Description
Tylototriton kachinorum is a medium-sized crocodile newt with a snout to vent length ranging from 72.5 to 84.8 mm for the two described adult female specimens and from 62.3 to 74.1 mm for the seven described adult male specimens. The head is longer than it is wide, and terminates in a long snout that extends slightly past the lower jaw. From a dorsal view, the head is hexagonal, and the snout ends abruptly in a flat tip; however, from a lateral view, the snout is rounded. The snout projects slightly beyond the lower jaw. The nostrils trend further away from the eye and closer toward the anterior tip of the snout, where they cannot be seen from a dorsal view. The labial fold is not present, but the gular fold is. This species has large, semilunar parotoid glands that juts out posteriorly. Extending from the anterior ends of the paratoids to the anterior corner of the orbits are protuberant dorsolateral supratemporal bony ridges. These contrast with the hardly-present sagittal bony ridge. The wide vertebral middorsal ridge begins near the sagittal head ridge and continues down to the first fifth of the tail.The slender body is narrower than the head and covered in fine granules, giving the skin a rough texture. There are no costal folds. Two ridges, composed of 14 glandular warts each, somewhat indistinct rib nodules run longitudinally down the dorsolateral surface of the dorsum. These nodules start out rounded and become sequentially smaller and more elongate as they approach the level of the posterior vent margin, where they terminate. The vent is a longitudinal slit and is situated in a swollen cloacal region. The limbs are also slender, with the hind limbs are marginally longer than the forelimbs. Both pairs of limbs extensively overlap when pressed against the body. The robust fingers and toes are unwebbed. The order of toe length is 4 > 3 > 2 > 5 > 1, while the order of finger length is 3 > 2 > 4 > 1. The tail is longer than the slender body, and is laterally flattened with a pointed tip. There is a somewhat serrated dorsal tail fin that begins from the anterior fifth of the tail and is most prominent at the posterior two thirds of the tail. The hands and feet are finely grooved and lack metatarsal or metacarpal tubercles (Zaw et al. 2019).

A single larval T. kachinorum specimen at larval stage 40 has been described. The snout to vent length is 10.5 mm and the tail length is 9.7 mm. The head is large and trapezoidal in shape, and it has a sloping snout. The nostrils appear at the forward-facing edge of the snout and are small and round. The large, round eyes are located on the sides of the head. The body is highly laterally flattened, and much thinner than the head. The skin is completely smooth. The limbs are thin, and the forelimbs are longer than hind limbs. The forelimbs have 4 well-developed fingers, and the hind limbs have 4 well-developed toes, with a small nub in place of the fifth toe. The tail is nearly as long as the body. The dorsal tail fin originates near the base of the head, while the ventral tail fin originates near the vent. The dorsal tail fin attains its maximum height around the middle of the tail, and the tail tip is sharply pointed. The gills are well-developed and large with distinct fimbriae, and stick up above the rest of the body (Zaw et al. 2019).

There are eight species of Tylototriton in and around Myanmar that are morphologically and phylogenetically similar to the focal species: T. anguliceps, T. himalayanus, T. ngarsuensis, T. podichthys, T. shanjing, T. shanorum, T. uyenoi, and T. verrucosus. Tylototriton kachinorum has weakly distinct rib nodules, while all but T. verrucosus have distinct or very prominent ones. Tylototriton kachinorum differs from T. verrucosus in that its vertebral ridge is continuous and its ground color is brownish while T. verrucosus has a segmented vertebral ridge and a much darker near-black ground color. Tylototriton kachinorum is most morphologically similar to T. himilayanus, its sister species. However T. himilayanus has very distinct lateral grooves on its tail, while T. kachinorum has none whatsoever. Tylotriton kachinorum also has a distinct dark brown coloration with lighter orange-brown and yellow-brown markings which isn’t observed in any other Tylotriton species (Zaw et al. 2019).

In life, T. kachinorum has a fairly uniform dark brown color, which fades into a yellow-brown or orange-brown on the dorsal limb surfaces, paratoids, rib nodules, and vertebral ridge. The ventral side is a dull grayish-yellow color. The rib nodules and the vertebral ridge are yellow-brown to orange-brown. When preserved in ethanol, there was little coloration change besides a gradual desaturation of orange and yellow hues to brownish-grays (Zaw et al. 2019).

Larval T. kachinorum individuals are golden brown in color, and the ventral surface is a pinkish hue. The tail is a dull purple with golden specks, and some dark spots can be seen on the fin and limbs (Zaw et al. 2019).

The nine described adult specimens showed little morphological variation. There is some sexual dimorphism apparent in size, with female specimens being significantly larger and thicker than male specimens. Coloration also varies to a degree, with some specimens appearing lighter or darker overall in comparison to the holotype (Zaw et al. 2019).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Myanmar

View distribution map in BerkeleyMapper.

Tylototriton kachinorum is one of three Tylototriton species known to be endemic to Myanmar. The only known population of T. kachinorum is located on Inying Taung Mountain in the Mohnyin Township of Kachin State. This mountain is a part of the Kachin Hills, which are the southernmost portion of the Himalayas. The species may be more widespread in this region (Zaw et al. 2019).

Tylototriton kachinorum specimens were collected in clearings within montane rainforest habitat between the elevations of 900 and 1050 m (Zaw et al. 2019).

Life History, Abundance, Activity, and Special Behaviors

Extremely little is known about the natural history of Tylototriton kachinorum. The species may be nocturnal, as all adult animals were found at night. Slow-moving aquatic habitats may be favored: specimens were collected from flooded streams and artificial ponds, though local inhabitants also report seeing individuals on dry land far removed from water sources (Zaw et al. 2019).

Tylototriton kachinorum exhibits complete metamorphosis. Courtship behavior in males has been witnessed in the month of July (Zaw et al. 2019).

Although the clutch size of T. kachinorum eggs is unknown, it’s been observed that the eggs are a cream color with a dark brown animal pole (Zaw et al. 2019).

Trends and Threats
The authors of the description propose that T. kachinorum be classified under the IUCN Red List’s “Vulnerable” category. The species distribution may be limited. Furthermore, montane rainforests in Myanmar are being altered and destroyed in tandem with economic development. The actual abundance and population trends of T. kachinorum are unknown (Zaw et al. 2019).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Subtle changes to necessary specialized habitat
Habitat fragmentation

Comments
The phylogeny of T. kachinorum in relation to all 25 other known members of Tylototriton is based off of Bayesian Inference and Maximum Likelihood analyses conducted on partial fragments of ND2 and 16S rRNA mitochondrial DNA. The resulting phylogeny splits Tylototriton into five clades. The clade containing T. kachinorum is composed of species that are distributed across northern and western mainland Southeast Asia, up through the Himalayas, and reaching Yunnan Province in China. The phylogeny also places T. kachinorum as the sister species to T. himalayanus, which is found in Nepal (Zaw et al. 2019).

The species epithet, “kachinorum,” is a Latinized version of the name of the Kachin people who live in the region where the species was first described (Zaw et al. 2019).

References

Zaw, T., Lay, P., Pawangkhanant, P., Gorin, V.A., Poyarkov, N. A. Jr. (2019). "A new species of Crocodile Newt, genus Tylototriton (Amphibia, Caudata, Salamandridae) from the mountains of Kachin State, northern Myanmar." Zoological Research, 40(3), 151-174. [link]

Species Account Citation: AmphibiaWeb 2021 Tylototriton kachinorum: Kachin Crocodile Newt; Kachin Yae Poke Thin <https://amphibiaweb.org/species/8998> University of California, Berkeley, CA, USA. Accessed Jan 24, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 Jan 2025.

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