New earthworm species adds to Western Ghats’ rich biodiversity

A team of researchers has identified a new earthworm species from the Vazhani dam area of the Peechi-Vazhani Wildlife Sanctuary in Thrissur district of Kerala.

Belonging to the genus Drawida, which is naturally restricted to the south, southeast and east asian region, and the family Moniligastridae, the earthworm has been named Drawida vazhania. The discovery has been published in the peer-reviewed journal Zootaxa.

According to the researchers involved in the discovery, Rajendran Menon Ardra of the Centre for Animal Taxonomy and Ecology under the Department of Zoology, Christ College, Irinjalakuda, and S. Prasanth Narayanan of Advanced Centre of Environmental Studies and Sustainable Development, Mahatma Gandhi University, Kottayam, D. vazhania, with small body size, is a member of the Barwelli species group.

With the description of the new species, the group now comprises seven species. D. vazhania can be easily differentiated from other members of the Barwelli group by the presence of a grooved male genital field, a kidney or bean-shaped prostate, a narrow tubular C-shaped prostatic capsule and a distinct small sessile atrium on the body wall.

India is one of the most earthworm diverse countries in the world, with about 71% of genera and 89% of species endemic to the country. The highest diversity of earthworms in India is found in the Western Ghats and the west coast plains, which together account for roughly 58.4% of all known earthworm species in the country. With the new finding, the total number of Drawida species reported from India and the Western Ghats biodiversity hotspot has risen to 83 and 55 respectively, the researchers said.

Highest number

Among the Western Ghats States, Kerala has the highest number of Drawida species, with 31 recorded so far, including 16 endemic to the State.

Mr. Narayanan said the main issues directly affecting earthworms in the Western Ghats are habitat destruction and transformation. “Kerala’s midlands and coastal lowlands have almost entirely lost their forest cover due to several human activities that have existed since time immemorial. There is practically no remaining protected land in the State’s midlands, except for a few areas of forest cover in the districts of Thrissur, Kollam, and Pathanamthitta,” he said.

Other members of the research team include P. Sunil Kumar, A.V. Sudhikumar and A.P. Thomas.