AmphibiaWeb - Tylototriton notialis
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Tylototriton notialis
Khammouan Crocodile Newt
Subgenus: Yaotriton
family: Salamandridae
subfamily: Pleurodelinae
 
Species Description: Stuart BL, Phimmachak S, Sivongxay N, Robichaud WG 2010 A new species of the Tylototriton asperrimus group (Caudata: Salamandridae) from central Laos. Zootaxa 2650:19-32.
Conservation Status (definitions)
IUCN (Red List) Status Vulnerable (VU)
CITES Appendix II
National Status None
Regional Status Occurs within Nakai-Nam Theun National Protected Area

   

 

View distribution map in BerkeleyMapper.

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 notialis STUART, PHIMMACHAK, SIVONGXAY, & ROBICHAUD 2010
Khammouan crocodile newt

Diagnosis and taxonomy

The holotype of Tylototriton notialis is an adult male (FMNH 271121) collected in Laos, Khammouan Province, Boualapha District, Nakai-Nam Theun National Protected Area, Nam On River catchment, Phou Ak escarpment (17° 38′ 39.6″N, 105° 44′ 12.3″E), at 980 m elevation in 2007. This species is phylogenetically clustered with T. hainanensis and T. ziegleri, but morphologically close to T. panhai (Type III in this study). It is a moderately large species that will grow to a maximum of 13 cm in males and 14.2 cm in females. The population at the type locality in Laos is characterized by the ends of the parotoids, costal nodes, tip and lower side of the tail, fingers and toes, and cloacal region being bright orange and contrasting with the black to brown ground color (similar to the situation in T. lizhenchangi and sometimes in T. asperrimus and T. wenxianensis). This character was not found in the Vietnamese population in Nghe An Province, however. T. notialis is moderately stout, with the head being broader than the body, longer than wide, slightly sloping in profile, and ending in a short snout that is truncated in dorsal view, rounded in profile, with the upper jaw exceeding the lower jaw in length. The nostrils are close to the tip of the snout and slightly visible from above. The vomeropalatine teeth are arranged in two rows, in contact anteriorly and beginning posterior to the anterior margin of the choanae, converging briefly, then diverging from one another. A glandular ridge runs along the midline of the crown from above the anterior edge of the eye to the middle of the head and another along the outer margin of the crown from above the eye to the base of the parotoid. The parotoids are enlarged, projecting backward. A glandular patch of skin is found on the nape. A distinct, tubercular vertebral ridge extends from the posterior end of the crown to the base of the tail, separated from the ridge on the midline of the crown. A dorsolateral row of approximately 14 large glandular warts is present on each side from the level of the axilla to the base of the tail; it is distinctly knob-like anteriorly, becomes smaller posteriorly, and merges at the level of the groin. Smaller glandular warts are found on most of the remaining dorsal and ventral faces, and warts on the crown and nape. The back bears clusters of glands, sometimes these are conical, those on the throat are granular and widely spaced, those on the belly are arranged in strips perpendicular to the body long axis, and a smooth, glandular, ovoid patch of skin exists on the chest. A weak gular fold is present. Four fingers, five toes, all without webbing. The tail is laterally compressed, the dorsal fin narrow, the ventral ridge smooth, and the tip acuminate in profile (STUART et al. 2010). While no subspecies are recognized, significant morphological variation exists between Lao and Vietnamese specimens, the most obvious being that Vietnamese specimens lack the bright orange color on their parotoids.

Distribution

This species is known from only two localities, the type locality Phou Ak, Nakai-Nam Theun National Protected Area in the Nam On River catchment, Phou Ak escarpment, Boualapha District, Khammouan Province, Central Laos, and the Pu Hoat Nature Conservation Reserve and Dong Van Commune, Phong That District in Nghe An Province, Vietnam (YUAN et al. 2010; NISHIKAWA et al. 2013a). The species may also occur at other localities in northern Vietnam and adjacent parts of Laos, however.

Habitat, ethology and ecology

The Khammouan crocodile newt inhabits semi-evergreen forest and open areas with vegetated patches of mixed deciduous and pine forest. I recorded some ecological data during my field survey in 2014: In the Pu Hoat Reserve (Vietnam), the species occurs in the broad-leaved monsoon tropical evergreen forest from 800 to 1,500 m a.s.l.. This type of forest is widespread on mountain sides from the forest block bordering Thanh Hoa and the Chu River to Pu Pha Nha, Pu Cao Ma, Pu Pha Lang and east of Mt. Pu Hoat. Ponds where newts were seen during their breeding season had formed in yellow ferralitic soil with heavily weathered rocks of primarily rhyolite and granite. Dominant plants here were needle-leaved plants such as Nageia fleuryi scattered in a few places and large-leaved trees of the Fagaceae family, Castanopsis seracantha, C. ferox, C. indica, Lithocarpus dussaudi, L. trachycarpa, and Quercus fleuryi. In the Nakai-Nam Theun National Biodiversity Conservation Area, Laos, it lives in the mountainous heart of the area that is made up of block rocks at around 980 to 1,000 m a.s.l.. The reserve receives occasional rains from January through March, but some parts are permanently under water. It is almost always blanketed under clouds and exposed to lengthy phases of light rains or drizzle. At the type locality in Laos, the holotype and larvae were collected between 19.40 and 20.42 h on the sandy and bedrock bottom and depressions filled with leaf litter of a 3 m-wide, slow-flowing stream with a water depth of 10 – 30 cm (pH 5.0; temperature 19.5 ºC), just upstream from a 3 m-high cascade over bedrock. The male paratype was found at 10.30 h, 30 cm above the ground on a 20 cm- diameter log covered by another log, approximately 20 m from a steep escarpment. The type locality lies near the historic Ho Chi Minh Trail, and a large American dud bomb from World War II was embedded in the ground approximately 3 m from the paratype male. The female paratype was likewise found during the day, on the damp forest floor (STUART et al. 2010). The habitat of T. notialis in the Nakai-Nam Theun National Protected Area is characterized by open grassland areas including water bodies and bordered by various species of Dipterocarpus spp., Shorea spp. and species of Myristicaceae, Annonaceae, Rutaceae, Sapindaceae, Fabaceae and others. Terrestrial adults were moving about near a pond. In general, the habitat of this species is very similar to that of T. panhai (Type III) (HERNANDEZ 2016a,b).

Reproduction

Mating takes place in large permanent and semi-permanent pools and ponds that form from the first rains in April/May. The eggs are deposited on the ground in leaf litter near water or in the water. Their development has not yet been observed. The larvae are 20 mm at hatching.

Status, threats and conservation

According to BRYAN STUART (pers. comm.), only 8 specimens are known from the two known localities. This species is therefore considered vulnerable and protected by Laotian law. The locality type in the Nakai-Nam Theun National Biodiversity Conservation Area is fairly sizeable at 3445 km² (the Nam On catchment covers 700 km²), but the newt’s habitats are situated in a degraded and fragmented zone suffering from shift-cultivation by local hilltribes, illegal logging, and Vietnamese poachers frequent this area. In the Pu Hoat Nature Reserve, Nghe An Province, Vietnam, the species seems to be little affected by human activities. It may be vulnerable to illegal collection and use for traditional Chinese medicine like the Laos warty newt (Laotriton laoensis) and the Tam Dao newt (Paramesotriton deloustali), though.

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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 May 2021.

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