Guwahati: A team of researchers from Gauhati University, Lady Keane College in Shillong, and the ICAR-National Bureau of Fish Genetic Resources in Lucknow has discovered a new species of cave-dwelling fish, Schistura densiclava, in Meghalaya’s Mawsynram town.
The researchers made the discovery of in Krem (cave) Mawjingbuiñ, a cave located 15km from the Mawsynram beside Sohra (Cherapunji).
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Sources indicate that the team undertook a challenging expedition that led to the discovery of this unique species.
This exciting find, detailed through an integrative taxonomy approach, cited the rich biodiversity hidden within the Barak–Surma–Meghna drainage.
The discovery, published in the Journal of Fish Biology (a publication of the Fisheries Society of the British Isles), has received praise from around the world.
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Kangkan Sarma and D. Khlur Baiaineh Mukhim spearheaded as the lead authors of the findings, published in the Journal of Fish Biology.
Other contributors include Hrishikesh Choudhury, Rajdeep Das, Rejani Chandran, Rajeev K. Singh, Deisakee P. Warbah, Wandalin Lyngdoh, Uttam Kumar Sarkar, and Dandadhar Sarma.
According to the journal, a troglophile animal, like Schistura densiclava, is a cave-dwelling creature that can survive and reproduce in environments above ground (epigean).
The researchers found the new stone loach, a bottom-dwelling fish characterized by barbels around its mouth, approximately 60 meters inside the cave. The environment there featured a cool, fast-flowing stream with a temperature of 18°C and low oxygen levels.
Belonging to the Nemacheilidae family, Schistura densiclava shows remarkable adaptation.
Differ from other cave-dwelling fish, Schistura papulifera or Neolissochilus pnar (from Meghalaya), this new species retains full pigmentation and functional eyesight. This indicates its capacity to live in dark subterranean and sunlit surface waters.
The fish has a pale yellow-green body adorned with 14-20 greyish black to faint black bars. It also has a prominent thick stripe near its dorsal fin. This distinctive stripe inspired its name, “densiclava,” meaning “thick stripe” in Latin.
Researchers noted sexual dimorphism in the species. The males are slimmer with irregular patterns and puffier cheeks, and females are sturdier with more consistent markings.
“Genetic testing confirmed it as a completely new species,” the researchers stated.
Analysis of the fish’s mitochondrial cytochrome c oxidase I (COI) gene sequence revealed significant genetic divergence. It has p distances ranging from 4.5% to 13.6% from its closest known relatives in Northeast India.
This genetic evidence strongly supports its classification as a new species.
Notably, Schistura densiclava marks the sixth cave-dwelling fish recorded from Meghalaya. Earlier, scientists from Gauhati University described three of these species.
Following the discovery, Assam Education Minister Ranoj Pegu on his official social media handle X stated, Delighted to learn about the discovery of a new troglophilic loach species, Schistura densiclava (Teleostei: Nemacheilidae), by Kangkan Sarma of the Department of Zoology, Gauhati University, and his team at Krem Mawjumbuin cave in East Khasi Hills, Meghalaya.
“This marks their ninth such discovery, an outstanding testament to their dedication to biodiversity research and a proud moment for the scientific community”, the Minister added.