ROOPAK GOSWAMI
Shillong, Nov 20: A study by a team of Indian and international scientists has led to the rediscovery of two frog species and the description of a new one from community reserves in Meghalaya’s Garo Hills.
Published in Herpetozoa the research illuminates the rich amphibian diversity of the region, which lies in the globally significant Indo-Burma biodiversity hotspot.
The rediscovered species, Raorchestes garo (formerly Ixalus garo) and Raorchestes kempiae (formerly Ixalus kempiae), were last described over a century ago by George Boulenger in 1919. Until now, their status remained ambiguous due to inadequate historical records. Alongside these, a new species, Raorchestes asakgrensis, has been identified, marking a pivotal addition to the scientific understanding of northeastern India’s amphibian fauna.
While Raorchestes garo was found from Daribokgre Community Reserve, Raorchestes kempiae was found from Mikadogre community reserve and Raorchestes asakgrensis was found from Eman Asakgre Community Reserve.
Raorchestes garo and Raorchestes kempiae were identified from specimens collected during extensive field surveys conducted between 2020 and 2022 in the Garo and Khasi Hills. Nocturnal visual encounter surveys were carried out to locate calling individuals of bush frogs.
These nocturnal surveys involved spotting frogs based on their calls, followed by detailed morphological and molecular analysis. The researchers, led by R.S. Naveen and his team from the Sálim Ali Centre for Ornithology and Natural History, reclassified these species into the genus Raorchestes based on their phylogenetic relationships.
The rediscovery of R. garo was particularly remarkable. Found at elevations above 800 meters, the species displays distinct morphological traits, such as an externally visible tympanum and orange-hued hind limbs. Similarly, R. kempiae was found in habitats ranging from 100 to 1,200 meters above sea level, characterized by its concealed tympanum and yellow-spotted ventral coloration.
A New Species from the Garo Hills
The newly described Raorchestes asakgrensis was discovered in the Eman Asakgre Community Reserve. Named after the reserve, this species distinguishes itself with unique features, including an obtusely pointed snout, visible tympanum, and pale cream-colored ventral surface.
The frogs were seen calling at dusk from bushes in and around the Eman Asakgre Community Reserve
Molecular analysis revealed it to be closely related to R. shillongensis and R. garo but with significant genetic divergence.
The discovery highlights the importance of integrative taxonomy, combining genetic, morphological, and ecological data to understand biodiversity. This study bridges a critical gap in the knowledge of northeastern India’s amphibians.
These findings emphasize the urgent need for systematic surveys in biodiversity hotspots. Despite being categorized as Least Concern by the IUCN, R. kempiae has an extensive range, spanning parts of India and China. However, R. garo is limited to an 11.46 sq km area, suggesting a potentially vulnerable status. The researchers call for reassessment of its conservation status and further studies to ascertain its full range.
The study was supported by the National Mission on Himalayan Studies and the Stiftung Artenschutz Amphibian Conservation Fund. It highlights the role of community reserves in protecting biodiversity, as well as the invaluable support of local communities in conservation efforts.
