A new species of scorpions from southern India
Students and faculty of the Biology programme discover a species of scorpion in Chikkadunnasandra, Bengaluru
For many of us, scorpions are creatures that live far away, lurking in deserts and the wilderness, or featuring in movies as scary monsters to use their eight legs to devastating effect. We know well to stay away from their claws and venoms if we do chance upon them, and never expect to see them near our safe, urban environments.
What we forget or rather what is less known is that scorpions are very common everywhere. Not only can they be found in every corner of the globe in six of the seven continents in the world, but they can also live in arid deserts, from Chile to the Sahara Desert.
Guess where they were found by our student researchers from our Biology programme in the University: in the dry, leafy environments of Chikkadunnasandra, Bengaluru.
A new species in the backyard of our undergraduate campus
In a scorpion survey led by Shomen Mukherjee with student Malay Pandey, as part of the undergraduate Biology programme, not far from the campus, they chanced upon a species of scorpion in the bark and leaf litter of an Acacia plantation around the village of Chikkadunnasandra. Part of the scorpion genus Isometrus, they had to work on identifying the exact species of the scorpion by comparing it to four other varieties well known in India.
There are four species of the scorpion genus Isometrus in India. They are distributed across the northern Western Ghats of India, some parts of Maharashtra, Karnataka, Tamil Nadu, and Meghalaya. These species – the I. maculatus, I. thurstoni, I. amboli, and I. tamhini, are all to be found in specific rock types, known as “type localities”.
To delimit this species of Isometrus found in the small leafy environment of Chikkadunnasandra, Pandey and Mukherjee studied this species with ‘integrated taxonomy’. This meant looking at this scorpion in comparison with the other ones found in India of the same genus, especially their habitat, environments, and morphologies.
The study began by collecting the scorpions, which involves capturing them using ultraviolet light. Around 9 specimens (7 males and 2 females) were collected and photographed in great detail and preserved in ethanol collection jars. The specimens were then studied with a Leica microscope to understand the morphology, or their size and shape, and structure, especially in comparison with other Isometrus scorpions. The process included statistical and molecular analysis – to determine the classification of the samples and to extract genomic DNA to deposit at the Gen Bank.
The gene sequencing revealed that the species differed from other Indian species by 10 – 16% genetic distance and that its morphology in terms of size and body varied as well. The researchers studied the body and appendages of the scorpion, which was light brownish yellowish, and variegated with blackish brown stripes and spots with occasional dark spots. Its type locality was identified as a dense plantation with tall trees.
Naming the new species after František Kovařík
The researchers also had the privilege of naming the species Isometrus kovariki, with the species epithet honouring František Kovařík, Czech arachnologist, for his remarkable contribution to the scorpion taxonomy of the world.
The new species is known only from one type locality, living in a 10 – 15-year-old Acacia auriculiformis plantation. They are most active in the summer, using the bark of the trees and leaf litter to catch field cockroaches and crickets, and living on trees in the rainy season. Dormant in the winter, they grow active by the end of February and breed in May, and have 12 – 20 progeny.
The specimens collected by the researchers did not match the museum collections of the Isometrus maculatus and Isometrus thurstoni. It is interesting to note that the population of I. kovariki is only found in a small area modified by human activities.
What has intrigued scientists for decades is how these scorpions got where they did, into this type of locality. It could be due to human-mediated transport, or it could be what is known as a cryptic species. Indian fauna is said to have been distributed by the extensive timber trade during British India. With such a restricted population of the new scorpion species, in an area of high disturbance, it definitely needs immediate protection.
This research was published in a new paper called ‘A new species of Isometrus (Scorpiones: Buthidae) from southern India’ in Euscorpius — Occasional Publications in Scorpiology. 2020, No. 310.