Zhao Ermi's Smooth Warty Newt, Spotless Smooth Warty Newt; Paramesotriton de Zhao Ermi, Paddletail newt
|Taxonomic Notes: The genera Pachytriton and Paramesotriton have had a confused taxonomic history, complicated by the fact that a number of these salamanders have long been in the pet trade, identified as Paddletailed and Warty Newts, respectively. In 1985 Frost (Amphibian Species of the World) recognized only one Pachytriton, P. brevipes, and 5 Paramesotriton. At present 8 species of Pachytriton and 13 species of Paramesotriton are recognized. The pet trade long identified the following biological entities: Phenotypes Pachytriton A, B, C and D, none of them assignable to P. brevipes. Eventually Pachytriton labiatus was associated with phenotype A, but the other phenotypes were of uncertain taxonomy. In 2011 Nishikawa et al. discovered that the nomen labiatus belongs to a biological entity that had been recently named Paramesotriton ermizhaoi, and Phenotype A was assigned to Pachytriton granulosus (which had been in the synonymy of other taxa). Raffaelli (Les Urodeles de Monde, 2nd Ed 2013) thinks that Phenotypes A are taxonomically heterogenous, and include in addition to Pachytriton granulosus, Pachytriton feii, Pachytriton moi and Pachytriton inexpectatus; Phenotype B is thought to be Pachytriton changi (and we think also Pachytriton xanthospilos); Phenotype C is thought to be Paramesotriton labiatus; Phenotype D is thought to be Paramesotriton archospotus. No members of the genus Paramesotriton (Warty Newts) should be called Paddletailed newts; that name should refer only to Pachytriton (which are also known as Stout Newts). For formal taxonomic history see Amphibian Species of the World website.|
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 Guangxi, China. Zoological Science, 28(6):453-461.
© 2008 Boris I. Timofeev (1 of 15)
Live animals are uniformly brown to dark brown on the dorsal side, and lack the black dots that characterize P. brevipes. Some P. labiatus develop two dorsolateral lines of red flecks. Orange blotches are present on the ventral side, which are well defined in juveniles, blurred in subadults, and finally washed out in aged animals. After preservation, the orange or red coloration turns to ivory white. No pattern difference is confirmed between males and females.
Larvae are gray on the back and white on the ventral side (Zhao et al. 1994). Fully metamorphosed juveniles reach about 70 to 80 mm, and are sexually mature at 125 mm (Fei et al. 2006).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
The breeding season typically begins in April and lasts to July (Fei et al. 2006), but populations in Guangdong Province (southernmost distribution) may postpone to September and October (Xu et al. 2002). Under captivity, the species exhibit certain courtship behaviors (Sparreboom and Thiesmeier 1999). When a male senses the presence of a female, he swims toward her immediately and tries to block her path. Then the male positions itself perpendicular to the female's body, slowly fanning his tail tip near her snout. The female may either swim away or stay motionless if she is interested. After several bouts of tail-fanning, she moves towards the male, who turns around and begins to retreat. The female touches the male's tail while following. Finally, the male deposits a spermatophore and the female, creeping behind, picks it up with her cloaca.
Females lay around 40 single eggs at the lower surface of the rocks in the streams, and sometimes the eggs congregate to form a patch (Zhao et al. 1994). However, more than 160 eggs can be found in the ovaries of gravid females (Xu et al. 2002). The ovum is milky white and attains 3 to 4 mm in diameter (Zhao et al. 1994). There are three jelly capsules enclosing the ovum, so the egg is about 10 mm in diameter (Zhao et al. 1994). The incubation period is around 2 months at the water temperature of 13~15 degrees C, and females vigorously protect the egg clutch (Thiesmeier and Hornberg 2003). Females do not leave the nesting site during this period and may eat dead eggs (Sparreboom and Thiesmeier 1999).
Paramesotriton labiatus feeds on earthworms, other aquatic arthropods and insect larvae. The author observed two animals scrambling for the same earthworm from the two ends. After their snouts met, they rolled rapidly like feeding crocodiles. When captured, the animal may emanate a strong sulfurate odor (Fei et al. 2006). It may also emit food from the stomach. Zhao et al. (1994) recorded anti-predator postures including stretching limbs, lifting the head and tail, and exposing the orange ventral blotches.
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
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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.
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Zhao, E. and Hu, Q. (1988). ''Studies on Chinese tailed amphibians.'' Studies on Chinese Salamanders. E. Zhao, Q. Hu, Y. Jiang and Y. Yang, eds., Society for the Study of Amphibians and Reptiles, 1-44.
Zhao, X.B., Zeng, L., Zeng J.D., and Lei, Y.S. (1994). ''The ecological study of Pachytriton labiatus in Yunshan National Park (in Chinese).'' Journal of Shaoyao College, 7, 147-149.
Written by Yunke Wu (yunkewu AT fas.harvard.edu), MCZ, Harvard University
First submitted 2008-05-30
Edited by Kellie Whittaker (2015-12-14)
Species Account Citation: AmphibiaWeb 2015 Paramesotriton labiatus: Zhao Ermi's Smooth Warty Newt <http://amphibiaweb.org/species/4268> University of California, Berkeley, CA, USA. Accessed Jan 20, 2019.
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Citation: AmphibiaWeb. 2019. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 20 Jan 2019.
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