Magadha Burrowing Frog: Resident of Farms

A new species of small burrowing frog has been discovered from the Chota Nagpur plateau in Jharkhand. Scientists have named it ‘Magadha Burrowing Frog,’ (Sphaerotheca magadha) after the ancient kingdom of Magadha in the southern Bihar.

Biologists have described the species using an integrated taxonomic approach that combines molecular analysis, morphology, phylogeny and biogeographic significance of the region. Since the species comes from farm fields, there is a need for more explorations of agro-ecosystems, and not just forests.

This is the first frog discovery from Jharkhand and Bihar in the history of zoological findings, as per literature reviews including a comprehensive online database.

A serendipitous discovery

In June 2015, Vishal Kumar Prasad, the lead author and a researcher with Wildlife Institute of India, Dehradun, was at his home town in Joungi-Nawadih village of Koderma district of Jharkhand. Rains had lashed the place for sometime in the night, and he wanted to take a walk. As he started walking along a road near an agricultural field,  he heard a sound like peee.. peee..peee..

“I had not heard that kind of call,” he said. Curious, he traced the call with a small torch he was carrying. The light funnelled into darkness and he saw the vocal sac of a tiny frog. “I was filled with excitement and curiosity as this tiny frog looked very different from other burrowing frogs (of Sphaerotheca genus),” said Prasad. “After checking more individuals in followings nights surveys, I had a gut feeling that it’s definitely a new species.”

It looked like a juvenile burrowing frog belonging to the Sphaerotheca genus (family: Dicroglossidae). However, its vocal sac indicated that it was an adult frog. Hooked, he continued searching the same area night after night, and was able to record more calling males as well as females.

He then got in touch with K. P. Dinesh, a scientist at the Zoological Survey of India, through B.V. Jadhav, a researcher at Balasaheb Desai College of Patan.

Integrated taxonomic tools and techniques were employed to scientifically describe the species and validate its identity.

With help of collaborators Abhijit Das, a scientist at WII, Priyanka Swamy, a researcher at the Indian Institute of Science, Bengaluru, and Ajinkya Shinde from the Biodiversity Research and Conservation Foundation (BRCF), an NGO working on conservation and research of biodiversity, the researchers have described the frog in a recent study.

Phylogenetic analysis revealed that this frog indeed belonged to the genus Sphaerotheca, which is represented by ten extant species having predominant distribution in India, Sri Lanka, Nepal, Pakistan and Myanmar.

The researchers then compared the available genetic sequences of other species of genus Sphaerotheca from South Asia. Sphaerotheca magadha is most closely related to Sphaerotheca breviceps, a burrowing frog found in the east coast of India, about 1600 km (aerial distance) away.

Members of the genus Sphaerotheca are known to have the distribution in the low to mid elevation landscapes of South Asia. Most of the descriptions are either from homestead areas or from agroecosystems, except for a couple of species described from the mid elevation forests.

The new species, Sphaerotheca magadha has been discovered from 380 m above sea level in agricultural lands of a semi urbanized area of Chota Nagpur Plateau in Jharkhand.

Morphological analysis showed that the frog was the smallest in the genus, and was distinct from other members per a number of criteria such as snout to vent length, head length, tibia length and a unique prominent tarsal tubercle etc.

“The members of genus Sphaerotheca are highly cryptic and most of the discoveries in this group are restricted to either coastal plains or the Western Ghats of India. The discovery of a new species from the eastern plateau and hill regions of India is of great significance,” said Vineeth Kumar. K., Assistant Professor, Department of Zoology, St. Aloysius College at Mangaluru, who was not involved in the research.

Landscapes where the species occur

Urban, agro and forest ecosystems are all parts of a landscape and often studied and mapped for studying landscape ecology, a current thrust area in research. Urban ecosystems are perhaps the most extensively modified part of any landscape. Ecologically sensitive species typically go extinct from such areas, which are often inhabited by human commensal species such as the common toad, black kite, crows, and rats.

Agro-ecosystems are generally dominated by cereal crops or some intermediate monoculture form. Factors such as the use of pesticides, distance from roads, human habitation and other anthropogenic factors may affect what species are found in these areas and their abundances.

“For example, an agro-ecosystem close to forest land will be more likely to support more species of frogs than one close to urban centres. Also, pesticides degrade the ecology of landscape, and lead to loss of diversity and associated deformity in frogs,” said Abhijit Das of WII, Dehradun, one of the co-authors.

Forest is defined as the land with tree crown cover of more than 10 percent and area more than 0.5 ha, according to the Food and Agricultural Organization of United Nations.

However, Das explained that in agro-ecosystems food chains are really simple and often truncated due to their improvised altered biodiversity, unlike in forests.

This latest discovery from an agro-ecosystem flag the issue that proper biodiversity surveys in agro-ecosystems have not been made so far. In a way, the species has adapted itself to the landscape changes but being an amphibian that lays eggs and spends early stages in water, the fate of its population will depend on the threshold of pesticide use and other detrimental human activities.

“I feel that the discovery should be a precursor of future studies on the distribution and population status of this species and its bio-indicator value for agro-system need to be delineated,” said Das.

Dinesh also echoed the urgent necessity of studying agro-ecosystems. “It’s high time we looked for agro-biodiversity and agro-climatic zones-based biodiversity assessments, specifically for amphibians,” he said.

Vineeth Kumar too stressed that “there is a need for increased explorations in the lesser known biogeographic zones of India.”

What’s more, Chota Nagpur plateau is a very old geological formation in India and is mainly formed by Gondwana rock. Hazaribagh range in the Chota Nagpur plateau is the highest open plateau in the region and it abruptly ends in Gangetic plain. Sadly, this plateau is one of the least known biologically.

“There is a need for increased explorations in the lesser known biogeographic zones of India,” said Vineeth Kumar.

CITATION:

Prasad, V. K., Dinesh, K. P., Das, A., Swamy, P., Shinde, A. D., & Vishnu, J. B. (2019). A New Species of Sphaerotheca Gunther, 1859 (Amphibia: Anura: Dicroglossidae) from the Agro Ecosystems of Chota Nagpur Plateau, India. Records of the Zoological Survey of India, 119(3), 197-210.

This story was published in Mongabay India