Tam Dao Newt – Oreolalax sterlingae – Nguyen, Phung, Le, Ziegler & Böhme, 2013

Science name: Oreolalax sterlingae – Nguyen, Phung, Le, Ziegler & Böhme, 2013

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

Species status: Endemic ; IUCN status: EN (Endangered Species)

Description: Physical Characteristics:
Oreolalax sterlingae is a relatively small species, with males measuring around 37 mm and females 45 mm in snout-vent length. The species has a protruding snout, a hidden tympanum, and elongated parotoid glands. The forelimbs are uniquely enlarged and shorter, with round-tipped fingers that lack webbing. Males possess nuptial spines on their first and second fingers. The skin on the dorsum is covered in round spiny warts, and males have additional spines on their chest.

Coloration:
Live individuals display a brown dorsum with small black spines and a cream-colored venter with brown mottling. Whitish spots appear on the lips and limbs, while yellowish-white spots can be seen on the lower flanks. The tadpoles are black with pale, clear tail fins and a gold stripe along the margins.

Distribution and habitat: Altitude:
Oreolalax sterlingae is found at elevations ranging from 2,345 to 3,108 meters above sea level (asl) in northern Vietnam, particularly in the Hoang Lien Mountain Range.

Range:
This species is known only from Lai Chau and Lao Cai provinces in northern Vietnam. Its extent of occurrence (EOO) is estimated at 639 km², consisting of five or fewer threat-defined locations. Similar habitats and elevations exist in adjacent areas, and further surveys may expand the known range.

Habitat:
Oreolalax sterlingae inhabits upper montane bamboo forests, mixed bamboo and elfin moss forests, and secondary forests with medium and large hardwood trees. The species has been observed near rocky streams and rock crevices, where it relies on forested areas for survival. It prefers areas with heavy rainfall and temperatures ranging from -3°C to 20°C. The species is highly dependent on intact forest environments, and its habitat is in decline due to human activities such as quarrying and agriculture.

Behaviour and ecology: Lifestyle:
Oreolalax sterlingae is typically found near rocky streams in bamboo forests. Its lifestyle is closely linked to water bodies, as tadpoles are aquatic and prefer flowing streams. Adults are observed on rocks near streams, and the species is thought to be forest-dependent, with no observations in disturbed habitats.

Reproduction:
Little is known about the reproductive behavior of O. sterlingae. Tadpoles have been observed in March, and it is assumed that reproduction occurs in streams, as with other species in the genus. Males lack vocal sacs, and no call has been recorded. A paratype female was documented with yellow eggs measuring 3.6 mm in diameter.

Conservation and status: IUCN Red List Category and Criteria:
Oreolalax sterlingae is listed as “Endangered” (B1ab(iii)) due to its limited range, fragmented population, and ongoing habitat degradation. The species was last assessed in 2020.

Threats:
The primary threats to O. sterlingae include habitat degradation from human activities such as tourism, garbage pollution, and construction projects like the cable car system on Mount Fansipan. Additionally, climate change poses a long-term threat to this species, as it relies on stable montane ecosystems that may be affected by rising temperatures and altered precipitation patterns.

Conservation Actions:
While O. sterlingae occurs within the protected areas of Hoang Lien National Park and Bat Xat Nature Reserve, these areas face significant human disturbance. Conservation efforts should focus on minimizing the impact of tourism and preserving intact forest habitats. Further research is needed to assess the species’ population size, trends, and specific ecological needs.