Holotype: ZSI F313/2 38.85mm TL. The description is based on two specimens (second 42.0mm TL) and although the second is not mentioned as a paratype it should be considered as such (also at ZSI). This is the type species by original designation and monotypy of the cave‑restricted genus Horaglanis.
Type locality: A well at an undisclosed location at Kottayam, Kerala, India. Known also from a number of dug out wells in the same area (8o4'N‑10o21'N, 76o13'E‑77o38'E). The type locality of this species is also the type locality of the Synbranchid Monopterus eapeni and at this site at least the two species coexist. It is not known whether they coexist elsewhere.
The only published details are that the fish is found in dug-out wells. It may be an inhabitant of relatively small groundwater voids. Mercy (1981) suggests that they migrate from one well to another through the subsurface drainage system. Francy Kakkasery (pers. comm.) suggests that they live in the water table up to 10m below the surface and that they are only found where laterite is the predominant bed deposit.
The anatomy of H. krishnai has been relatively well studied (see references below) and it seems certain that it is rather different in several ways from other members of the family. Menon (1950, 1951a, 1951b) suggested that the differences were the result of regressive evolution and that the animal was only secondarily primitive. Chardon (1968) made a thorough study of several aspects of siluriform anatomy. He noted that the viscera are more typical of the Bagridae than the Clariidae. This and other evidence suggests that the species is a relict, close to the stem of both Bagridae and Clariidae. Although admitting that there were examples of shared derived characters, and of features associated with hypogean life, Chardon suggested that it is primarily primitive. De Pinna (1998) postulates a relationship between Phreatobius and Horaglanis based on similar skull morphology. A recent photograph of Horaglanis krishnai (Plate 6) shows that it is blood red in colour, a very rare condition for fishes (De Pinna, 1998), as is Phreatobius and this may be a synapomorphy for a group containing the two genera. Clearly there is much to be learned about the exact systematic position of this interesting animal.
(Abraham, R. 2011. Horaglanis krishnai. The IUCN Red List of Threatened Species 2011: http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T10261A3185783.en. Downloaded on 07 July 2017).
R (IUCN, 1990), R (IUCN, 1993), VU D2 (IUCN, 1996, 2000). Dahanukar, Raut and Bhat (2004) assess this species as Critically Endangered but with any explanation of how they arrive at this status.
As above plus: BMNH 1981.11.20:1‑3.
- Menon, A. G. K. (1950)
- Menon, A. G. K. (1951)
- Menon, A. G. K. (1951)
- Eapen, K. C. (1963)
- Chardon, M. (1968)
- Misra, K.S. (1976)
- Mercy, T. V. A. (1981)
- Mercy, T. V. A. (1982)
- Mercy, T. V. A., Padmanabhan, K. G. and Pillai, N. K. (1982)
- Mercy, T. V. A. (1983)
- Mercy, T. V. A., Pillai, N. K. and Balasubramonian, N. K. (1984)
- Mercy, T. V. A. and Pillai, N. K. (1984/5)
- Talwar, P. K. and Jhingran, A. G. (1992)
- de Pinna, M. C. C. (1998)
- Mercy, TVA (2000)
- Mercy, T. V. A. and Pillai, N. K. (2001)
- Mercy, T. V. A., Pillai, N. K. and Balasubramonian, N. K. (2001)
- Dahanukar, N, Raut, R and Bhat, A (2004)
- Subhash Babu, KK and Nayar, CKG (2004)
- Dahanukar, N, Raghavan, R, Ali, A, Abraham, R and Shaji, CP (2011)
- Subhash Babu, KK (2012)
- Raghavan, R., Das, K, Nameer, PO, Bijukumar, A and Dahanukar, N (2016)
- Pavan-Kumar, A (2017)
|Menon, A. G. K.||Journal Article||1950||On a remarkable blind siluroid fish of the family Clariidae from Kerala, (India)|
|Menon, A. G. K.||Journal Article||1951||Distribution of clariid fishes, and its significance in zoogeographical studies|
|Menon, A. G. K.||Journal Article||1951||On certain features in the anatomy of Horaganis Menon|
|Eapen, K. C.||Journal Article||1963||A new species of Monopterus from South India|
|Chardon, M.||Journal Article||1968||Anatomie comparee de l'appareil de Weber et des structures connexes chez les Siluriformes|
|Misra, K.S.||Book Section||1976||Horaglanis krishnai|
|Mercy, T. V. A.||Journal Article||1981||The unique disposition of the valvula cerebelli in Horaglanis krishnai (Teleostei)|
|Mercy, T. V. A.||Journal Article||1982||On the presence of a forked barbel in the blind catfish Horaglanis krishnai Menon|
|Mercy, T. V. A., Padmanabhan, K. G. and Pillai, N. K.||Journal Article||1982||Morphological studies on the oocytes of the blind catfish Horaglanis krishnai Menon|
|Mercy, T. V. A.||Journal Article||1983||Studies on the air bladder of blind clariid Horaglanis krishnai Menon|
|Mercy, T. V. A., Pillai, N. K. and Balasubramonian, N. K.||Journal Article||1984||Studies on the oxygen consumption of the blind catfish Horaglanis krishnai|
|Mercy, T. V. A. and Pillai, N. K.||Journal Article||1984/5||The anatomy and histology of the alimentary tract of the blind cat-fish Horaglanis krishnai|
|Talwar, P. K. and Jhingran, A. G.||Book Section||1992||Genus Horaglanis and species Horaglanis krishnai|
|de Pinna, M. C. C.||Book Section||1998||Phylogenetic relationships of Neotropical Siluriformes (Teleostei: Ostariophysi): Historical overview and synthesis of hypotheses|
|Mercy, TVA||Book Section||2000||Biology of an endemic blind catfish Horaglanis krishnai Menon|
|Mercy, T. V. A. and Pillai, N. K.||Journal Article||2001||Studies on the cranial osteology of the blind catfish Horaglanis krishnai menon (Pisces, Clariidae)|
|Mercy, T. V. A., Pillai, N. K. and Balasubramonian, N. K.||Journal Article||2001||Studies on certain aspects of behaviour in the blind catfish Horaglanis krishnia Menon|
|Dahanukar, N, Raut, R and Bhat, A||Journal Article||2004||Distribution, endemism and threat status of freshwater fishes of the Western Ghats of India|
|Subhash Babu, KK and Nayar, CKG||Journal Article||2004||A new species of the blind fish Horaglanis Menon (Siluroidea: Clariidae) from Parappukara (Trichur District) and a new report of Horaglanis krishnai Menon from Ettumanur (Kottayam District), Kerala|
|Dahanukar, N, Raghavan, R, Ali, A, Abraham, R and Shaji, CP||Book Section||2011||Chapter 3. The status and distribution of freshwater fishes of the Western Ghats|
|Subhash Babu, KK||Journal Article||2012||Horaglanis abdulkalami, a new hypogean blind catfish (Siluriformes: Clariidae) from Kerala, India|
|Raghavan, R., Das, K, Nameer, PO, Bijukumar, A and Dahanukar, N||Journal Article||2016||Protected area and imperriled endemic freshwater biodiversity in the Westren Ghats hotspot|
|Pavan-Kumar, A||Journal Article||2017||Molecular phylogeny of genus Horaglanis (Indian blind catfishes) within Family Clariidae|