Researchers detect new species of jumping spider in Rajasthan’s Thar Desert

Mumbai: Researchers have recently documented the presence of a new spider species in Rajasthan’s Thar Desert National Park Wildlife Sanctuary, in addition to a new record of a species for the first time in India.

The species are Pseudomogrus sudhii, named after noted Indian zoologist AV Sudhikumar, which is a newly described species, and Plexippus minor, which has been seen previously only at two locations in the desert landscape of the United Arab Emirates (UAE).

Both species belong to a larger family of ‘jumping spiders’ called ‘salticidae’. The researchers from Christ College, Kerala; Wildlife Institute of India (WII), Dehradun; University of Manchester and the Royal Museum for Central Africa published the findings last week in the international peer-reviewed journal Arachnology.

As per existing literature, the salticidae family contains over 600 different genera (category that ranks above species and below family) and over 6,000 described species of spider, several of which can be found across the country, and more of which are still being discovered. The spiders are called salticidae because instead of trapping prey in a web, it stalks and hunts the prey by pouncing on it.

In 2021, at least three new records of jumping spiders were made in Maharashtra alone, including the species Icius tukarami (named after Tukaram Omble, the police constable who lost his life trying to fend off Ajmal Kasab during the 26/11 terrorist attacks) from Thane-Kalyan, and Phintella cholkei, from Mumbai’s Aarey Colony, named after late naturalist Kamlesh Cholkhe. A third species, Irura mandarina, was recorded in India for the first time, in the Western Ghats, in Sindhudurg district’s Kudal taluka. In the Thar desert, the first recording of another jumping spider species, Menemerus marginatus, was also made in 2021.

Rishikesh Tripathi, who led the research effort to taxonomically describe the Irura mandarina, is one of the researchers behind the recent discoveries from the Thar Desert.

Of the two spiders, the Pseudomogrus sudhii is an entirely new species, belonging to the genus Pseudomogrus which was first described in 1937 and comprises 34 described species of spider distributed across the Canary Islands, the Mediterranean, southern Europe, northern Africa, western Mongolia and western China.

“To date, no Pseudomogrus species from Afghanistan, Pakistan, or India has been recorded or described. Our discovery is the 35th species recorded globally, and the first from India,” said Tripathi.

The Pseudomogrus sudhii was found to occur in the dry arid grasslands of the Thar, and researchers have reason to believe that it is likely that this species may also occur in the Cholistan Desert of Pakistan, which represents the northwestern limit of the Thar Desert. “The salticid faunas of Afghanistan and Pakistan, which beyond doubt should contain Pseudomogrus species (but not recorded yet), remain poorly studied,” the researchers have noted.

The second discovery, of the Plexippus minor from the same geographic region, marks the first sighting of a species previously otherwise seen only at two locations in the Middle East. It belongs to the genus Plexippus, first described in 1846 and which comprises 45 described species to date. Of these, six have been previously found in India.

These discoveries show a strong similarities between the fauna of Palearctic and Oriental zoogeographical regions. The former includes Europe, the region of Asia north of the Himalayas, and Africa north of the Sahara. The latter includes India, Pakistan, Sri Lanka, Bangladesh, Nepal, Bhutan and Burma, Indo-China and southern China.

“Though the regions are biologically distinct, discoveries of similar species shows that there is a biogeographic continuum between them,” said Tripathi.

“For example, most of the closely related species to P. sudhii are known either from the Near East or from the southern Mediterranean and Saudi Arabia. So the presence of a Pseudomogrus species in the Thar Desert suggests a connection in the spider fauna of the region with others in the south Palaearctic. It is hardly surprising because the Thar lies in the transitional zone between the Palaearctic and Oriental Regions,” Tripathi added.

Similarly, the presence of Plexippus minor in the Thar also demonstrates a similar relationship between the two regions. “It’s possible that the Thar region, which is a juxtaposition of environmental conditions found in the Palaearctic, Oriental, and Saharan regions, is supporting a wide array of undiscovered taxa which share a biogeographic relationship across the Middle East and the Indian Thar desert,” said Tripathi.