AMPHIBIAWEB
Pachytriton airobranchiatus
family: Salamandridae
subfamily: Pleurodelinae
 
Species Description: Li, Chen, Zhiyong Yuan, Haibin Li & Yunke Wu. 2018. The tenth member of stout newt (Amphibia: Salamandridae: Pachytriton): Description of a new species from Guangdong, southern China. Zootaxa 4399(2): 207–219.
Conservation Status (definitions)
IUCN (Red List) Status
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

 

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Description
Pachytriton airobranchiatus males have a snout-vent length range of 63.3 – 76.8 mm. Two female specimens had snout-vent lengths of 64.4 and 67.7 mm. The flat, oval head is longer than wide and appears rectangular from the dorsal view. From both the lateral and ventral view, the snout is truncate and extends beyond the jaw. The small nostrils are located close to the snout tip. From the lateral view, the loreal region has a steep slope. The small eyes have a diameter that is shorter than the snout length. The upper jaw has a distinct labial fold. A prominent gular fold is also present. The epibranchial bone is visible through the skin on either side of the neck as protrusions behind the head. The body has no costal grooves, inconspicuous dorsal vertebral groove, and smooth skin. The limbs are short and only the tips of the fore- and hind limbs touch when adpressed to the body. When extended anteriorly, the forelimb reaches the middle of the eyes. The short, slender fingers are unwebbed, have slightly developed lateral fringes, and have a relative length of I < IV < II < III. The hind limbs are longer than the forelimbs. The toes are similar to the fingers in being slender and unwebbed with slightly developed lateral fringes. The relative toe lengths are I < V < II < IV < III. The tail is rounded and broad at the base and tapers to a point at the tip. The caudal fin extends from base to tip with the caudal fin on the ventral side being more obvious in the posterior portion of the tail. The cloaca is not swollen and the slit is short (Li et al. 2018).

Pachytriton airobranchiatus is distinguished from other species in the Pachytriton genus by the bright orange blotches on the ventral side and the prominent bulges on either side of the neck behind the head caused by the epibranchial bone. However, it can be further distinguished from P. changi and P. xanthospilos by the latter two having orange, ribbon-like dots extending in dorsolateral stripes on their dorsum. The lack of costal grooves differentiates P. airobranchiatus from P. inexpectatus, P. granulosus and P. feii. Having brown coloration on the dorsal tips of the digits and slender first digits that don’t become volar pads distinguishes P. airobranchiatus from P. wuguangui. And lastly, P. airobranchiatus can be differentiated from P. moi by the former having orange blotches on its ventrum (Li et al. 2018).

In life, the coloration of the dorsal and lateral surfaces of the head, body and tail is dark brown. Black black spots may be present on the dorsum and flanks. The dorsal tips of the digits are brown. The ventral surface of the head is light brown mixed with a milky-white color. The ventrum of the body is brown with irregular bright orange blotches. Also on the ventral side, an orange line extends from vent to the end of the tail. There may be bluish-white blotches near the tip of the tail, especially in males. Preserved specimens lighten in color (Li et al. 2018).

Pachytriton airobranchiatus varies in color and pattern. Some specimens do not have black dorsal and lateral spots. The number, size, shape, and position of the orange-red blotches on the ventrum vary and may be completely absent. Lastly, the bluish-white blotches on the tail were only found on male specimens. Cloacas are larger in males than females (Li et al. 2018).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

 

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All known specimens were found on in the Lianhuashan-Baipenzhu Provincial Nature Reserve on Mt. Lianhua and the peak of Wuzhizhang, Huidong, Guangdong, China. Their habitat consists of cold, rocky mountain streams at 900 - 1,000 m in tropical broadleaf forests. The streams were composed of gravel and various sized pebbles interspersed with large boulders and still water between riffles. The full distribution of this species is currently unknown, though it is suggested that the total range is about 10 km2 (Li et al. 2018).

Life History, Abundance, Activity, and Special Behaviors
Pachytriton airobranchiatus is rarer than P. brevipes and P. granulosus and can be found as solitary individuals or in converged groups in deep pools (Li et al. 2018).

The small, cool waterways that P. airobrachiatus inhabit have a water temperature range of 15.9oC to 16.2oC at the night in April and a pH range close to 7. The species is restricted to headwaters in high mountaintops because of high temperatures in the otherwise tropical region. Because of this, the Mt. Lianhua and Wuzhizhang populations are isolated from each other (Li et al. 2018).

The forest habitat that P. airobranchiatus is found in is dominated by persimmon trees (Diospyros morrisiana), Symplocos ulotricha, tea flower trees (Camellia salicifolia and Schima superba), holly trees (Ilex ficoidea), and beeches (Lithocarpus corneus) (Li et al. 2018).

Sympatric amphibians include Amolops hongkongensis, Leptolalax liui, Odorrana graminea, Odorrana schmackeri, and Xenophrys brachykolos. Sympatric reptiles include Boulenger’s keelback snake (Hebius boulengeri), the Chinese slug snake (Pareas chinensis), the Indian Forest Skink (Sphenomorphus indicus), and the Chinese water skink (Tropidophorus sinicus) (Li et al. 2018).

Trends and Threats
In their description of the species, the species authorities of P. airobranchiatus recommended listing the species as “Endangered” because of their small range and extreme fluctuations in their environmental (IUCN criterion B1ac(ii) in Categories and Criteria version 3.1). Pachytriton airobranchiatus is restricted by physiological constraints to cool headwaters at the peaks of two mountaintops with an estimated range of approximately 10 km2. The region in which P. airobranchiatus lives experiences flooding and hurricanes during the wet season and streams may dry up during the dry season. Because of their aquatic adaptations, they cannot migrate away from drought conditions (Li et al. 2018).

Possible reasons for amphibian decline

General habitat alteration and loss
Subtle changes to necessary specialized habitat
Climate change, increased UVB or increased sensitivity to it, etc.

Comments
The species authority is: Li, C., Yuan, Z., Li, H., Wu, Y. (2018). "The tenth member of stout newt (Amphibia: Salamandridae: Pachytriton): Description of a new species from Guangdong, southern China." Zootaxa, 4399(2), 207-219.

Based on Bayesian analysis of nd2 and cytb mitochondrial DNA sequences P. airobranchiatus is sister to P. wuguanfui. However, this relationship is not strongly supported. The sister clade to the clade formed by P. airobranchiatus and P. wuguanfui is composed of P. xanthospilos and P. changi. The relationship between these two clades is strongly supported. The clade formed by these four species is sister to a clade consisting of P. feii and P. brevipes (Li et al. 2018).

Pachytriton airobranchiatus is the tenth member of the Pachytriton genus (Li et al. 2018). The species epithet, “airobranchiatus”, is derived from the Greek words, “airo” for “raised” and “branchos” for “gill”, in reference to the raised epibranchial bone of this species (Li et al. 2018).

References

Li, C., Yuan, Z., Li, H., Wu, Y. (2018). ''The tenth member of stout newt (Amphibia: Salamandridae: Pachytriton): Description of a new species from Guangdong, southern China.'' Zootaxa, 4399(2), 207-219.



Written by Elizabeth McAlpine-Bellis (mcalpine.liz AT berkeley.edu), UC Berkeley
First submitted 2018-08-22
Edited by Ann T. Chang (2018-08-22)

Species Account Citation: AmphibiaWeb 2018 Pachytriton airobranchiatus <http://amphibiaweb.org/species/8810> University of California, Berkeley, CA, USA. Accessed Dec 18, 2018.



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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Dec 2018.

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