Rakthamichthys rongsaw

(Britz, Sykes, Gower and Kamei 2018) Britz, Dahanukar, Standing, Philip, Kumar and Raghavan 2020

Rakthamichthys rongsaw
Monopterus rongsaw. Photograph by Rachunliu G. Kamei and courtesy Ralf Britz


Monopterus rongsaw  Britz, Sykes, Gower and Kamei 2018




Holotype and only known specimen: BNHS FWF 611, 179 mm TL.


Known only from the type locailty: dug from soil at Nongriat Village, Sohra (= Cherrapunji), Khasi Hills, Meghalaya, India (25°14'49.2" N 91°40'1.2" E) 440 m asl.


The original description gives the following details: "The holotype of Monopterus rongsaw was collected during daytime soil-digging searches with bladed hoes for fossorial caecilian amphibians. The specimen was found at a depth of ~ 40 cm in moist, rocky soil in a secondary forest ~ 4 km trekking distance from Double Decker living roots bridge in Nongriat. The specimen was unearthed ~ 50 m from an unnamed stream." (Britz et al. 2018).

Traditionally subterranean biologists have not considered the soil fauna as part of the subterranean realm and they have not studied it. However there are a number of similarities of habitat, especially darkness but also confined space analagous to interstitial habitats, and of evolutionary trajectories such as reduction in eyes and pigment and in body size (Culver and Pipan 2014:128-141). This species and Monopterus luicolus are the only known soil dwelling fishes but there are 35 known species which inhabit the interstitial subterranean environment which is in many ways analagous. Both are shallow, dark and space limited (Culver and Pipan 2014:106-127) and if the two Monopterus species are compared morphologicall to the most exteme interstitial species many similarities can be noted. [See also Culver and Pipan (2008) and Pipan and Culver (2012) for discussions of shallow (or superficial) subterranean habiitats, SSHs].


A member of the 'Amphipnous group' of Monopterus.

Conservation Status


Museum Holdings

As above only.

Key References

Rosen, D. E. and Greenwood, P. H. Journal Article 1976 A fourth neotropical species of synbranchid eel and the phylogeny and systematics of synbranchiform fishes
Ranjit Daniels, R.J. Journal Article 2001 Endemic fishes of the Western Ghats and the Satpura hypothesis
Culver, D.C. and Pipan, T. Journal Article 2008 Superficial subterranean habitats - gateway to the subterranean realm?
Ramanujam, S.N., Manorama, M. and Dey, S. Journal Article 2010 Ichthyodiversity of Meghalaya, India
Britz, R., Lalremsanga, H.T., Lalrotluanga and Lalramliana Journal Article 2011 Monopterus ichthyophoides, a new species of scaled swamp eel (Teleostei: Synbranchiformes: Synbranchidae) from Mizoram, India
Pipan, T. and Culver, D.C. Book Section 2012 Shallow subterranean habitats
Culver, D.C. and Pipan, T Book 2014 Shallow subterranean habitats: Ecology, evolution and conservation
Britz, R., Doherty-Bone, T.M., Kouete, M.T., Sykes, D. and Gower, D.J. Journal Article 2016 Monopterus luticolus, a new species of swamp eel from Cameroon (Teleostei: Synbranchidae)
Varma, A. Book 2017 Groundwater resource and governance in Kerala: status issues and prospects
Britz, R., Sykes, D., Gower, D.J. & Kamei, R.G. Journal Article 2018 Monopterus rongsaw, a new species of hypogean swamp eel from the Khasi Hills in Northeast India (Teleostei: Synbranchiformes: Synbranchidae).
Britz, R., Sudasinghe, H., Sykes, D. and Tharindu Ranasinghe, R.H. Journal Article 2020 Ophichthys desilvai, a poorly known synbranchid eel from Sri Lanka (Teleostei: Synbranchidae)
Britz, R., Dahanukar, N., Standing, A., Philip, S., Kumar, B. amd Raghavan, R. Journal Article 2020 Osteology of ‘Monopterus’ roseni with the description of Rakthamichthys, new genus, and comments on the generic assignment of the Amphipnous Group species (Teleostei: Synbranchiformes).
Hajong, P., Wanlambok Sanglyne, M., Dirborne, C.M., Koch, U. and Ramanujam, P. Journal Article 2021 Diversity and distribution of algae in cave ecosystems of Meghalaya: An overview
Raghavan, R., Britz, R. and Dahanukar, N. Journal Article 2021 Poor groundwater governance threatens ancient subterranean fishes
Vasan, T., Das, P., Varma, V., Tiwari, A., Prakash, A., Manilal, D., Thomas, L., Arjun, C.P., Philip, S., Raghavan, R. and Binoy, V.V. Journal Article 2021 Captivity-induced behaviour and spatial learning abilities in an enigmatic, aquifer-dwelling blind eel, Rakthamichthys digressus
Sengupta, D., Dutt, S., Kharpran Daly, B.D. and Panda, S. Journal Article 2024 Development of Geopark for protecting karst region of Nongkhlieh Area, Meghalaya