmachanna gollum was based on two specimens (Britz et al. 2019), and that of Aenigmachanna mahabali on a single specimen (Kumar et al. 2019). Both these studies, therefore, could not adequately consider intraspecific variation. ...
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Diversity and distribution of dragon snakeheads of the family Aenigmachannidae, and the identity of Aenigmachanna mahabali
... T HE family Channidae is represented by 53 species in three genera, Channa with 48 valid species distributed from the Middle East to South-East and Far-East Asia, Parachanna with three species restricted to tropical Africa, and Aenigmachanna with two species from the laterite areas of Western Ghats of India (Britz et al., 2019aKumar et al., 2019;Praveenraj et al., 2019a;Sudasinghe et al., 2020aSudasinghe et al., , 2020b. The Eastern Himalayan region possess a remarkable diversity of endemic snakeheads. ...
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... The Western Ghats mountain region is an area with a high level of freshwater fish endemism (Abell et al. 2008) and new species are being described from this part of Peninsular India on a regular basis (Katwate et al. 2014(Katwate et al. , 2018Dahanukar et al. , 2016Britz & Ali 2015;Kumkar et al. 2016;Britz et al. 2018Britz et al. , 2019Kumar et al. 2019). counts were obtained from specimens under transmitted light with the aid of a stereomicroscope. ...
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... Our discovery of Pangio bhujia in the laterite areas of Kerala follows closely that of two other remarkable subterranean fishes, Aenigmachanna gollum (Britz et al. 2019) and A. mahabali (Kumar et al. 2019) raises the number of subterranean fishes from this part of India to ten. Among the species of Pangio, P. bhujia is easily recognized by the absence of both dorsal and pelvic fins and their skeletal supports (basipterygia and dorsal-fin pterygiophores). ...
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  • K K S Babu
  • C K G Nayar
Babu, K.K.S. & Nayar, C.K.G. (2004) A new species of the blind fish horaglanis Menon (Siluroidea: Claridae) from Parappukara (Trichur District) and a new report of horaglanis krishnai Menon from Ettumanur (Kottayam district), Kerala. Journal of the Bombay Natural history Society, 101, 296-299.
The labyrinthici of Ceylon
  • P E P Deraniyagala
Deraniyagala, P.E.P. (1929) The labyrinthici of Ceylon. Spolia Zeylanica, 15, 79-111.
A new synbranchid fish, Monopterus digressus from Kerala, Peninsular India. Records of the Zoological Survey of India
  • K C Gopi
Gopi, K.C. (2002) A new synbranchid fish, Monopterus digressus from Kerala, Peninsular India. Records of the Zoological Survey of India, 100,137-143.
BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT
  • T A Hall
Hall, T.A. (1999) BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. In Nucleic acids symposium series, 41 (41), 95-98.
The structural and drainage patterns of the Western Ghats in the vicinity of the Palghat Gap
  • K Jacob
  • S Narayanaswami
Jacob, K. & Narayanaswami, S. (1954). The structural and drainage patterns of the Western Ghats in the vicinity of the Palghat Gap. Proceedings of the National Institute of Science India, 20 (1), 101-118.
On a remarkable blind siluroid fish of the family Clariidae from Kerala (India). Records of the Indian Museum
  • A G K Menon
Menon, A.G.K. (1950) On a remarkable blind siluroid fish of the family Clariidae from Kerala (India). Records of the Indian Museum, 48 (1), 59-66.
Subterranean fishes of the world. Electronic Version
  • G Proudlove
Proudlove, G. (2019) Subterranean fishes of the world. Electronic Version. Updated 03 May 2019. Available from: https://www. cavefishes.org.uk (accessed 15 May 2019)
Inland fishes of India and adjacent countries
  • P K Talwar
  • A G Jhingran
Talwar, P.K. & Jhingran, A.G. (1991) Inland fishes of India and adjacent countries. Oxford and IBH Publishing Co Pvt Ltd, New Delhi, 1158 pp.
Parachanna nom. nov. for the African snake-heads and rehabilitation of Parachanna insignis (Sauvage,1884) (Pisces, Channidae)
  • G G Teugels
  • J Daget
Teugels, G.G. & Daget, J. (1984) Parachanna nom. nov. for the African snake-heads and rehabilitation of Parachanna insignis (Sauvage,1884) (Pisces, Channidae). Cybium, 8, 1-7.