Guwahati: A new species of montane toad has been discovered in Mizoram’s Phawngpui National Park, adding to the growing evidence of previously undocumented amphibian diversity in the state’s high-elevation forests.
The species, named Duttaphrynus phawngpui, was found at about 2,144 metres above sea level in Lawngtlai district and has so far been recorded only from its type locality in the Phawngpui National Park, locally known as Blue Mountain.
The discovery was reported in Taprobanica by a team led by researchers from Mizoram University, along with researchers from Assam Don Bosco University, Indonesia and Help Earth, Guwahati. The authors are Malsawm Dawngliana, Holiness Warjri, A. A. Thasun Amarasinghe, Amit K. Bal, Vanlal Hruaia, Mara D. Hlychho, Hmar T. Lalremsanga, Mathipi Vabeiryureilai and Jayaditya Purkayastha.
Researchers identified the toad using a combination of physical characteristics, statistical analysis of body measurements and mitochondrial DNA. Genetic analysis placed the population within the Duttaphrynus stuarti species group but showed that it forms a distinct evolutionary lineage. Its mitochondrial 16S sequence differed from close relatives by 3.8% to 5.5%, supporting its recognition as a separate species.
The researchers also found a clear separation between the new species and closely related Duttaphrynus species in their morphometric analysis. The first two principal components accounted for 94% of the variation, with the two specimens of the Mizoram lineage forming a distinct cluster from D. stuarti, D. chandai and D. dhara.
The new toad is relatively small, measuring 47.72 to 56.26 mm in snout-to-vent length. It has an indistinct tympanum, lacks most of the cranial ridges found in some related species, has moderate toe webbing and a body covered with glandular warts and irregular dark blotches. A particularly distinctive feature is a thin mid-dorsal stripe running from the snout towards the urostyle.
The toad is described as yellowish-brown to earthy brown, with dark brown to blackish blotches and a narrow cream to pale-yellow stripe along the back. Its underside is cream to pale yellow with dark marbling.
The species was encountered on the forest floor along a trail leading towards the summit of Phawngpui. The specimens were found on leaf litter about 10 metres apart, suggesting a terrestrial lifestyle. Although the observations were made during the day, the researchers said the species is likely to be active during the evening or at night, as with other members of the genus.
Its habitat consists of humid montane forest, dense ground cover, shrubs and bamboo patches, with relatively little human disturbance. The researchers presume that, like other Duttaphrynus species, it feeds mainly on small terrestrial invertebrates, although no feeding behaviour was directly observed during the survey.
The name phawngpui comes from Phawngpui National Park. Researchers have proposed the English vernacular name Phawngpui Toad, with Phawngpui U?awk in Mizo and Phawngpi Utlak in Lai languages.
The discovery also carries a conservation concern. The species is currently known from only one location, and researchers said there is not enough information on its population size, wider distribution or ecological requirements to assess its conservation status.
They have called for further surveys in Phawngpui National Park, southern Mizoram and adjoining upland areas to determine whether Duttaphrynus phawngpui is a narrowly endemic species or occurs more widely.
The researchers noted that high-elevation habitats can act as isolated “sky islands”, encouraging local evolutionary differentiation. At the same time, such species can be particularly vulnerable to climate change because warming temperatures may push them towards higher elevations where suitable habitat could become increasingly limited.
The finding adds another species to the growing list of specialised Duttaphrynus in the Northeast and comes amid increasing evidence that the amphibian diversity of Mizoram and the wider Indo-Burma region remains incompletely documented.