Description

Tylototriton phukhaensis is a crocodile newt from Doi Phu Kha National Park, Nan Province, Thailand. One male and two females were used to describe the species. The snout-vent length for the male is 64.3 mm and for the females they were 68.9 and 70.2 mm. The head length is 25.0 mm for males and for the females was 23.1 mm and 24.8. The snout-vent length is more than double the head length and the head length is slighter greater than the head width. The head is shaped like a hexagon and is longer than it is wide. Tylototriton phukhaensis has a truncated snout from the profile with the nostrils near the snout tip. The head in the profile is concave and somewhat oblique. The snout length is less than half of the lower jaw length. The distance between the eye and nostril is equal to the internarial distance, half of the interorbital distance, and twice the upper-eyelid width. The upper eyelid width is shorter than the orbit length. Tylototriton phukhaensis has a gular fold, but lacks a labial fold. It has rough, slim, protruding dorsolateral bony ridges that begin above the eye and end above the anterior end of the parotoid, which protrudes in the posterior area. These ridges are particularly curved in the middle of the posterior end. The dorsal surface of the head also contains two flat bony ridges that connect to create a “V” shape, which are joined to the prominent and slim sagittal ridge. The ventral side of the head contains many fine granules. There are scattered granules on the throat (Pomchote et al. 2020).

Tylototriton phukhaensis has a slender body and rough skin. The vertebral ridge, which starts at the neck and ends at the base of the tail, is narrow and less prominently segmented, and is not continuous to the sagittal ridge on the head. The 14 - 15 rib nodules on the dorsolateral surfaces extend from the axilla to the base of the tail, look like rounded lump-shaped warts, and are spaced apart from each other in the anterior. The rib nodules increase in size from anterior end to the middle and decrease from the middle to the posterior end, with the fifth nodule as the largest and the most anterior and posterior nodules as the smallest. The granular skin has small, scattered granules. There are many fine granules on the dorsum, sides, and tail, and granules are transversely striated on the mid-ventrum. Tylototriton phukhaensis lacks costal folds (Pomchote et al. 2020).

The forelimbs are a bit longer than the hindlimbs. Males have longer forelimb, hindlimb, and digit lengths than females. The fingers and toes lack webbing and the relative finger lengths are 3 > 2 > 4 > 1. The relative toe lengths are 4 > 3 > 2 > 5 > 1 (Pomchote et al. 2020).

The tail is long, from a lateral view it is fairly flat, and it has a pointed tip. The dorsal fin is more defined in the posterior area. The ventral edge is smooth. The tail length for males is 108.7 mm and for females it is much smaller, ranging from 87.0 - 88.1 mm. The vent length is 10.5 mm for the male, but the length for females is less than half of that for males, ranging from 3.4 - 4.0 mm for females. The basal tail width for males is 10.9 mm and for females it is shorter, ranging from 8.4 - 9.2 mm. The maximum tail width for males is 1.7 mm and for females it is wider, ranging from 2.0 - 2.1 mm. The maximum tail height for males is 8.3 mm and for females it ranges from 8.4 - 8.9 mm. The medial tail height for males is 8.0 mm and for females it is smaller, ranging from 6.9 - 7.5 mm (Pomchote et al. 2020).

Tylototriton phukhaensis is the only Thai Tylototriton with a distinctly large sagittal ridge. Tylototriton phukhaensis is most closely related to T. anguliceps and T. uyenoi. There are no morphometric differences between T. phukhaensis and T. anguliceps, however they have some morphological differences. They can be differentiated based on these characteristics: on T. phukhaensis, the sagittal ridge on the head is slimmer, longer, and straight; the dorsolateral granules are smaller and more thinly dispersed; the coloration of the ventral head, parotoids, vertebral ridge, rib nodules, limbs, vent, and tail ranged from dull red-orange to light brown while for T. anguliceps the color ranges from dark to vivid orange, especially on a section of the ventral trunk (Pomchote et al. 2020).

The size range of T. phukhaensis is smaller than the range of T. uyenoi. Tylototriton phukhaensis had a smaller head width, internarial distance, interorbital distance, orbit length, medial tail width and height, basal tail height, maximum tail height, forelimb length, and hindlimb length. Tylototriton phukhaensis had a larger axilla-groin distance, trunk length, and basal tail width. Tylototriton phukhaensis’ dorsolateral bony ridges are narrower and the posterior end of the ridges are more prominently curved medially than for T. uyenoi. Tylototriton phukhaensis has a narrower, more prominent sagittal ridge and narrower, less segmented vertebral ridge than that of T. uyenoi. Tylototriton phukhaensis has smaller and fewer granules on its skin. Tylototriton phukhaensis does not have as round of a snout as T. uyenoi. Tylototriton phukhaensis has 14 – 15 rib nodules while T. uyenoi has a range of 12 – 16 rib nodules (Pomchote et al. 2020).

Tylototriton phukhaensis and T. verrucosus can be differentiated based on these morphological characteristics: For T. phukhaensis, the head length, head width, interorbital distance, medial tail width, medial tail height, maximum tail height, and hindlimb length are smaller; the trunk length and basal tail width are larger. The vertebral ridge of T. phukaensis is less strongly segmented than that of T. verrucosus. Tylototriton phukhaensis’ dorsolateral bony ridges on the head are rougher and the poster end is more prominently curved medially than T. verrucosus. Tylototriton phukhaensis has 14 – 15 rib nodules while T. verrucosus has a range of 12 – 16 rib nodules. Tylototriton verrucosus and T. phukhaensis have similar color patterns (Pomchote et al. 2020).

Tylototriton phukhaensis is distinct from T. asperrimus and T. taliangensis because T. phukhaensis has head, trunk, limb, and tail markings that range from orange to light brown while T. asperrimus and T. taliangensis are black everywhere except for T. asperrimus’ distal fingers and toes and T. taliangesis’ posterior parotoids. Tylototriton phukhaensis differs from T. kweichowensis because it has an orange marking on each rib nodule while the orange markings on T. kweichowensis create continuous lines. Tylototriton phukhaensis differs from T. shanorum because T. phukhaensis has a sagittal ridge and dorsolateral bony ridges on its head while T. shanorum has no sagittal ridge and flatter dorsolateral bony ridges. Tylototriton phukhaensis has 14 – 15 rib nodules while T. himalayanus has 16 rib nodules and grooves on both sides of its basal tail. Tylototriton phukhaensis differs from T. yangi because T. phukhaensis has orange dorsolateral bony ridges and parotoids on its head while T. yangi has mostly black dorsolateral bony ridges and parotoids. Tylototriton phukhaensis has pectoral and pubic regions with light-orange to light brown coloration, while T. shanjing and T. pulcherrima has a ventral trunk that is yellow-orange to bright yellow in coloration, and T. kachinorum has ventral surfaces that are light yellow-gray. Tylototriton phukhaensis has a long and slim sagittal ridge on its head while T. podichthys’ sagittal ridge is not sharply defined. The vertebral ridge for T. phukhaensis is narrower than that of T. panwaensis (Pomchote et al. 2020).

In life, the dorsal ground is dark-brown and the ventral region is slightly lighter in color. The dorsal and ventral head, parotoids, vertebral ridge, rib nodules, limbs, vent region, and tail range from orange to light brown, while the ventral side of the head, some of the pectoral and pubic regions, limbs, and tail are lighter orange and lighter brown The region that connects the ventral edge of the tail and the vent is lighter in color. In preservation, the colors are faded to a lighter brown than in life (Pomchote et al. 2020).

Relatively, the males have longer tails, vent slits, limbs, and digits than the females. In the three specimens, there was variation in right toe length, in development of the dorsolateral bony ridges on the head, in the prominence of rib nodules, and the shade of the dorsal and ventral head, parotoids, vertebral ridge, rib nodules, limbs, and lateral side of the tail (Pomchote et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Thailand

View distribution map in BerkeleyMapper.

Tylototriton phukhaensis is found in swamp habitat, surrounded by dry evergreen forest, that exists during the raining season in the Doi Dong Ya Wai Mountain, Doi Phu Kha National Park, Nan Province, northern Thailand. The elevation is 1,795 m above mean sea level. The mountain belongs to the Luang Prabang Range, which contains high mountain ranges in Thailand and Laos. The distribution of T. phukhaensis is likely wider than its known location (Pomchote et al. 2020).

Life History, Abundance, Activity, and Special Behaviors

There is little biological data for T. phukhaensis. The specimens were discovered during the time frame of 12.00 - 13.00 in the raining season. Tylototriton phukhaensis’ habitat is a temporary swamp with clear water and dense vegetation at the lowest part of the swamp. The swamp’s pH is 6.4 and its size was 200 m² with a maximum water depth of 11 cm (Pomchote et al. 2020).

Fertilized eggs were found 3 - 82 cm above the water surface, attached to grass tips and a large rock with vegetation. Between one and three eggs are laid in clusters. In the breeding site, the fertilized eggs’ mean diameter fell in the range 5.7 - 12.3 mm. (Pomchote et al. 2020).

Trends and Threats

Tylototriton phukhaensis is threatened by deforestation and other human activities. Villagers living in the surrounding areas of Doi Phu Kha National Park are not prevented from taking forest resources. Illegal hunting is common in the park. Feral cattle grazing in the park also causes damage. Thai National Parks believes that Doi Phu Kha National Park needs better conservation management (Pomchote et al. 2020).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing

Comments

The species authority is: Pomchote, P., Khonsue, W., Thammachoti, P., Hernandez, A., Peerachidacho, P., Suwannapoom, C., Onishi, Y., Nishikawa, K. (2020). “A new species of Tylototriton (Urodela: Salamandridae) from Nan Province, northern Thailand.” Tropical Natural History 20(2): 144-161.

Maximum Likelihood and Bayesian Inference on partial ND2 mtDNA gene sequences were used to determine the relationship among various Tylototriton species. These methods found that T. phukhaensis is a sister species to T. anguliceps and T. uyenoi, but the results are not strong enough to determine how exactly they relate to each other within the clade. The next closest clade contains T. pawaensis, T. podichthys, T. pulcherrima, T. shanjing, and T. verrucosus (Pomchote et al. 2020).

Speciation in the Tylototriton genus originates from geomorphological changes such as climatic changes in Indochina and Indian subcontinent collision that affected northern Thailand (Pomchote et al. 2020).

The species epithet, “phukhaensis”, comes from the name of Doi Phu Kha National Park, which is the type locality of the species (Pomchote et al. 2020).

References

Pomchote, P., Khonsue, W., Thammachoti, P., Hernandez, A., Peerachidacho, P., Suwannapoom, C., Onishi, Y., Nishikawa, K. (2020). ''A new species of Tylototriton (Urodela: Salamandridae) from Nan Province, northern Thailand.'' Tropical Natural History, 20(2), 144-161. [link]

Species Account Citation: AmphibiaWeb 2020 Tylototriton phukhaensis: Doi Phu Kha newt <https://amphibiaweb.org/species/9228> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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