Tsitou Newt

A moderate to large newt. Fully grown adults can attain more than 170 mm in total length (90 mm in snout-vent length). The total length of most individuals is between 130 and 170 mm. Tail is shorter than the snout-vent length. Head is wide and flat, and trunk is stout and fat. Skin is very smooth with mucus. Small nostrils situated at tip of the somewhat flat snout. Eyes are small, and located at or anterior to the jaw angle. Well developed labial folds are present on upper jaw. Two lines of vomerine teeth orient in a ¦«-shaped manner, converging anteriorly. Transverse gular fold is often obvious on the ventral side. Parotoid region is evident, but the parotoid gland itself is absent (Sauvage 1876). Some specimen exhibits a vertebral groove. Both limbs are short and weak with respect to the robust body. When forelimb and hind limb are pressed towards each other against the flank, digits never meet (Fei et al. 2006). The fingers and toes are short, and their tips are flat and rounded. Webs are present at the base of digits in some animals, whereas others are nearly half-webbed. The lengths of fingers are 3 > 2 > 4 > 1, and the lengths of toes are 3 > 4 > 2 > 5 > 1. Tail is rounded at the anterior half, and become laterally compressed for the posterior half. Sexually mature males possess papillae at the cloaca. Juveniles have relatively longer limbs, but otherwise are similar to adults.Animals are dark brown to light yellow on the dorsal side in life. Ventral color is lighter to even bright orange. Numerous black dots are scattered around the body and tail, and intensify on the dorsum (Fei et al. 2006). When preserved in alcohol, the background color becomes palish brown on top and ivory brown below (Chang 1936). The size and density of black dots varies intraspecifically. Some newts lack black dots on the ventral side, and some are entirely spotless (Fei et al. 2006). During the breeding season, males develop a few white spots near the tip of the tail.Pachytriton is a common newt in the commercial pet trade. Novel color patterns are frequently being recognized, providing the basis of classifying new phenotypes. Thiesmeier and Hornberg (1997) described two potential new species (Pachytriton A and B in their paper) and discussed their difference to the two named species, mainly in the context of coloration. The males of Pachytriton A exhibited ornamental white and blue spots throughout the tail during mating season, making this phenotype most sexually dimorphic. Otherwise the adults are chromatically similar to P. brevipes. However, juveniles of Pachytriton A are spotless (similar to the coloration of P. labiatus) but develop black dots when older. Thus Thiesmeier and Hornberg (2003) considered Pachytriton A as closer to P. labiatus. Correspondingly, Pachytriton B lacks the distinctive dark spots as in P. brevipes, but has small dorsolateral red flecks stretching like ribbon which can be observed in P. labiatus. Yet the animal is brighter and much flatter and stouter than characteristic P. labiatus. Scholz (1998) reported the discovery of Pachytriton C, which is cloudy brown with vague black flecks dorsally and dirty orange underneath. In contrast to the normal smooth skin found in Pachytriton, the skin of Pachytriton C is relatively rough. Lastly, Raffaelli and Wallays (pers. comm.) have distinguished a fourth new phenotype called Pachytriton D, which is the largest among all. The extremely wide head and muscular long limbs are diagnostic to congeners. Small diffused dark spots are visible on dark brown to chocolate brown dorsum, and lichen-like yellow markers are present on the ventral side.

Pachytriton brevipes is distributed in Southeastern China (Zhejiang, Jiangxi, Hunan, Fujian, Guangdong, Guangxi Provinces) and Northern Vietnam (Fei et al. 2006). It is associated with montane broadleaf and mixed forests at 800 to 1700 m above sea level (Fei et al. 2006).

The species lives in various montane streams, which can be a mere one meter wide and 20 cm deep. Large number of animals can also be found in slow-running ponds with depth more than a meter. They are most abundant in rock-bound streams at higher elevation. During daytime, the newts rest at the bottom or hide in the crevices (Fei et al. 2006), and may feed on small prey such as frog tadpoles (Pope 1931), they are more active and abundant at night. Pachytriton brevipes is never observed to leave the stream, thus it is probably permanently aquatic (Pope 1931; Özeti and Wake, 1969). When captured or harassed, the animal emanates a strong sulfurate odor (Pope 1931; Fei et al. 2006). From the author¡¯s field experiences, the secreted mucous is at least lethal to other amphibians. Breeding season is from May and lasts until August. Males have a swollen cloaca with protruded papillae, and a few whitish spots develop near the tip of the tail. Fertilization is internal through the delivery of spermatophores. Females lay 30 to 60 single eggs attached to the lower surface of rocks in the stream (Fei et al. 2006). Eggs are milky white and form a compact clutch. The ovum is around 4.5 mm in diameter and the egg attains 7.5 mm if jelly capsules are included (Fei et al. 2006). Since Pachytriton labiatus females vigorously guard the eggs, P. brevipes could have maternal care as well. Eggs hatch as free-living larvae. Both females and males are territorial and show aggression to intruders. The animal feeds on aquatic arthropods and tadpoles of other amphibians. Insects that fall into the water are likely to be found in the stomach as well.

This newt is abundant in its range, yet no detailed work has recorded the population dynamics. Local inhabitants may collect them for consumption (Fei et al. 2006). Pachytriton brevipes is poisoned when people poison the entire stream to catch fish. Although this species is indirectly protected if it occurs in national parks, there is no regulation of wild exploitation (IUCN 2006).