AmphibiaChina 中国两栖类.

Description
Pachytriton xanthospilos is a moderate-sized, sturdily-built bodied newt with a total length reaching over 150 mm and a snout-vent length of around 82.6 mm. They have a long, flat head, which can be rectangular or oval in shape. The trimmed snout just barely extends past the mandible, and the nostrils are at the tip of the snout. The eyes are small. They have a prominent parotid gland. They have short limbs that don’t touch when adpressed to the body. They have four fingers and five toes with minimal webbing present. The relative finger lengths are 1 < 4 < 2 < 3 and the relative toe lengths are 1 < 5 < 2 < 4 < 3. The tail is laterally compressed with an obvious dorsal fin that expands from the base of the tail to the tip and an obvious ventral fin (Wu et al. 2012).

DIAGNOSIS:

Pachytriton xanthospilos has a more robust body than P. feii and longer limbs than P. brevipes (Wu et al. 2012).

COLORATION:

In life, most P. xanthospilos have uniformly light brown dorsums with large dorsolateral orange splotches. However, some individuals may appear as darker shades of brown or predominantly orange in color. Orange splotches may also be present on the head. In preservative, P. xanthospilos' brown dorsum darkens but may be lighter on the head. The tail has a thin pale gold edge on the dorsal fin. The orange splotches become yellowish-gold from head to vent, which is lighter near the head and grows darker near the belly. The ventral side of the tail has a solid pale gold stripe. Juveniles present the same coloration as adults (Wu et al. 2012).

VARIATION:

Males P. xanthospilos have larger and mildly swollen cloacas with papillae lining the walls. Juveniles have a larger tongue than adults, suggesting possible different diets. Variation in overall body color is also present with dorsolateral spots varying in size from small to large, and ventral coloration ranging from brown with orange blotches to completely orange. The edges of the ventral blotches are more defined in smaller individuals and more diffuse in larger individuals (Wu et al 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

View distribution map in BerkeleyMapper.

Pachytriton xanthospilos is found in the Nanling Mountain Range of southeastern China. This species is found on Mt. Mang, located in the Mangshan National Forest Park along the Guangdong and Hunan province border. While P. xanthospilos has so far only been found on Mt. Mang, it is expected that they are also present in the nearby mountains of the Guangdong Nanling National Forest. These salamanders live in elevations 800 - 1400 meters above sea level and are highly aquatic. They live in montane streams surrounded and covered by very dense vegetation, consisting of broad-leaf trees, bushes, bamboo, and tall grasses (Wu et al. 2012, IUCN 2020).

Life History, Abundance, Activity, and Special Behaviors
Pachytriton xanthospilos is a nocturnal and highly aquatic species, indicated by its characteristic paddle-shaped tail. They spend most of their time in pools along montane streams and rest at the bottom of them in the daytime. These streams carry cold and clear water and are around 2 - 3 meters wide and 0.5 - 1 meter deep. The stream-side pools they spend most of their time in are slow moving and have stream beds composed of large rocks, gravel, sand, and fallen leaves (Wu et al. 2012).

Pachytriton xanthospilos lives in sympatry with the tadpoles of Leptobrachium liui (Wu et al. 2012).

The breeding season is unknown in P. xanthospilos, although in the closely related species P. feii, which lives in a very similar habitat to P. xanthospilos, it is postulated to occur between late spring and early summer (Nishikawa et al. 2011). This may also be the case for P. xanthospilos.

Trends and Threats
Pachytriton xanthospilos is listed as “Critically Endangered” by the IUCN as their population size is decreasing. This species' most prominent threats are habitat loss, trapping, and climate change. Tourism has resulted in destruction of the habitat this species lives in (IUCN 2020). Humans also illegally collected Pachytriton species, including species P. xanthospilos, for the pet trade (Wu et al. 2012, IUCN 2020). This results in mature individuals being removed from an already declining population. Climate change has a negative impact on the genus as a whole, as it disrupts the monsoon season. However, P. xanthospilos may be less at risk because it occurs at a broad range of elevations. Climate change may also cause the species to experience extreme droughts and hot temperatures. Pachytriton xanthospilos is found within protected land in China, that being the Mangshan National Nature Reserve and Nanling National Nature Reserve (Wu et al. 2012).

Relation to Humans
Pachytriton xanthospilos, as well as other members of the genus, has been illegally collected for the pet trade for many years. This is a contributing factor to the decreasing population (Wu et al. 2012).

Comments

PHYLOGENETIC RELATIONSHIPS:

The phylogenetic relationships of Pachytriton was determined from Bayesian Inference and Maximum Likelihood analyses using two fragments of mitochondrial DNA that include the complete coding sequence of NADH dehydrogenase subunit 2, cytochrome b, and flanking tRNAs. These results support that the clade formed by P. brevipes and P. feii is sister to P. xanthospilos (Wu et al. 2012).

ETYMOLOGY:

The species epithet, “xanthospilos” is a reference to the patterning on the dorsolateral side of the body with “xanth” meaning “orange and “spil” meaning “spot” (Wu et al. 2012).

OTHER INTERESTING INFORMATION:

Pachytriton xanthospilos was originally discovered in the European pet trade and labeled simply based on morphology as Pachytriton B. Due to a lack of field and molecular data, the specimen was not identified as a species of its own until museum specimens from 1975 and new specimens from field surveys were added to the type series to describe P. xanthospilos (Wu et al. 2012).

References

IUCN SSC Amphibian Specialist Group. (2020). "Pachytriton xanthospilos." The IUCN Red List of Threatened Species 2020: e.T89100526A122177570. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T89100526A122177570.en. Accessed on 22 February 2022.

Nishikawa, K., Jiang, J.P., Matsui, M. (2011). "Two new species of Pachytriton from Anhui and Guangki, China (Amphibia: Urodela: Salamandridae)." Current Herpetology, 30, 15-31. [link]

Wu, Y., Wang, Y., Hanken, J. (2012). “New species of Pachytriton (Caudata: Salamandridae) from the Nanling Mountain Range, southeastern China.” ZooTaxa, 3388(1), 1-16. [link]

Species Account Citation: AmphibiaWeb 2022 Pachytriton xanthospilos <https://amphibiaweb.org/species/8358> 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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