In April 2018, a strange fish was recovered from a well in the Pathanamthitta district, Kerala. It looked like a snakehead. But locals familiar with snakeheads could not recognise this long reddish-brown fish.
Scientists from the ICAR-National Bureau of Fish Genetic Resources, Kochi took the fish to their lab. They extracted DNA, amplified mitochondrial DNA and compared sequences with those of known snakehead species. As they suspected, the fish turned out to be an entirely new species of snakehead!
Now, scientists who describe new species have the option of naming the species. Rahul G Kumar, Charan Ravi and V S Basheer named it Aenigmachanna mahabali.
So what’s the enigma surrounding the subterranean Aenigmachanna? It’s only found in the Western Ghats! The species is named after Mahabali, a mythological king banished to the netherworld by Vamana, the fifth incarnation of Vishnu. However, Vishnu allowed Mahabali to visit his people only once every year in Autumn. But Aenigmachanna mahabali appeared in April, surfacing in the well from its subterranean abode, having followed subterranean aquatic caverns and ducts.
A few months later, the August 2018 floods in Kerala connected subterranean waters with surface waters. And another new fish was discovered by a fish enthusiast in a paddy field in Malappuram district. A team of researchers from the Kerala University of Fisheries and Ocean studies and IISER Pune described that snakehead fish and called it Aenigmachanna gollum, after a character in Tolkien’s The Lord of the Rings.
The new fish from Pathanamthitta is similar to it in many respects but differed in some others: it had a shorter head, longer upper jaw and smaller eyes, fewer dorsal fins and scales.
The discovery of the two new species of snakehead fish, far removed from each other, in Pathanamthitta and Malappuram, is testimony to Kerala’s biodiversity. Eight species from four genera and four families were first found here. According to the scientists, the discovery of new subterranean fish species has increased rapidly. In 2000, there were only 103 known species. Now there are almost 250. More remain to be discovered, say the scientists.
This year’s floods may throw up more such unusual fish, making Kerala alluring to citizen scientists looking for new species.
Zootaxa 4638 (3): 410–418 (2019):