Team led by DU prof find frog with full leucism, 1st recorded case in India
Researchers led by a Delhi University professor discovered a fully white Indian bullfrog in Uttar Pradesh, the first recorded case in the country.
A team of researchers led by a Delhi University (DU) assistant professor have claimed to have discovered a frog with full leucism (where the individual is fully white), making this the first recorded case in any frog species across the country.
The condition was discovered in an Indian bullfrog (Hoplobatrachus tigerinus) along the banks of the Suheli river in Dudhwa Tiger Reserve, Uttar Pradesh, and the findings have been published in the scientific journal “Herpetology Notes”.
The discovery was made by Robin Suyesh, assistant professor at Sri Venkateswara College, Swastik P Padhy from the ecology, evolution and behavior department, University of Minnesota, and Harshit Chawla from the policy and management studies department at the TERI School of Advanced Studies during a field survey.
According to the journal, the sighting was made on December 3, 2021, and with the individual – identified as an adult frog, completely white, barring its eyes.
“Here, we report on the first case of complete leucism in the Indian bullfrog, Hoplobatrachus tigerinus. The individual exhibited a nearly complete white body, except for the eyes which showed no signs of depigmentation (typical of albinism) and a few discontinuous pigmented bands on the body. Even the tympana were nearly completely without colour,” the research paper, published on July 20 said.
Widespread throughout the Indian subcontinent (Nepal, Bhutan, Bangladesh, Northern Pakistan, and India), the species is generally olive green or yellow and is known for its large size. The frog’s skin colour becomes bright lemon yellow in breeding males and has a light-yellow vertebral streak.
“This is a case of complete leucism and it is the first from India for any frog. The studies on these abnormalities are quite scarce, but such a finding is quite rare,” said Suyesh.
“Mostly, these abnormalities are caused by genetic factors. But sometimes these can also be linked to external factors such as disease, background colour, temperature, moisture, pollution and food availability,” he added. He also said this was not a case of albinism, as the eyes are also impacted in that case.
“Leucism refers to a complete or partial loss of pigmentation except in the eyes and the body margins. In the case of albinism, there is complete absence of pigmentation, which includes the eyes, which appear to be pink or red,” he explained.
Indian bullfrogs can be voracious feeders and have a predominantly carnivorous diet that includes insects, small birds and rodents.
Vineeth Kumar, a zoologist, who has led several studies on frogs across the country, particularly in southern India, said this was a rare occurrence not just in India, but globally too. “Leucism, albinism and melanism are forms of pigmentation and alterations seen among the vertebrates. There are multiple causes for these alterations, which include radiation, genetic mutations and agrochemicals. Amphibians are unique in their lifestyle as they have a dual mode of life and their tadpoles are completely aquatic and these stages are susceptible to the water pollution by agrochemicals,” Kumar said, adding that even as adults, they are highly prone to any disturbances in their environment as they have permeable skin.
“This report of a complete leucistic bullfrog from the Indian subcontinent forms an important ecological observation as it may probe more insights into the probable cause of leucism in one of the most common Indian anuran species,” he said.
Ashish Thomas, assistant professor at Sri Guru Nanak Dev Khalsa College, DU, who too has carried out multiple studies on frogs in the country, said such cases were extremely rare due to the physiological and ecological disadvantages associated with colour loss, stressing the need for greater research in the area.
“Since amphibians are considered as ecological indicators, the occurrence of such an individual in a protected area and genetic and external factors that cause this condition signifies the need for more survey and research in these areas,” he added.