Guwahati, Aug 4: How many more fishes are there in the caves of Meghalaya? This question has been at the forefront of everybody’s minds since the discovery of Schistura sonarengaensis .
With India’s longest and deepest caves, the state of Meghalaya is highlighted as among the top caving destinations in the world. A total of 1100 caves have been explored or partially explored, and 537.6 km of cave passage mapped from Meghalaya (based on data from the Meghalaya Adventure Association)
The group of scientists who discovered Schistura sonarengaensis , a new species of cave-dwelling fish from Meghalaya, say the presence of hypogean( subterranean species found in caves) habitats in Meghalaya has been enthralling to the scientific community, an example being the recent discovery of the largest known subterranean troglobitic fish species, Neolissocheilus pnar from Krem Umladaw, East Jaintia Hills, Meghalaya).
“Despite being well renowned for their distinctive underground biodiversity, Meghalaya’s caves have been very little investigated, and the description of S. sonarengaensis sp. nov., including others, points to the fact that there are subterranean populations of undiscovered fish species in these caverns. Thorough surveys will reveal the variety of this exceptional ecosystem and its remarkable fauna, ” the scientists say in their paper.
The scientists say partial exploration of the three caves requires further mapping and study of the subterranean ecosystem as a part of the biodiversity of the region and to address questions relating to evolution and biogeography as well as the richness of the subterranean aquatic diversity and new insights for better conservation and management strategies.
One of the scientists said only 10 caves have been explored from the fishery’s point of view.
WHATS SPECIAL ABOUT KREM SONARENGA : Though the fish species was described from three cave-dwelling populations, it was named after as it was seen first, Krem Sonarenga “As of now, the cave has only one known entrance. The discreet entrance, which is buried among rocks and shrouded in the forest, is narrow and predominantly vertical, with few brief slopping sections. The entrance remains submerged during monsoons and is visible only during winter when the water level is at its lowest. From the main entrance to the sink, it requires goofing around rocks that dry out in the winter. The inner part of the cave is not large enough to allow easy movement within it. The cave was moist, and only dripping water could be observed during winter.
A narrow beam of sunlight was observed in one passage of the cave, but fish were collected from a water pool from a completely dark zone of the cave approximately 900 m away from the main entrance in between rocks. The passage leading to the pool is narrow, and one can not move easily through the passage.
Unlike Krem Sonarenga, Krem Nakama, made of limestone, is located at Nokatgre village, South Garo Hills, Meghalaya. The horizontal entrance has a short, broad opening. A few meters beyond the entrance chamber, there are several passages with large breakdown boulders, some of which are short. Inside, the cave roof is low, with water dripping from it at various places, formation of stalactites and stalagmites, reasonable potential to seasonal changes in water level, and hence significant erosional enlargement is expected.
During the rainy season, the cave receives an enormous influx of running water carrying vegetation such as bamboo, tree branches, and leaf litter. This cave hosts various bats, frogs, and hand-sized spiders, observed in different passages.
Krem Chiabole cave, a few kilometers away from Krem Nakama, can be accessed through a narrow opening hidden under rocks, surrounded by jungle and other vegetation. Large plant roots were seen growing through the roof close to the cave entrance. The cave is characterized by having a large stalactite formation. Inside, the cave was sufficiently large to allow for easy movement, yet some passages were narrow; large breakdown boulders were found in the passages.
Mostly made of rocks, the cave floor also contained patches of bedrock, boulders, and coarse gravel. The detritus on the cave floor, which was made up of forest vegetation like bamboo, tree branches, and leaf litter, is
proof that it is periodically flooded.
Importantly, these caves are devoid of vegetation and probably lack other important primary energy sources, thus depending on allochthonous sources of energy. An allochthonous energy source is a source of energy that originates from outside the ecosystem, such as solar radiation, wind, or water.
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