Vietnamese Knobby Newt – Tylototriton vietnamensis – Böhme, Schöttler, Nguyen & Köhler, 2005

Science name: Tylototriton vietnamensis – Böhme, Schöttler, Nguyen & Köhler, 2005

Taxonomic:  Animalia>> Chordata>> Amphibia>> Caudata >> Salamandridae >> vietnamensis

Species status: Endemic ; IUCN status: VU (Vunerable)

Description: Physical Characteristics:
Tylototriton vietnamensis is a moderately robust newt with males reaching a snout-vent length (SVL) of 48.3–53.6 mm and a total length of 113.9–121.8 mm. It has a broad, slightly sloping head, and a short, truncate snout when viewed from above. The nostrils are positioned near the tip of the snout, and the upper lip is thick and fleshy. The vertebral ridge along the back is formed by small, rounded skin projections, with two additional lateral rows of larger warts running from the forearms to the base of the tail. The dorsal surface is covered with small warts and glands, while the ventral side is almost smooth. Enlarged parotoid glands are present on either side of the head, and the species lacks webbing between its fingers but has basal webbing between its toes.

The tail is laterally compressed, with a well-developed dorsal and ventral tail fin. The larval stage has large, feathery gills, which are absent in adults.

Tylototriton vietnamensis is greyish-tan to brownish in dorsal color, with the ventral side being lighter in color. The rib nodules are tinged orange-tan, and the tips of the fingers and toes are yellow-orange, as is the ventral tail fin.

Distribution and habitat: Altitude:
Tylototriton vietnamensis inhabits elevations ranging from 181 to 980 meters above sea level (asl).

Range:
This species is native to northeastern Vietnam, specifically in Bac Giang, Lang Son, and Quang Ninh provinces. It may also potentially be found in Guangxi Province, China, as similar habitats exist there. The species’ estimated extent of occurrence (EOO) is 6,639 km², encompassing 4-10 threat-defined localities.

Habitat:
Tylototriton vietnamensis is associated with lowland secondary evergreen forests characterized by hardwoods, bamboo, and shrubs. During the breeding season, it is typically found around temporary pools or ponds, particularly those with dense vegetation and relatively long hydroperiods. Outside the breeding season, the species is mostly terrestrial. The forest habitats of this species are at risk of being lost to agricultural expansion, which has led to habitat fragmentation and degradation.

Behaviour and ecology: Lifestyle:
This species is terrestrial outside the breeding season and primarily inhabits forest floors. During the rainy season, it becomes more active and gathers around shallow ponds and pools for breeding. These pools typically form on the forest floor, and the species is sensitive to water quality, being absent in areas with high nitrate concentrations or low pH.

Reproduction:
Tylototriton vietnamensis breeds during the rainy season, laying eggs in water. The species undergoes aquatic larval development, and larvae have been found from June to October in pools and ponds formed by the rainy season. The breeding areas are often densely vegetated, and females lay eggs that develop into larvae, which remain in the water until they metamorphose.

Conservation and status: IUCN Red List Category and Criteria:
Tylototriton vietnamensis is listed as “Vulnerable” on the IUCN Red List under the criteria B1ab(iii,v). The species is vulnerable due to its limited extent of occurrence, its occurrence in only 4-10 threat-defined locations, and ongoing habitat degradation. There is also concern about the collection of individuals for the pet trade and traditional medicine, which contributes to the decline in the number of mature individuals.

Threats:
The major threats to Tylototriton vietnamensis include habitat loss due to deforestation for agriculture and infrastructure development, particularly in lowland forests. The species is also at risk from over-collection for the pet trade and for use in traditional medicine. Additionally, water pollution in breeding areas is a concern.

Conservation Actions:
Conservation efforts for Tylototriton vietnamensis should focus on habitat protection, particularly safeguarding ponds and pools where the species breeds. Some populations occur in protected areas, such as the Tay Yen Tu Nature Reserve, but much of its habitat remains unprotected. Ex situ conservation efforts, such as those conducted by the Cologne Zoo, have been successful in breeding the species in captivity since 2007. Continued efforts are needed to monitor and protect wild populations, as well as to prevent the illegal collection of the species for trade.