AmphibiaWeb - Tylototriton vietnamensis
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Tylototriton vietnamensis
Vietnamese Crocodile Newt
Subgenus: Yaotriton
family: Salamandridae
subfamily: Pleurodelinae
 
Species Description: Böhme W, Schottler T, Nguyen QT, Köhler J 2005 A new species of salamander, genus Tylototriton (Urodela: Salamandridae), from northern Vietnam. Salamandra 41:213- 220

© 2008 Henk Wallays (1 of 10)
Conservation Status (definitions)
IUCN (Red List) Status Endangered (EN)
CITES Appendix II
National Status None
Regional Status None

   

 

View distribution map in BerkeleyMapper.
View Bd and Bsal data (2 records).

bookcover Account written by Axel Hernandez, author of Crocodile Newts: The Primitive Salamandridae of Asia (Genera Echinotriton and Tylototriton), 2016 Edition Chimaira and may contain excerpts from here. More on the author and book.   

Author: Axel Hernandez

Tylototriton vietnamensis BÖHME, SCHÖTTLER, NGUYEN & KÖHLER 2005
Bac Giang crocodile newt or Vietnamese crocodile newt

Diagnosis and taxonomy

The original description of Tylototriton vietnamensis is based on a male holotype (ZFMK 80637) collected in the vicinity of Dong Vanh Village, Luc His Commune, Luc Nam District, Bac Giang Province, northeastern Vietnam (21°12’N, 106°40’E, approximately 250 - 300 m a.s.l) in June of 2003 and two adult male paratopotypes (ZFMK 82971-972) and three referred topotypic larvae (ZFMK 82973-75) collected in July of 2004 (BÖHME et al. 2005). It is a moderately large species with males that can reach 12.2 cm TL at 8.4 cm SVL. Females are smaller than males with a SVL of 7.5 cm on average (BERNARDES et al. 2011). Sexual dimorphism is poorly expressed. The species is diagnosed by having a relatively stout body, a flattened head that is broader than the body, large and elongated parotoids, dorsal skin that is covered with relatively small warts and glands, three tubercular dorsal ridges, slightly flattened and 11 - 13 moderately developed dorsolateral glandular warts, distinct dorsal and ventral tail fins, a tongue pad with no free posterior margin, a grayish tan or brownish dorsal and tan ventral color, faintly orange tan dorsolateral warts, and a yellow-orange ventral tail fin and tips of fingers and toes. Juveniles exhibit the pale brown to yellowish color of clay (BÖHME et al. 2005).

Distribution

This species is distributed in a restricted area about 20,000 km². Aside from the type locality in the vicinity of Dong Vanh Village, Luc Son Commune, Luc Nam District, Bắc Giang Province, Vietnam, at 250 - 300 m a.s.l. (21°12'N, 106°40'E), other known localities are Son Dong in Bắc Giang Province; Tay Yen Tu Mountain, Uong Bi District, Quang Ninh Province; and Loc Binh District in Lang Son Province. This species probably also occurs in the northern parts of Laos and in southern China (Guangxi Province). Species delimitation in Vietnam is very complicated: According to YUAN et al. (2011) and RAFFAËLLI (2013), this country is home to at least five major populations, but new localities have since been discovered. NISHIKAWA et al. (2013b) and LE et al. (2015) noted that five species exist in this country: T. vietnamensis, T. ziegleri, T. notialis, T. cf. asperrimus (Clade C: Hoa Binh, Lao Cai), and T. anguliceps (probably T. pulcherrimus and T. podichthys), but there are probably more.

Habitat, ethology and ecology

T. vietnamensis appears to be an uncommon species that is found in lowland evergreen forests at between 180 and 580 meters above sea level. It lives near small ponds with long hydroperiods in mixed vegetation of hardwoods, bamboos and shrubs. Although it can tolerate disturbed forest to some extent, this species is dependent on the presence of small muddy ponds in the shadow of trees, and therefore it probably cannot tolerate serious deforestation (NGUYEN QUANG TRUONG pers. comm. 2015). Specimens at the type locality were found in muddy ponds within dense bamboo vegetation in secondary forest. BERNARDES et al. (2013) intensely studied this species in the nature reserve of Tay Yen Tu on the eastern slope of Mount Yen Tu, where they counted 216 specimens between April and July of 2010. Favorable water bodies had a pH above 4.3 and were free of nitrates or nitrites, but many ponds in this area did not harbor any individuals. Males were still aquatic and visible in June and July after the actual breeding season.

Reproduction

The reproductive biology of T. vietnamensis has been little studied in the wild but appears similar to that of T. panhai. Males enter the water first at the beginning of the rainy season and will leave it only in early October. The females will join them only for a very short period, stimulated by the rains of the monsoon. Courtship was not observed. Gravid females were found on the bottom of a dry pond and, on another occasion, were seen depositing their eggs in masses near ponds (THOMAS ZIEGLER pers. comm. 2015). Larvae appear from July and may leave their ponds from the end of summer to October, as is suggested by a larva found in October that measured 4.5 cm TL and seemed close to metamorphosis (BERNARDES et al. 2013). Freshwater crabs appear to be the main predators of larvae and juveniles.

Status, threats and conservation

The small fragmented populations in the north of Vietnam are affected by intensive deforestation, global warming, and erratic rainfalls. This last factor impacts heavily on the breeding ponds, inhibiting both mating and larval development. Populations tend to decline as a result. The largest known population is located in Bac Giang (Lục Nam), but habitat degradation resulting from encroaching agriculture and logging is a major threat here, as it is in Lang Son Province. This species could furthermore be highly susceptible to Batrachochytrium dendrobatidis (THIEN et al. 2013). Collecting for the pet trade or traditional Chinese medicine are probably not the most serious problems at present (NGUYEN QUANG TRUONG pers. comm. 2015). T. vietnamensis is considered “Near Threatened” by the IUCN (2013) and has been protected as per the Vietnam Red Data Book since 2007. The Institute of Ecology and Biological Resources, the Lang Son and Bac Giang Forest Protection Departments, and Cologne Zoo have been collaborating in an ex situ conservation breeding program at the Me Linh Station on the edge of the Tam Dao National Park in Vinh Phuc Province since 2008. Legal protection of habitats and regulation of collecting are significant measures for its conservation.

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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 14 May 2021.

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