More than 100 new frog species have been discovered in India over the last decade alone. One of those is the Kalinga frog (Minevarya Kalinga). Kalinga is a plain-looking brown-colored amphibian that scientists discovered two years ago. The peculiar thing was that they had spotted it in the northern tracts of Eastern Ghats. It’s a hill range that has not seen as many frog discoveries as its western counterpart.
Now the frog has started to appear in the Western Ghats too, in the Uttara Kannada district of Karnataka. It’s more than 1,000 kilometers away from the eastern range. This proves the idea that the Kalinga cricket frog may indeed be distributed across a larger area than what was considered earlier. The slightly larger size of these frogs from its eastern relatives could also signify a new and morphologically distinct “population” of frogs.
Cricket Frogs of Asia
Looks like size, color, and shape, are one of many means to identify a frog. It’s especially true in the case of Asia’s cricket frogs. Cricket frogs (genus Fejervaryal Minervarya) are found across a large part of Asia, including India. Initially, they were confused for pond frogs and were placed in the Genus Rana (Genus: A unit of classification containing organisms that not only have some common traits but also a common ancestor).
A long time ago in 1915, a naturalist found that these frogs in east India, Bangladesh, and adjoining Asian countries, had two distinct lines running down over their pale tummies; these were given their genus named Fejervarya.
But in 2001, the scientist noticed that some small Fejervarya like frogs in Kerala and Karnataka looked a bit different. Apart from the Fejervarya lines on their belly, they also had stark white upper lips, and a small gland called rictal gland near their mouth. So this frog species was assigned a new genus, Minevarya. Another team grouped all South Asian fejervaryans (including Indian species) into another new genus, Zakerana. But this study was still very confusing.
In 2015 a team(including KP Dinesh) used basic generic data to re-classify and rename the genera Minervarya and Zakerana as Fejervarya. In 2018, another team used several fejervaryan frogs genes across 12 Asian countries and reclassified all southeast Asian frogs under genus Fejervarya (including three species in east India that occur here as a part of the Indo-China range), and those in South Asia into the genus Minerraria (all other Indian Fejervarya like frogs now fall in this category)
In 2018, a team including Dinesh stumbled across one from the Eastern Ghats, amidst this fantastical taxonomic melee, scientists have been discovering new species of Minervarya across India. The Kalinga cricket frog (now, Minervarya Kalinga) was found by the team as per the genetic specie which revealed it to be a new species found in some areas in Andhra Pradesh, as well as in many parts of Odisha including the Mahendragiri Hills.
Where else was it found?
The answer to this question has now surfaced to the floor, when Amit Hegde, a doctoral student from Karnatak University along with Dinesh and Girish Kadadevaru (associate professor at Karnatak University) contemplated for amphibians in the shopping bettas (foliage forests) and surrounding agro-forests of Karnataka’s Uttara Kannada district, they came across a “Fejervarya-like” frog.
Hegde recalled that it looked non-identical as compared to the Fejervarya/ Minervarya frogs of the Western Ghats.
The size of the mystery frog was slightly large but resembled the Kalinga cricket frog. These frogs when measured revealed that they were around a centimeter longer than the Kalinga cricket frogs and themselves measured around 5 centimeters. This mystery frog when compared by the team to the specific dimensions with two other cricket frog species found in Uttara Kannada along with the Eastern Ghats Kalinga frogs. These four were clutched neatly as separate units based on morphology unchaperoned.
Is this a New Specie?
Genetics was taken into consideration by Hedge and his colleagues by sequencing a portion of a single gene (16S rRNA) from two of these mystery frogs. The team envisioned this data as a phylogenetic tree and hinged that the mystery frogs assembled under the eastern Kalinga cricket frogs. This gave them a path to conclude that both were the same species i.e. the Kalinga cricket frog.
The author of the study argued in their study published in the journal Zootaxa recently that The mystery frog found here is a “morphologically variable and distinct population” of the species of Kalinga cricket frogs while this not only broadened the distribution of the species to the Western Ghats of India.
Hedge said the variations observed morphologically in the species is a phenomenon where an organism evolves differences in morphology in response to unique local environments which is known as morphological phenotypic plasticity.
Hints of biogeographical inference were provided in their title research study which was titled the “Phenotypic divergence in large-sized cricket frog species that crossed the geographical barriers within peninsular India”, however, it was not additionally clarified.
What Seshadri Commented?
KS Seshadri, amphibian biologist, who was not involved in the study commented that the paper provides only a range extension of the species in an email to Mongabay-India and adding that it doesn’t provide evidence of population-level effects as no microsatellite data are used and no haplotypes are evident from the phylogenetic analysis.
He added that it would be premature to suggest the perceived morphological variation to plasticity based on the study’s small sample size. Seshadri wrote that the findings like this range extension also place the impetus on rigorous science. Adding the point of focus that there is incredible proof highlighting the need for an integrative taxonomic approach that uses multiple, maverick lines of evidence such as morphology, genetic data, and acoustics. He also suggested that examining multiple genes and providing frog call comparisons in the current study could have made a huge difference.
Conservation of Biodiversity?
Seshadri commented that the value of the study is underrated in the present world where science is not valued as much as it should be as it can have huge implications. On the other hand, it can be confusing to the policyholders or managers and infuriating as this may hinder the process of obtaining permits.
Confusion for frog enthusiasts could occur if he wanted to hunt into the intellectual aspects of taxonomy and could lose heart because of this. As a scientist, it is the duty that makes our science free of needless confusion or justifies the stands we take because if we want to conserve species, we need to know which species is ideally found, else it is half lost battle.