Latest news with #Neolissochiluspnar
Yahoo
29-05-2025
- General
- Yahoo
Inside the fascinating world of India's blind cave-dwelling fish
Two years ago, zoologist Khlur Baiaineh Mukhim spotted something intriguing in a stream in a remote underground cave in India's north-eastern Meghalaya state. It was a fish he had never seen before, with long barbels - the whisker-like protrusion around a fish's mouth - yellowish-green in colour and, most importantly, with eyes. Cave-dwelling fish, or species of fish that live exclusively in caves, usually don't have eyes, as they have adapted to living in darkness, which is why the fish Mr Mukhim spotted stood out to him. Researchers in Meghalaya now say it is a brand new species of fish, one that has adapted to living above as well as under the ground - a unique characteristic among cave-dwelling species. Their findings were published earlier this month in the latest issue of the Journal of Fish Biology, a leading peer-reviewed publication on fish research. The researchers have named the fish Schistura 'densiclava' after the thick black stripe on its tail. They say that the species is endemic to the cave it was discovered in - Krem Mawjymbuin - in the eastern Khasi Hills, and has been found to exist in both water pools 60m (196ft) deep inside the cave, as well as a nearby stream above ground. Dandadhar Sarma, a professor of zoology and one of the researchers of the study, says that the environment inside the cave is harsh, where temperatures drop to 18C (64.4F) - the ideal temperature for tropical fish to survive is much higher - and oxygen levels are extremely low. "So it's remarkable that the fish can adapt to both - harsh subterranean conditions as well as more favourable surface conditions," Mr Sarma says. Schistura densiclava is the sixth cave-dwelling species of fish that has been discovered in Meghalaya over the past two to three decades, but the only one which has been found to show this ability to adapt to two very different kinds of environments. The state is known to have some of the most complex cave systems in the world but many of its estimated 1,500 to 1,700 limestone and sandstone caves remain unexplored, as they are located in remote, forested regions that are challenging to access. These cave networks are home to numerous animal species that display fascinating evolutionary characteristics but they remain largely unknown because of insufficient research, Mr Sarma says. Over the past five years, a team of researchers from the state, funded by the federal government, have been systematically exploring Meghalaya's vast network of caves to locate and document new species of fish living inside them. In 2019, the research team discovered Neolissochilus pnar, the largest cave-dwelling fish species in the world, Mr Sarma says. The fish was found inside the Krem Umladaw cave in the western Jaintia Hills in a deep pond hundreds of metres below the ground. Mr Mukhim, who is part of the team and has undertaken dozens of cave expeditions, says that cave-dwelling fish display evolutionary traits that are as fascinating as the those displayed by animals living at the Earth's poles or deep inside its oceans. "Cave ecosystems are one of the harshest environments to live in," he says. "These fish usually live in perpetual darkness, stagnant, shallow water pools with dangerously low oxygen levels and sometimes, go for months with little to no food." Nature has helped them survive by doing away with the unwanted and strengthening what's necessary for survival. Consequently, they've lost their eyesight and ability to produce colourful pigments, which would otherwise be a needless waste of energy inside a pitch-dark cave. Instead, they have a sharper sense of taste and smell, and sensory organs on their skin help them detect vibrations to navigate the substrate and avoid predators. Their sources of food include only what's available inside the cave, like leaf debris and marine organisms flushed in by seasonal floods, and even bat excreta. And within this extremely harsh environment, these cave-dwelling fish species live out their lives, some living up to a decade, and even produce offspring. Remarkably, their offspring are born with eyesight - a feature that links them to the surface-dwelling ancestors from which they've evolved - and gradually, they lose their eyesight as they age. But searching for these fish is no easy task. It involves rappelling down hundreds of meters into cavernous holes in the earth, squeezing through tiny tunnels with little oxygen and wading through pools filled with creatures yet unknown in pitch darkness. "Our headlights are the only source of light," Mr Mukhim says. Catching fish involves squatting near pools for hours, and swiftly sweeping up the skittish creatures in a net as they present themselves. Mr Mukhim, who has been studying fish found in the caves of Meghalaya for over a decade, says that there's a need to study these species as that is the only way we will be able to conserve them. "Once a species is wiped out, you can never bring them back," Mr Mukhim says. "It's painful to think that an entire ecosystem in our midst, one of the most fascinating ones, has been studied so little," he adds. "It's time we paid a little more attention to these cave-dwelling marvels of nature." Follow BBC News India on Instagram, YouTube, Twitter and Facebook.
Hindustan Times
26-05-2025
- Science
- Hindustan Times
Cave-dwelling fish that can survive on surface found in Meghalaya
A team of zoologists from Gauhati University, Lady Keane College in Shillong, and the ICAR-National Bureau of Fish Genetic Resources in Lucknow discovered Schistura densiclava — a new species of fish that thrives underground but can adapt to surface conditions as well — in Krem Mawjingbuiñ, a cave in Meghalaya. The limestone cave is located just 15 kilometres from Mawsynram, one of the wettest places on earth. Most hypogean (underground-dwelling) species lose their eyesight and pigmentation over generations, relying on heightened non-visual senses to navigate pitch-dark waters. Unlike them, this unique species of stone loach has eyes and shows off its colours too. Published in the Journal of Fish Biology, a prestigious journal by the Fisheries Society of the British Isles, the discovery has drawn international attention and national applause. Assam's education minister Ranoj Pegu took to social media platform X to congratulate the team, calling it 'a proud moment for Northeast India's scientific community.' With a pale yellow-green body and bold black bars numbering between 14 and 20, the fish sports a distinctive thick stripe near its dorsal fin — the very feature that earned it the species name densiclava, meaning 'dense stripe' in Latin. 'This discovery highlights the untapped biodiversity thriving in Meghalaya's underground ecosystems. It's the ninth new fish species we've described from Northeast India, and the sixth known cave-associated fish from Meghalaya' said Professor Dandadhar Sarma, head of Zoology department at Gauhati University. Unlike fully cave-adapted species such as Schistura papulifera and Neolissochilus pnar — which are pigmentless, blind, and cannot survive in a surface environment— Schistura densiclava thrives inside caves but isn't entirely dependent on subterranean life. Researchers said that the fish was found exclusively in a cool, fast-flowing stream some 60 metres inside the cave, where water temperatures hover at a chilly 18°C and oxygen levels are low. The fish's resilience in such nutrient-scarce conditions is remarkable. Its diet includes copepods, tiny shrimp, insect fragments, and even bat guano. According to Kangkan Sarma, one of the study's lead authors, the species shows clear sexual dimorphism. 'Males are slimmer with irregular patterns and puffier cheeks, while females are more robust and display more uniform markings,' he noted, adding, 'DNA sequencing confirms that this is a genetically distinct species, unlike any other Schistura found in the region.' The East Khasi Hills region, where Krem Mawjingbuiñ lies, is a part of Meghalaya's celebrated cave systems — one of the richest and least explored subterranean landscapes in the world. With over 1,700 caves and cave locations documented, but only a fraction thoroughly studied, Meghalaya is considered a global hotspot for cave biodiversity. 'There were no visible signs of human disturbance inside Krem Mawjingbuiñ,' said one researcher, noting how seasonal access and the surrounding dense forest have kept the cave largely untouched by tourism or ecological isolation, researchers said, is a double-edged sword — protecting species for now, but making them vulnerable to even minor intrusions.
Hindustan Times
25-05-2025
- Science
- Hindustan Times
Schistura Densiclav: New species of cave-dwelling fish found in Meghalaya
A new species of cave-dwelling fish was discovered in Meghalaya's Mawsynram town by a team of researchers from Gauhati University, Lady Keane College in Shillong, and the ICAR-National Bureau of Fish Genetic Resources in Lucknow. The discovery was made in Krem Mawjingbuiñ, a cave located just 15km from Mawsynram beside Sohra (Cherapunji). Despite the cave's remote location and inaccessibility, the team of researchers undertook a challenging expedition that led to the unearthing of this unique species of stone loach. 'This discovery highlights the untapped biodiversity thriving in Meghalaya's underground ecosystems,' said Professor Dandadhar Sarma, Head of the Zoology Department at Gauhati University. 'It's the ninth new fish species we've described from Northeast India, and the sixth known cave-associated fish from Meghalaya.' What makes Schistura Densiclava particularly intriguing is its deviation from the expected evolutionary adaptations of hypogean (underground-dwelling) species. Most cave fish lose their eyesight and pigmentation over generations, relying on heightened non-visual senses to navigate pitch-dark waters. But S. Densiclava still sees — and shows off its colours too. With a pale yellow-green body and bold black bars numbering between 14 and 20, the fish sports a distinctive thick stripe near its dorsal fin — the very feature that earned it the species name densiclava, meaning 'dense stripe' in Latin. Also Read: Scientists discover new species of cricket frog in Western Ghats Published in the Journal of Fish Biology, a prestigious journal by the Fisheries Society of the British Isles, the discovery has earned plaudits from across the world. Assam's education minister Ranoj Pegu took to social media platform X (formerly Twitter) to congratulate the team, calling it 'a proud moment for Northeast India's scientific community.' Unlike fully cave-adapted species such as Schistura papulifera and the ghostly Neolissochilus pnar — which are pigmentless, blind, and highly specialised troglobites — S. Densiclava represents a different evolutionary strategy. It is a troglophile, a species that thrives inside caves but isn't entirely dependent on subterranean life. It retains its vision and pigment, suggesting that it still teeters between two worlds — the surface and the subterranean. Yet field reports suggest S. Densiclava may be shifting further into darkness. It was found exclusively in a cool, fast-flowing stream some 60 metres inside the cave, where water temperatures hover at a chilly 18°C and oxygen levels are low. The fish's resilience in such nutrient-scarce conditions is remarkable. Its diet includes copepods, tiny shrimp, insect fragments, and even bat guano — a feast made possible by the web of interdependence between cave organisms. According to Kangkan Sarma, one of the study's lead authors, the species shows clear sexual dimorphism. 'Males are slimmer with irregular patterns and puffier cheeks, while females are more robust and display more uniform markings,' he noted, adding, 'DNA sequencing confirms that this is a genetically distinct species, unlike any other Schistura found in the region'. The East Khasi Hills region, where Krem Mawjingbuiñ lies, is a part of Meghalaya's celebrated cave systems — one of the richest and least explored subterranean landscapes in the world. With over 1,700 caves and cave locations documented, but only a fraction thoroughly studied, Meghalaya is considered a global hotspot for cave biodiversity. The state's unique karst topography, formed by the slow dissolution of soluble rocks like limestone and dolomite, provides ideal habitats for specialised and often endemic species. The discovery of S. Densiclava adds to a growing list of fascinating finds from Meghalaya's caves. In 1998, Schistura papulifera, another loach from the Siju Cave in South Garo Hills, was the first troglobitic fish to be described from India. More recently, in 2019, researchers stunned the scientific world with the announcement of Neolissochilus pnar, a large blind fish discovered in the Um Ladaw Cave system. With no eyes and no pigmentation, N. Pnar was likened to the 'golden mahseer of the dark.' One of the most striking aspects of the Schistura Densiclava find is the pristine condition of its habitat. 'There were no visible signs of human disturbance inside Krem Mawjingbuiñ,' said one researcher, noting how seasonal access and the surrounding dense forest have kept the cave largely untouched by tourism or development.
