Paramesotriton zhijinensis, Zhao, Haitao, Che, Jing, Zhou, Weiwei, Chen, Yongxiang, Zhao, Haipeng & Zhang, Ya-Ping, 2008

Zhao, Haitao, Che, Jing, Zhou, Weiwei, Chen, Yongxiang, Zhao, Haipeng & Zhang, Ya-Ping, 2008, A new species of Paramesotriton (Caudata: Salamandridae) from Guizhou Province, China, Zootaxa 1775, pp. 51-60 : 56-59

Paramesotriton zhijinensis , new species

(Fig. 3a–d)

Holotype: BJC20070129001, an adult female collected from Shuangyan Pond (26°40’N 105°46’ E), 1310 m, Zhijin County, Guizhou Province, P. R. China; collected by Haitao Zhao in January 2007.

Paratypes: adults: BJC20060911001–3, BJC20061118001–4, BJC20070129003–4, 6, KIZ 20070919001–4; larvae: BJC20061118005–8, BJC20070129002, BJC20060911004–5, KIZ 20070919005, 22 specimens in total collected in September, November, 2006, January and September, 2007 at the same locality as the holotype.

Diagnosis: Paramesotriton zhijinensis can be distinguished from all other species of Paramesotriton by the following combination of characters: distinct yellow postocular stripe, two non-continuous, dorsolateral stripes on the dorsolateral ridges; distinct scent glands on snout (see below; Fig. 4 ), warts and glands covering much of the dorsal and ventral surfaces; orange-red spots on venter, chin, underside of axillae, cloaca and proximal portion of tail. Neoteny is common with most adult specimens having vestigal gills and gill filaments (Fig. 5a, c).

Description of the holotype: Specimen in good state of preservation. Measurements are given in Table 1 . Neotenic characteristics are absent. Holotype is relatively large and robust. The head moderately sloping in profile, relatively large and flat; skull broad with maxillaries oriented angular to body axis; head length is distinctly longer than head width. Snout short, truncate, extending beyond lower lip. Nostrils are located on the tip of snout. Gular fold is present. The eyes are relatively large, round. Upper lips thick, fleshy and overlapping lower lip from eye to snout. Maxillary and mandibular teeth are tiny and vomerine teeth form a “^” pattern. Tongue is relatively reduced and elliptical. Three turbercular dorsal ridges, one midline and two lateral, extending from behind of head to base of tail. Glands and warts cover much of dorsal and ventral surfaces.

The four fingers and five toes lack webbing. Tail is slender, laterally compressed; dorsal tail fin and indistinct ventral tail fin present; posterior end of tail rounded in lateral profile, not pointed.

FIGURE 3. (a) Lateral view of live Paramesotriton zhijinensis (BJC20060911001, paratype: Ψ). (b) Ventral view of same specimen. (c) Dorsal view of same specimen. (d) Dorsal view of live P. zhijinensis (BJC20060911003, paratype: Ψ). (e) Pool in Zhijin County, Guizhou Province, China, type locality of P. zhijinensis . (f) Algae in the pool.

Color of holotype in life: Body brown-black; three turbercular dorsal ridges with non-continuous yellow mottling. Large, irregular, orange-red spots on venter, chin, underside of axillae, cloaca and tail; some smaller and weak spots interspersed on venter. Orange-red spots diminish in size posteriorally on underside of tail base. A distinct yellow postocular stripe located near corner of mouth.

In preservative, the dorsal brown-black faded to black. Dorsal yellow spot faded to white; ventral orange faded to yellow and white.

Variation

Morphology: Measurements are given in Table 1 . Most adult paratypes have vestiges of gills, or gill filaments. All other adult morphological characteristics conform to those of the holotype.

Color variability: The dorsal stripes of adults are variable, sometimes indistinct and with tiny light yellow spots (Fig. 3d). Ventral spots vary in shape and arrangement. Coloration in larvae similar to adults except that the spots are fewer in number and larger.

Neotenic condition: Among the total of 15 adult specimens examined, two did not have gills: BJC20070129001 (holotype) and BJS20070129003. Most adult specimens exhibited vestigal gills and gill filaments (Fig. 5a, c), as is characteristic of neotenic salamanders. Adult status was verified by the presence of eggs and enlarged testes. Most specimens had three pairs of external gills, although the gill filaments were indistinct in most. In one specimen, the external gills had disappeared and a small remnant of the gill slit remained.

FIGURE 5. (a) The vestigal gill filaments of Paramesotriton zhijinensi , from specimen KIZ20070919002 (paratype: ɗ) in preservative. (b) The vestigal gill of specimen BJC20070129001 (holotype: Ψ) in preservative. (c) The vestigal gill filaments from specimen BJC20060911002 (paratype: ɗ) in preservative.

Scent glands: These small, individually distinctive and scattered pits occur on the dorsum surrounding the eyes, on both the upper and lower lips and particularly on the canthal ridge ( Fig. 4 ). They also extend along the two dorsolateral ridges. On the ventral surface, the glands form two lateral lines extending from chin to cloaca. The glands are easily observed in all living specimens but become indistinct after preservation in formalin. The glands emitted a small amount of white, malodorous secretion when touched. There was strong odor in the natural environment, however, the odor became weaker after keeping and feeding the specimens in the lab for a short period of time. The function of these glands remains to be determined.

Distribution and Habitat: Zhijin County, located on Guizhou Plateau, is surrounded by mountains. All specimens of P. zhijinensis were found within a 6700m 2 pool, which is fed by an underground spring. The clear water in the pond is warm with a temperature of about 16 °C year round. The salamanders move to the adlittoral region for feeding in the evening and are easily seen with a flashlight. In the daytime, they usually move to the bottom of the pool where they are difficult to find. In addition, the pond has large quantities of algae and fishes (Fig. 3e, f). Hence, the known habitat of P. zhijinensis is very small.

Etymology: The specific name zhijinensis is an adjective referring to its known distribution in Zhijin County, Guizhou Province, China.

Comparative Material examined: Paramesotriton caudopunctatus ( KIZ 88I 613–616 from Leigong Shan, Guizhou Province, China); Paramesotriton chinensis (alive, four specimens, personal collections from Y. Yang); Paramesotriton fuzhongensis ( KIZ 199060001–2 from Gongcheng, Guangxi Autonomous Region, China); Paramesotriton guangxiensis ( KIZ 87002, 87007 from Ningming, Guangxi Autonomous Region, China); Paramesotriton hongkongensis ( KIZ 870076–77, KIZ 7600343–112, 7600343–161 from Hong Kong, China).

Figures

FIGURE 4. The scent gland of Paramesotriton zhijinensis (red arrow).