Nahang Asian Toad – Leptobrachella nahangensis – (Lathrop, Murphy, Orlov & Ho, 1998)

Science name: Leptobrachella nahangensis – (Lathrop, Murphy, Orlov & Ho, 1998)

Taxonomic:  Animalia>> Chordata>> Amphibia>> Anura >> Megophryidae >> nahangensis

Species status: Endemic ; IUCN status: LC (Least Concern)

Description:

Size and Physical Characteristics:
Leptobrachella nahangensis is a relatively large member of the genus, with the holotype male having a snout-vent length of 40.8 mm. Its broad head is nearly as wide as it is long, with a rounded snout. The nostrils are positioned closer to the tip of the snout than the eyes. The species has large eyes, a distinct tympanum, and noticeable supratympanic folds with glands near the shoulders. Its hands and feet are webbed, with ridges on the toes but no lateral fringes. The dorsum is smooth with small pustules and tubercles, and the ventrum is pinkish-white with light mottling.

Coloration in Life:
The dorsum of Leptobrachella nahangensis is brownish-lavender with diffuse dark gray-black spots. The flanks are gray-lavender, covered with dark spots. The limbs and digits show transverse dark bars, and the forearms and heels are yellow-orange. The supratympanic fold is flanked by black, and the tympanum is partially or fully black. The frog has vertical bars on its upper lip, one under the eye and another in the loreal region. The iris is gold with a black reticulated pattern on the upper half.

Coloration in Preservative:
After preservation, the dorsum and sides of the frog appear dark brown-gray, while the limbs are lighter, with transverse bars. The interorbital bar and canthus are dark brown to black. The ventrum is cream-white with subtle mottling, and the femoral glands are white.

Distribution and habitat:

Geographic Range:
Leptobrachella nahangensis is known from a single locality within Ha Nang Nature Reserve, Tuyen Quang Province, northern Vietnam, at an elevation of 314 meters above sea level. This species’ habitat extends into nearby provinces like Ha Giang, Cao Bang, and Bac Kan, where similar environmental conditions exist. Further surveys in these areas may expand the known range of this species.

Elevation:
The species has been recorded at an elevation of 314 meters in its known habitat, a relatively low-elevation environment for members of the genus Leptobrachella.

Area:
As Leptobrachella nahangensis has only been found in a restricted location, the full extent of its range remains uncertain, but similar habitats extend across a broader area in northern Vietnam.

Habitat:
The species is associated with subtropical and tropical moist lowland forests and intermittent streams. The only known individual was observed in a dry, rocky stream bed after a rainstorm, suggesting that it may rely on seasonal water sources for breeding. The frog was found near the entrance of a cave, indicating that it may use both forest floor and rocky stream habitats.

Behaviour and ecology:

Reproductive Biology:
Little is known about the reproductive biology of Leptobrachella nahangensis. However, like other species in the genus, it is presumed to breed in streams, with larval development likely occurring in water. The single observed male was calling from atop a boulder in a stream bed following a rainstorm, indicating that breeding may be linked to seasonal water availability.

Habitat Use:
Leptobrachella nahangensis has been found in forest environments, particularly near rocky, intermittent streams. The species may rely on these temporary water sources during the breeding season and use leaf litter and boulders for shelter outside of breeding periods.

Conservation and status:

IUCN Red List Category and Criteria:
Leptobrachella nahangensis is listed as Data Deficient due to the lack of sufficient information about its distribution, population, and ecology. The species is known from only one location, and more research is required to assess its conservation status accurately.

Population Trend:
The population trend of this species is suspected to be decreasing, primarily due to habitat loss and fragmentation in northern Vietnam.

Threats:
The primary threat to Leptobrachella nahangensis is habitat destruction caused by deforestation and conversion of forest land to agriculture. Northern Vietnam has experienced significant forest loss, and satellite imagery shows cleared land in areas where this species may occur.

Conservation Actions:
Further research is urgently needed to locate additional populations of Leptobrachella nahangensis and gather data on its ecology, distribution, and reproductive biology. Conservation measures should focus on protecting the remaining forest habitats in Ha Nang Nature Reserve and surrounding areas. Efforts to prevent further deforestation and preserve stream habitats will be critical to the species’ survival.