What is a semi slug?

• They are kind of snails but their shells are too small to fit them.
• It represents an intermediate stage of evolution, where it’s managed to develop a shell, but it’s far too small to fit its body inside.
• They’re found everywhere, from rainforests to bush, under logs and fallen palm fronds, and even in suburban gardens.

Why in the news?

• aradia amboliensis, a new species of semi-slug, has been found in the Western Ghats by scientists from Shivaji University and others.

• In the new semi-slug, the parts of the mantle(snail’s skin) covering the shell lobes are retractable, so that the shell can be completely covered by the mantle or largely exposed.
• The semi-slug is endemic (found only in certain places) to the northern and central Western Ghats and primarily found in natural forests. It is most active at night and is known from only a handful of localities in Maharashtra, Goa and Karnataka.

Significance of Snails

• Land snails are ecological indicators, they are susceptible to slight climatic fluctuations. 
• They feed on leaf litter present on the forest floor and dead insects. 
• They are the natural source of calcium to the wild animals as they recycle nutrients such as potassium, manganese and magnesium.

References:

1. https://www.thehindu.com/sci-tech/energy-and-environment/western-ghats-record-a-new-to-science-semi-slug/article35059940.ece
2. https://www.australiangeographic.com.au/blogs/creatura-blog/2018/10/meet-the-semi-slug-a-snail-without-a-home/