ZSI scientists discover a wolf spider, and four wasp species from West Bengal

The Hindu

4 days ago

Scientists from the Zoological Survey of India (ZSI) have announced the discovery of a new species of wolf spider, and four new species of spider-egg parasitic wasps, all from the State of West Bengal in the month of July.
The newly described spider, Piratula acuminata, marks the first record of the genus Piratula in India. Discovered on Sagar island, part of the ecologically sensitive Sundarbans delta, this ground-dwelling wolf spider belongs to the family Lycosidae, commonly known as wolf spiders. Agile and nocturnal, they do not weave webs but ambush prey with precision and speed.
'This is a medium-sized spider, roughly eight to 10 millimetres in length,' Souvik Sen, lead author of the study from the ZSI, Kolkata, said. The details of the study have been published in the international peer reviewed journal Zootaxa, under the title 'First record of the genus Piratula Roewer, 1960from India, with the description of a new species'.
The species is distinguished by a creamy-white body interspersed with brown and chalk-white spots, and unique genital structures. 'The unique morphological features of this spider immediately indicated it was an undocumented species,' Dr. Sen said, adding that the team of researchers conducted extensive morphological analysis over several weeks to confirm the findings.
Along with Dr. Sen, Sudhin P.P. of the ZSI worked on the discovery, in collaboration with Pradeep M. Sankaran from Sacred Heart College, Kochi. The spider species was found in the estuarine mudflats of Sagar island, an area shaped by the river Ganga's alluvial deposits, and renowned for its high yet largely untapped biodiversity.
Earlier this month in a separate study ZSI researchers led by K. Rajmohana identified and described four new species of parasitoid wasps belonging to the genus Idris (Hymenoptera: Scelionidae). These tiny wasps — Idris bianor, Idris furvus, Idris hyllus, and Idris longiscapus — were collected from agroecosystems and semi-natural habitats across West Bengal between 2021 and 2023.
These wasps, no more than a few millimetres long, are primary egg parasitoids of jumping spiders (Salticidae), and exhibit an unusual behaviour known as gregarious parasitism, where multiple wasps emerge from a single spider egg sac.
'This work underscores how much remains hidden in our own backyards,' said Dr. Rajmohana, Scientist E at the ZSI, whose team combined classical morphological taxonomy with DNA barcoding to confirm the presence of a new species. The findings were published recently in the European Journal of Taxonomy in a paper titled Description of four new species of Idris Forsters, 1856 ( Hymenoptera : Scelioniadate) India
'This integrative approach is now essential for accurate species delimitation, especially in micro-fauna where physical differences are minimal,' K.P. Dinesh from ZSI Pune, co-author of the paper, said.
Parasitoid wasps like Idris play a key role in regulating spider populations and maintaining arthropod community balance.
'These discoveries reaffirm the significance of systematic taxonomy and modern molecular tools in uncovering India's hidden biodiversity. They also strengthen our national mission to document life forms before they are lost to climate change and habitat degradation,' lauding the teams for these discoveries, Dhriti Banerjee, Director, ZSI, said.
While the specimens of Piratula acuminata were collected exclusively from Sagar island, the Idris wasps were gathered from multiple districts across West Bengal, pointing to both the ecological specificity and the wide-ranging diversity harboured by these regions.