Assam: Shrub lost 204 years returns; two new fish found in Goalpara wells

Assam Chief Minister Himanta Biswa Sarma on Thursday, October 22, highlighted the return of a shrub unrecorded for 204 years and the discovery of two fish species new to science in village wells in Goalpara district.

The shrub that went missing

The plant is Ardisia colorata, a member of the primrose family. It was first described in 1821 in a gardening periodical, The Botanical Cabinet, according to Kew's Plants of the World Online, and its native range runs from Assam to Myanmar. The Chief Minister said it had been lost for 204 years. As India Today noted, that does not mean it was extinct: a plant can go unrecorded because it was missed, misidentified or growing in forest that nobody surveyed closely.

A blind red loach

The first fish, Gitchak nakana, was described by Ralf Britz and colleagues in the journal Scientific Reports on February 26. It is a tiny bottom-dwelling loach that grows to just 20.8 mm. It has no visible eyes, only a small pigmented spot under the skin, and so little colour that its translucent body looks blood-red. Four pairs of long barbels help it feel its way in the dark.

Its most unusual feature, the paper says, is that its brain is covered only by skin, with no bony skull roof. Its DNA barcode differs by 16.7 to 23.3 per cent from other Asian loaches, and the authors estimate its lineage split from its closest relatives at least 21 to 45 million years ago.

The name comes from Garo: "gitchak" means red, and "nakana" combines the Garo words for fish and blind.

A swamp eel in the same wells

The second species, Rakthamichthys anchi, is a snake-like swamp eel described by Britz and colleagues in Zootaxa on July 30, from wells in the same village. It has more vertebrae ahead of its vent than three related species from the Western Ghats, and its DNA barcode differs from theirs by about 15 to 20 per cent.

Why the wells matter

Both fish live in aquifers, the water-bearing layers of sand and rock underground. According to the Scientific Reports paper, fewer than 10 per cent of the more than 300 known subterranean fish species come from aquifers. The Zootaxa authors describe the alluvial aquifers of north-east India as a previously unknown and highly dynamic habitat.

The researchers did not publish the village's name, to protect the species. The finds were made in an ordinary dug well about 6.7 metres deep, of a kind common across the region.

The Chief Minister's message was that protecting habitats allows species to return.