Scientists have discovered a new species of freshwater fish in an unnamed stream in the Western Ghats in southern Karnataka and have described their finding as “unexpected” in the latest edition of international taxonomy journal Zootaxa.

The fish, coloured yellowish beige with blue-gray fins and measuring not more than 3 cm, was collected from among tree roots that grew into the edge of the stream flowing off the Barapole tributary of the Valapattanam river and from the thick layers of leaf litter collected in depressions in the river bed.

Researchers have named the fish Dario urops after the Greek words meaning “tail” and “eye” to denote a conspicuous spot near its tail. “This is a significant discovery from a bio-geographic perspective as Dario urops is the first member of the Badidae family that has been described from the Western Ghats,” say the authors. The remaining 19 species within the family are distributed in the rivers of Eastern Himalayas and Indo-Burma, they add.

The research team comprised Ralf Britz from the Natural History Museum, London; Anvar Ali from the Conservation Research Group at St. Albert's College, Kochi; and Siby Philip from the University of Porto, Portugal.

Interestingly, Dario urops was first collected 130 years ago from Wayanad in Kerala by the British Zoologist Francis Day, who, however, did not make a formal description of the species. Ichthyologists, therefore, overlooked the fact that such a species existed.