Pachytriton inexpectatus Nishikawa, Jiang, Matsui & Mo, 2011
Yaoshan Stout Newt; Pachytriton de Guangxi
|Species Description: Nishikawa K, Jiang J-P, Matsui M, Mo Y-M 2011 Unmasking Pachytriton labiatus (Amphibia: Urodela: Salamandridae), with description of a new species of Pachytriton from Guangki, China. Zool Sci 28:453-461.|
© 2011 Kanto Nishikawa (1 of 1)
Pachytriton inexpectatus is also found at higher elevations than the species it was formerly mistaken for Paramesotriton labiatus. A larger, more robust body and wider head differentiates P. inexpectatus from the similar P. granulosus. Additionally, they are separated by a large geographic distance (Nishikawa et al. 2011). Geographic range also separates P. inexpectatus from the similar species, P. archospotus, P. brevipes, P. feii and P. xanthospilos (Wu et al. 2013).
In life, P. inexpectatus have a dark to pale brown dorsum and lateral surfaces. The background color of the ventrum is lighter than the dorsum and has reddish-orange marks that are arranged in two longitudinal lines. There are also reddish orange markings on the throat and ventral surface of the limbs. Orange markings along the ventral side appear vivid in juveniles and then dull over time into adulthood. When preserved, the colors fade with the dorsum becoming light brown and the ventrum becoming pale cream (Nishikawa et al. 2011).
Morphological variation among individuals is minimal, with the most variation seen due to age and sex. Juveniles exhibit brightly colored orange ventral spots, which diffuse in adults. An orange spot can be observed at the base of each of the limbs in juveniles. This species exhibits sexual dimorphism, with males having proportionately longer limbs and larger heads. The webbing between digits is variable in individuals (Nishikawa et al. 2011).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Most likely because of its presence in montane stream habitats, P. inexpectatus exhibits smooth skin optimal for cutaneous respiration, a broad, paddle-like tail good for propelling through the water, and a tongue for suction feeding (Nishikawa et al. 2011).
Their diet mainly consists of various species of annelids, molluscs, and insects, both aquatic and terrestrial (Nishikawa et al. 2011).
Breeding take place between April to late July in rocky moving streams. Both male and female exhibit aggressive behavior toward any animals that are coming within sight, of or near their nesting site (Nishikawa et al. 2011). However, specific breeding behavior is unknown (Nishikawa et al. 2011; IUCN 2022.)
Eggs and larvae are not commonly found, but ova found in the ovaries of females had a mean diameter range of 3.4 - 4.7 mm. Both the vegetal and animal poles of mature ova were beige while immature ova were cream colored. Clutches ranged from 32 - 89 eggs (Nishikawa et al. 2011).
Trends and Threats
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
Based on Bayesian Inference and Maximum Likelihood analyses on ~1200 base pair DNA fragments of both mitochondrial and nuclear DNA, P. inexpectatus is the sister taxon to the clade composed of P. archospotus, P. brevipes, P. feii, P. granulosus, and P. xanthospilos (Wu et al. 2013). However this analysis did not include P. moi, which a 2012 study using Bayesian Inference and Maximum Likelihood analyses on the same mtDNA fragment did. Those results largely supported the 2013 results, but found that P. inexpectatus is sister to P. moi with the next most closely related clade consisting of P. archospotus, P. brevipes, P. feii, P. granulosus, and P. xanthospilos (Wu 2012).
Pachytriton inexpectatus was previously mistaken for Parmesotriton labiatus (Nishikawa et al. 2011).
The species epithet, “inexpectatus”, is Latin for “unexpected”. It refers to the unexpected determination of P. inexpectatus as a new species despite being common in the pet trade (Nishikawa et al. 2011).
IUCN SSC Amphibian Specialist Group. (2020). "Pachytriton inexpectatus." The IUCN Red List of Threatened Species 2020: e.T88384145A122177550. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T88384145A122177550.en. Accessed on 22 February 2022.
Nishikawa K, Jiang J-P, Matsui M, Mo Y-M (2011). "Unmasking Pachytriton labiatus (Amphibia: Urodela: Salamandridae), with Description of a New Species of Pachytriton from Guangxi, China." Zoological Science, 28(6), 453-461. [link]
Sparreboom, M. (2014). "Pachytriton inexpectatus." Salamanders of the Old World. KNNV Publishing, The Netherlands, 279–81.
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]
Wu, Y., Wang, Y., Jiang, K., Hanken, J. (2013). “Significance of pre-Quaternary climate change for montane species diversity: Insights from Asian salamanders (Salamandridae: Pachytriton)”, Molecular Phylogenetics and Evolution, 66(1), 380-390. [link]
Originally submitted by: Sydni Wong, Phat Quach, Angela Gose (2022-06-06)
Description by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Distribution by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Life history by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Trends and threats by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Relation to humans by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Comments by: Sydni Wong, Phat Quach, Angela Gose (updated 2022-06-06)
Edited by: Ann T. Chang (2022-06-06)
Species Account Citation: AmphibiaWeb 2022 Pachytriton inexpectatus: Yaoshan Stout Newt; Pachytriton de Guangxi <https://amphibiaweb.org/species/7661> University of California, Berkeley, CA, USA. Accessed Sep 29, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 29 Sep 2023.
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