Researchers find new subterranean catfish species, name it after public

The blind groundwater fish Horaglanis populi is seen in wells near lateritic landscapes and villagers were asked to collect and share details as part of the study. But for the public, the six-year study would not have been possible, say researchers

Researchers have found a new subterranean catfish species in Kerala, Horaglanis populi, a lineage that is the sister group of all currently known species of genus Horaglanis.

Collected from a well in Mallappilli, Kottayam, the tiny fish species is strictly aquifer-residing and does not possess pigment. The scientific paper presenting the result has been published in the international journal Vertebrate Zoology, published from Senckenberg Museum in Germany.

Rajeev Raghavan, Remya L. Sundar, C.P. Arjun, Ralf Britz, and Neelesh Dahanukar are the researchers who carried out the six-year exploratory and citizen-science backed survey to study the diversity, distribution and population structure of Horaglanis.

“With this, the total number of groundwater fish found in Kerala has increased to 12. Horaglanis populi is seen in the wells near lateritic landscapes and apart from Mallappilli, it was spotted at Edanadu, Chengannur, Thiruvanvandoor,” says C.P. Arjun.

The six-year scientific study was conducted using advanced techniques such as demographics, anatomical analysis, and micro-CT. During the survey, the researchers had scoured the lateritic regions of the State while sampling sites included dug-out wells, borewells, natural wetlands adjacent to lateritic zones, home gardens, plantations and lateritic caves. Villagers were made aware of the importance of the study and asked to collect and share information. The species was named Horaglanis populi in honour of the public who cooperated with the researchers during the study.

“In Latin, populi means the people and this would not have been possible without their support as the habitat of the species is mainly restricted to wells,” he adds. Horaglanis populi is blind with a blood-red body and transparent skin. It has a highly reduced pectoral fin and a shortened spine while the dorsal and anal fins are long, extending to the tail.

“ Horaglanis krishnai, H. alikunhii and H. abdulkalami are the three blind catfish seen in Kerala and genetically H.populi forms a distinct clade, the sister group to the other three. Their genetic diversity and distribution was studied for the first time,” he adds.