They have mastered the art of breaking in, stealing and killing the host before retreating with a pirate-like precision.

They are not a gang of marauders on the loose but a pair of new spider species that have recently been discovered in the southern Western Ghats, a biodiversity hotspot, by a team led by a city-based scientist with the Zoological Survey of India (ZSI).

The newly discovered species — Mimetus spinatus and Mimetus parvulus — highlight the importance of this region, said the scientists behind the discovery.

“Both species belong to the spider family Mimetidae, commonly known as pirate or cannibal spiders due to their unique predatory behaviour. These spiders are known for their aggressive mimicry, where they infiltrate the webs of other spiders, mimicking the vibrations of prey or mates to deceive and kill the host spider. Additionally, they exhibit kleptoparasitism, stealing prey and even feeding on the eggs of other spiders,” said Souvik Sen who led the ZSI team that discovered the species.

Sudhin P.P., also from the same organisation, and Pradeep M. Sankaran from Sacred Heart College, Kochi, were the other members.

The addition of two new species brings the number of Mimetus species in India to three, all of which have been spotted in the southern part of the country, they said.

The Mimetus spinatus was collected from Mookambika Wildlife Sanctuary in Udupi district in Karnataka. The Mimetus parvulus was found in Ernakulam, Kerala. The discovery of these new spider species has been published in the August issue of the scientific journal Zootaxa.

“The discovery of these species marks the report of the genus Mimetus after 118 years of the discovery of the last Mimetus species (i.e. Mimetus indicus) from India. This long gap emphasises the need for more extensive surveys into the taxonomy and biogeography of pirate spiders in India,” the ZSI said in a press note.

“The Mimetus spinatus is characterised by its medium size, pale yellow head and dull grey-white abdomen, with scattered light green mottling. It possesses long, black, flattened spine-like hairs on the dorsal head, which inspired its name.

“In contrast, the Mimetus parvulus is distinguished by its pale creamy-rose head with dense grey-black mottling and a triangular-shaped, dull grey-white abdomen covered with numerous tubercles. The species’ name, parvulus, refers to the short copulatory ducts of the female reproductive organ,” it said.

Dhriti Banerjee, director of the ZSI, stressed the importance of the Western Ghats, a Unesco World Heritage site, in preserving India’s rich biodiversity.