About five months ago, Vishnu Das, a young graphic designer in a village in Kozhikode district of Kerala, spotted something glistening and slithering in the water in his bathroom at home. When observed closely, he figured that it was a peculiar miniature eel-like species that must have landed in the bathroom via the tap from the water in the well at his home. A fish enthusiast, Das promptly secured the restless eel in a glass and posted a photograph in a local WhatsApp group in pursuit of identification of the species.
Fast forward five months. The specimen that Das caught in his bathroom has proved to be a major breakthrough for ichthyologists in Kerala and across the world. What he caught by accident was a unique, new species of eel-loach that lives in deep subterranean aquifers. The eel, just about 3 centimetres in length and pinkish-red in colour, belongs to the genus Pangio and has been named interestingly as Pangio bhujia, because it resembles the north Indian snack of bhujia.
The species, described by scientists of Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi in a paper in the Zootaxa journal, proves conclusively that certain eel-loaches, till now found in fast-flowing streams of south and southeast Asia, can exist in subterranean conditions as well. The Pangio bhujia is unique because of the absence of the dorsal fin and pelvic fins. It also differs from other species of the Pangio genus due to the presence of long nasal barbels.
“This is an exceptional discovery,” said Rajeev Raghavan, assistant professor at KUFOS, in a statement. In the last one year, Raghavan and his team had discovered two other remarkable subterranean species, mainly through chance encounters as their habitats are difficult to sample through conventional methods.
Anoop VK, a doctoral student at KUFOS and one of the authors of the paper in Zootaxa, is ecstatic over the discovery of such a rare species and doubly thrilled that he was able to be a part of such a moment at an early stage in his career. It was Anoop who chanced upon the photograph of the eel posted by Das on WhatsApp and decided to make the trip to the tiny village of Cherinjal. But even as he knew the eel-loach could be a potential new species, finding more specimens of the same was an arduous task.
“These are subterranean organisms and they are extremely sensitive to light. So finding them was always going to be tough. We went traipsing all over tanks and wells in the neighbourhood, barging into people’s homes to look for the eel. And then somebody said there was a pond nearby that never dries. So we got into it using a giant scoop-net and we got a fully mature specimen. Having got one, we definitely knew there would be others. We ended up with over 15 eel-loaches, complete with their giant eggs,” said Anoop.
Anoop and his colleagues at KUFOS brought the eel-loaches back to the lab in Kochi and began studying them in detail, noting down their unique morphological features, their breeding and feeding habits. They concluded that the Pangio bhujia lives in deep laterite channels of aquifers inside the earth and feeds mainly on plankton and small worms. They have a small set of eyes, as common in other subterranean fishes, along with enhancement of other sensory organs. It is also only the second miniature species in the genus to have up to 20 large eggs in their abdominal cavity, easily visible through the translucent body walls.
“Many of the additional unique and unusual features of Pangio bhujia could also be related to its subterranean life. Its small size and absence of dorsal and pelvic fins and the reduction in the number of fin rays in the pectoral, anal and caudal fins may enable it to move around in even the most confined spaces within the laterite deposits of the aquifers,” the paper underscored.
The presence of Pangio bhujia in certain water spaces, like the one found in Cherinjal village, is also a barometer of a region’s ecological patterns. “It can live only in the purest of water sources and cannot survive in contaminated environs. It is an important indicator of a region’s environmental fragility,” said Anoop.
In the coming months, more studies would be done to determine the species’ evolutionary trajectory and its geographical patterns. At the same time, scientists like Anoop can’t help thank local nature lovers like Das enough for their contributions to research. “If he had flushed the eel down the toilet, like many do, we wouldn’t have possibly discovered this species,” said Anoop, with a smile.