AmphibiaChina 中国两栖类.

Description

DESCRIPTION:

Tylototriton broadoridgus is newt found in China. Females are larger than males. The males have snout-vent lengths of 61.1 - 72.6 mm and a total length of 110.4 - 140.3 mm, females have a snout-vent length range of 79.5 - 90.4 mm and a total length range of 138.9 - 162.5 mm. They have a relatively flat, triangle-shaped head that is wider than their body. It has large eyes (about 4.4 mm in diameter) with round eyelids that protrude from the sides of its head. There are ridges on the head that form a V shape with the point on the nose and extending towards its thick neck that has a distinct groove. Tylototriton broadoridgus is mostly recognizable by its vertebral ridge as it is roughly 4.4 mm wide and extends from the base of the neck all the way to the base of the tail. Its hind limbs are longer than its front limbs, and its fingers and toes are flat with round ends. The tail is shorter than the snout-vent length, is laterally compressed, and has strong muscles. The tail fin, when present, is tall and thin, such that the height is greater than the width at the base of the tail. The tail tip is rounded. They have rough skin due to its many warts and tubercles that can be found all over the body, which are grouped together in some places and spread out in others (Shen et al. 2012).

DIAGNOSIS:

Tylototriton broadoridgus has a wider vertebral ridge that is also smoother than similar species. Female T. broadoridgus are larger than females of other Tylotriton species (Qian et al 2017). The rib nodules of T. broadoridgus are distinctly separate from each other, whereas many other species have fused rib nodules (Lyu et al. 2021).

COLORATION:

In life, T. broadoridgus has skin that is dark brown to black highlighted by its orange toe tips, cloacal opening, and stripe on the underside of the tail (Shen et al. 2012).

VARIATION:

Males are smaller on average than females, the former having an average snout-vent length of 66.5 mm and the latter having an average length of 83.3 mm (Shen et al. 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

View distribution map in BerkeleyMapper.

Tylototriton broadoridgus can be found in mountainous regions of Sangzhi county located in the Hunan province of southeastern China, an area that is roughly 999 feet above sea level. Tylototriton broadoridgus, like most salamanders, are primarily found on land, only entering bodies of water, such as ponds, to breed. They prefer to live in areas that have leaf litter and fallen branches such as bamboo forests (Shen et al. 2012).

Life History, Abundance, Activity, and Special Behaviors

Tylototriton broadoridgus breeds in murky and debris-filled ponds that are usually very small (Hernandez 2016).

Juvenile males of T. broadoridgus switch from a terrestrial lifestyle to an aquatic one before other adults of its species. The transition from terrestrial to aquatic lifestyles happens around May and persists for several months to complete the breeding season. Breeding adults may stay in their aquatic form from May all the way to November before returning to a terrestrial lifestyle (Hernandez 2016).

During the breeding season, the species’ already protruding cloacal region grows to bulge even more. Additionally, the female’s abdomens become larger (Shen et al. 2012).

When the adults are finished breeding they forage for food terrestrially but return to the water again afterward (Hernandez 2016).

The species has indirect development, where eggs are laid in ponds and hatch into aquatic larvae. These larvae typically finish metamorphosis before the start of winter, but if they fail to, they may overwinter in ponds, underground, or under leaf litter (Shen et al 2014).

Larva

LARVAL MORPHOLOGY:

A typical larva has a dorsally truncated snout and a large head. Its nostrils are closer to the end of the snout than the eyes. In addition, the forelimbs are longer than the hind limbs (Zaw et al 2019). Larvae show more visible external gills when they reach a size of around 57.8 mm. At 62 mm the gills begin to atrophy as the larvae begin to metamorphosis (Shen et al. 2012).

The larvae rely primarily on tail strength for locomotion as their limbs were observed to be rather weak (Shen et al. 2012).

Trends and Threats
Tylototriton broadoridgus is threatened by habitat destruction. This destruction is primarily in the form of deforestation and the loss of natural pond habitats. The species lacks a large range, something that may cause problems for the population numbers if their range is further reduced by humans (Hernandez 2016).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments

PHYLOGENETIC RELATIONSHIPS:

Based on Maximum Likelihood and Bayesian Inference analyses of ND2 mtDNA, T. broadoridgus is sister to T. dabienicus (Yang et al. 2014, Qian et al. 2017). When T. anhuiensis was described, it became the next most closely related species to the T. broadoridgus and T. dabienicus clade, followed by T. wenxianesis (Qian et al. 2017).

ETYMOLOGY:

The species epithet, “broadoridgus” is a reference to its vertebral ridge being broader than others in its genus (Shen et al. 2012).

References

Hernandez A. (2016). Crocodile Newts - The Primitive Salamandridae from Asia (Genera Echinotriton and Tylototriton). [link]

Lyu, Z.-T., Wang, J., Zeng, Z.-C., Zhou, J.-J., Qi, S., Wan, H., Li, Y.-Y., Wang, Y.-Y. (2021). "A new species of the genus Tylototriton (Caudata, Salamandridae) from Guangdong, southern China, with discussion on the subgenera and species groups within the genus." Vertebrate Zoology 71, 697-710. [link]

Qian, L., Sun, C., Li, J., Guo, W., Pan, T., Kang, X., Wang, H., Jiang, J., Wu, J., Zhang, B. (2017). "A new species of the genus Tylototriton (Amphibia: Urodela: Salamandridae) from the southern Dabie Mountains in Anhui Province." Asian Herpetological Review, 8(3), 151-164. [link]

Shen, Y., Jiang, J., Mo, X. (2012). “A New Species of the Genus Tylototriton (Amphibia, Salamandridae) from Hunan, China.” Asian Herpetological Research, 3(1), 21-30 [link]

Yang, D., Jiang, J., Fei, D. (2014). "A new species of the genus Tylototriton (Urodela: Salamandridae) from Northeastern Hunan Province, China." Asian Herpetological Research, 5(1): 1–11. [link]

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 2023 Tylototriton broadoridgus: Sangzhi Crocodile Newt <https://amphibiaweb.org/species/7859> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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