New species of blind fish discovered in Meghalaya

A New Zealand-based science journal Zootaxa, published in December 2017, revealed that a new species of blind fish has been discovered inside a cave in East Jaintia Hills district of Meghalaya.

The fish was named as Schistura larketensis. It got its name from Larket village, where the cave has been found, to encourage local people to take up biodiversity conservation.

A team of scientists from the Gauhati University and the North Eastern Hill University jointly studied the fish and concluded that the fish species lost its sight while living in the perpetual darkness inside the cave. The fish lost its pigments too while adapting to its habitat in the dark waters.

The Discovery
• Researchers came across the blind fish in the cave several years ago during an expedition. The cave is about 880 meters above sea level and over 7 km in length.

• The fish sample was collected from small stagnant pools which are of a few square meters in area and about 1-2 metres in depth.

• These pools are about 1600 feet high from the main entrance of the cave. The pool bed is mostly sandy with pebbles.

• Other species found inside the cave were weakly pigmented crabs and crayfish, spiders, crickets, cockroaches, millipedes, small frogs and snakes.

The Findings
• Although there are about 200 known species of similar kind of fish inhabiting streams and rivers throughout Indochina and Southeast Asia, this is the first such discovery of blind fish.

• The new fish species can be immediately distinguished from all other species of Schistura, excluding Schistura papulifera for its vestigial subcutaneous eyes appearing as black spots.

• The orbital diameter of the fish gradually decreases as its matures, with the eyes completely absent in older individuals.

• Small and faintly blackish spot-like depressions appeared in place of eyes, indicating evolutionary and morphological adaptations.

• The researchers point out to the high level of siltation, pollution and acidification in Jaintia Hills due to coal mining and cement plants, which is threatening the cave biodiversity as a whole.

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