Pseudohynobius puxiongensis is a relatively small, smooth-skinned salamander with well-developed limbs. The head is depressed; the body is slightly depressed, with a cylindrical trunk. Palms and soles lack horny coverings. Four fingers are present on each hand and five toes on each foot. This species has thirteen distinct costal folds. No labial fold is present. The tail is slender, and is shorter than the snout-vent length (SVL). No obvious tail fin fold is present. Vomerine teeth occur in two obliquely arched series, which are relatively short. Coloration is uniformly grayish (Fei and Ye 2000; RaffaŽlli 2007).
Distribution and Habitat
Found on the Tibetan Plateau, in China. The type locality of P. puxiongensis is Yuexi County, Sichuan Province, on the eastern side of the Hengduan Mountains, China, at 2900 m asl (Fei and Ye 2000). This species inhabits mountain brooks (Peng et al. 2010). New localities have been reported recently, all of which are less than 3 km away from the type locality (Peng et al. 2010).
Life History, Abundance, Activity, and Special Behaviors
Larvae and egg sacs have been found at and near the type locality, along with adults. Egg sacs are spiral-shaped, containing eggs in a single string or interlaced (Peng et al. 2010).
Trends and Threats
The population status of this species is not known. The type specimen, described in 2000, was collected in 1965 from a potato cellar (an artificial cave used for potato storage), but was thought to normally be found in temperate forest. Clear-cutting of forest would thus present a threat (Fei and Ye 2004). Subsequent discoveries of more individuals have confirmed that this species lives in mountain brooks within temperate forest (Peng et al. 2010).
Possible reasons for amphibian decline
Habitat modification from deforestation, or logging related activities
This species is the only five-toed hynobiid salamander found in the Hengduan Mountains, Tibetan Plateau, where four-toed species of Batrachuperus have been known for many years (see Peng et al. 2010). Based on the presence of a unique internasal bone, Fei and Ye (2000) placed this species in a new subfamily, Protohynobiinae, thought to be the most basal within the family Hynobiidae. The presence of the internasal bone was thought to be a primitive character retained in this species but lost by a common ancestor of all other hynobiid salamanders (Fei and Ye 2000). However, this placement was based on a single specimen, collected in 1965 and described in 2000. More recently, Peng et al. (2010) have reported finding more specimens at the type locality. These authors note that the new specimens match all characters mentioned in the description of the holotype except for two. First, in contrast to the holotype, the new specimens all lack the internasal bone, suggesting that the presence of this bone in the holotype was due to individual variation (Peng et al. 2010).
Second, the holotype lacks a premaxillary fontanelle, but a very small fontanelle was present in one of the specimens examined; however, premaxillary fontanelles are known to vary in both presence/absence and size between individuals of the same species (Peng et al. 2010). These authors also sequenced the complete mitochondrial genome for this species plus two additional species of Pseudohynobius; these new sequences were used along with eighteen previously published hynobiid mitochondrial genome sequences to reconstruct a phylogeny of the family Hynobiidae and showing that Protohynobius puxiongensis is deeply nested within Hynobiidae. Peng et al. (2010) found that there was thus no support for the validity of the subfamily Protohynobiinae, and proposed changing the genus from Protohynobius to Pseudohynobius.
The karyotype is 2n=52, as is the case for the genus Pseudohynobius (Peng et al. 2010).
Fei, L. and Ye, C. (2000). ''A new hynobiid subfamily with a genus and new species of Hynobiidae from West China (Amphibia: Caudata).'' Cultum Herpetologica Sinica, 8, 64-70.
Fei, L., and Ye, C. (2004). Protohynobius puxiongensis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.2. www.iucnredlist.org. Downloaded on 23 August 2010.
Peng, R., Zhang, P., Xiong, J.-L., Gu, H.-J., Zeng, X.-M., and Zou, F.-D. (2010). ''Rediscovery of Protohynobius puxiongensis (Caudata: Hynobiidae) and its phylogenetic position based on complete mitochondrial genomes.'' Molecular Phylogenetics and Evolution, 56, 252-258.
RaffaŽlli, J. (2007). Les UrodŤles du monde. Penclen Edition, France.
Written by Kevin Gin (kevgin AT berkeley.edu), UC Berkeley
First submitted 2004-03-01
Edited by Kellie Whittaker (2010-08-23)
Citation: AmphibiaWeb: Information on
amphibian biology and conservation. [web application]. 2013. Berkeley, California:
(Accessed: May 23, 2013).
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