Paramesotriton yunwuensis, Wu, Yunke, Jiang, Ke & Hanken, James, 2010

Wu, Yunke, Jiang, Ke & Hanken, James, 2010, A new species of newt of the genus Paramesotriton (Salamandridae) from southwestern Guangdong, China, with a new northern record of P. longliensis from western Hubei, Zootaxa 2494, pp. 45-58 : 51-55

Paramesotriton yunwuensis species nov.

( Fig. 3 A –G; Fig. 4 )

Holotype: CIB 97854, an adult male collected from a pool along a montane stream (22°37’N, 111°10’E; 525 m elevation) near Nanchong village, Fuhe, Luoding city, Guangdong province, P. R. China, by Yunke Wu and Ke Jiang on May 8, 2009.

Paratypes: CIB 95336–95339, 97853, 97855–97856, 97950; same collection date and locality as the holotype.

Diagnosis: Paramesotriton yunwuensis is assigned to the genus Paramesotriton by its phylogenetic position and the following characters: warts covering dorsal and lateral surfaces; bright orange blotches present on ventral surface; large body size; laterally compressed tail with rounded tip. This species can be diagnosed from congeners by a combination of adult characters: large body size; robust habitus, especially in males; head large and broad; corner of mouth located well posterior to caudal margin of eye; skin rough, warts cover dorsum of head and large warts on dorsolateral ridges; cephalic bony ridges present but not prominent; dorsal vertebral ridge flat to low, not highly protuberant; forelimb short, when extended anteriorly does not reach the caudal margin of eye; palm and tarsus of adpressed limbs do not overlap; tail long, but not deep; bright ventral blotches irregular without a network of black lines; males with bluish-white stripe on posterior half of tail in breeding season.

Description of the holotype: This is a large newt; SVL equals 100.8 mm. Habitus very robust. Head large, much wider than neck. Head longer than broad. Snout truncate, projects beyond mandible. Head slopes steeply downward anteriorly in lateral view. Skull very broad; length / width = 1.06. Labial fold well developed on lateral side of upper jaw. Vomerine tooth patch ٨-shaped; tooth rows converge anteriorly and extend slightly beyond anterior limit of choanae. Tongue elliptical, adheres to mouth floor but with free lateral margins. Frontosquamosal arch complete and robust. Posterior tip of maxillary bone articulates posteriorly with the pterygoid bone. Epibranchial bones elongated posteriorly and flared dorsolaterally. Parotoid gland prominent. Gular fold present, numerous longitudinal wrinkles on throat. Vertebral ridge flat and inconspicuous. Numerous transverse wrinkles on flanks, venter and lateral sides of tail base. Large warts present on head and dorsolateral ridges. Forelimb very short; when extended rostrally barely reaches posterior margin of eye. When forelimb and hind limb are adpressed against flank, digits tips meet but palm and tarsus do not overlap. Four fingers and five toes, no interdigital webbing. Relative length of fingers, 1 <4 <2 <3; relative length of toes, 1 <5 <2 <4 <3. Tail laterally compressed; dorsal caudal fin evident on posterior half of tail; ventral caudal fin inconspicuous. Tail tip rounded. Cloaca swollen, with transverse wrinkles; few papillae on cloacal wall.

Holotype Females (N = 5) Males (N = 3) Subadult

Measurements (CIB 97854) Range Mean ± SE Range Mean ± SE (CIB 97856) SVL 100.8 73.4–87.8 82.9 ± 2.7 93.0–104.8 99.5 ± 3.5 66.6 TTL 186.0 145.0–161.0 155.3 ± 2.8 165.1–186.0 177.2 ± 6.2 124.0 TAL 85.2 68.4–76.5 72.4 ± 1.3 72.1–85.2 77.6 ± 3.9 57.4 HL 30.7 23.1–27.6 25.2 ± 0.8 29.9–31.6 30.7 ± 0.5 20.5 HW 26.2 17.9–21.4 19.4 ± 0.6 23.3–27.1 25.6 ± 1.2 14.5 EN 8.7 6.3–7.3 6.8 ± 0.2 8.3–9.3 8.8 ± 0.3 5.6 IO 14.5 9.8–11.5 10.8 ± 0.3 12.9–15.1 14.1 ± 0.7 9.0 IN 6.9 4.9–5.9 5.4 ± 0.2 6.5–7.1 6.8 ± 0.2 4.8 AG 43.9 31.9–40.4 36.2 ± 1.5 36.4–44.2 41.5 ± 2.5 27.5 TAD 13.5 9.9–11.8 11.0 ± 0.3 13.5–15.4 14.3 ± 0.6 8.4 AL 26.5 22.0–23.8 22.9 ± 0.3 21.4–26.5 23.5 ± 1.5 20.2 PL 27.8 21.7–24.1 23.3 ± 0.4 26.2–28.8 27.6 ± 0.8 20.7

Females (N = 3) Males (N = 4)

Color of the holotype: Dorsum olive brown. Vertebral ridge darker brown with fine black margin. Venter dark orange with a few large irregular pale-orange blotches and small black flecks. Each blotch has a black margin. Chin pale-orange with dense black flecks. Anterior portion of cloaca, underside of limbs and tail orange. A single pale-orange blotch is present on the ventral surface of each limb base. A bluish-white caudal stripe on posterior half of tail.

In preservative, dorsum chocolate brown, vertebral ridge dark orange. Ventral orange coloration fades to milky white, and caudal stripe to pale white.

Variation: Morphology of paratypes resembles that of the holotype with the following exceptions. Adult females have a more conspicuous vertebral ridge, a smaller and shorter cloacal opening, and no papillae on the cloacal wall. In subadults, the skin is more densely granulated; the dorsal vertebral ridge is highly elevated; the forelimbs are relatively long and extend beyond the anterior margin of the eye when extended forward; the palm and tarsus overlap when the forelimb and hind limb are adpressed against the flank. The number of caudal vertebrae varies among specimens; the posterior tip of the maxillary bone is slightly separated from the pterygoid bone in a few specimens. Linear measurements are summarized in Table 2. Adult dorsal coloration ranges from reddish brown to olive brown; ventral color pattern varies from black background with a few orange blotches to orange background with numerous small black flecks. Arrangement of blotches and flecks is subject to individual variation. The white caudal stripe is absent in females. Subadults are black dorsally, with rounded orange blotches on a black venter.

Etymology: The specific epithet yunwuensis is derived from the name of the mountain range, Yunwu, in southwestern Guangdong.

Habitat and distribution: Paramesotriton yunwuensis is found in large pools (max. 4 × 4 m) along a montane stream at mid-elevation of the mountain near Nanchong village. Maximum water depth reaches about 3 m. Submerged boulders, small rocks and coarse gravel constitute the pool substrate. Pools are connected by currents of water that course over giant granite boulders. The water is cold, clear and slowmoving. Several species of stream fishes coexist with the newt. Broadleaf forests flourish along the site, but the stream is not covered by the canopy. Newts can be seen crawling actively on the deep pool bottom at midday and they can be found at shallower pool edges at night. Sightings of similar newts in nearby mountains are affirmed by local people. Therefore, we suggest that this species likely occurs in many montane streams in the Yunwu Mountains.

Remarks: Morphologically, Paramesotriton yunwuensis resembles but is nevertheless distinct from P. deloustali , P. guangxiensis and P. fuzhongensis . Adult P. yunwuensis have a flat or low vertebral ridge and lightly granular warts and the other three species have a high vertebral ridge and densely granulated warts ( Bourret 1934; Huang et al. 1983; Wen 1989). The new species also has short limbs. For example, when the forelimb is stretched forward in P. yunwuensis it does not reach the posterior margin of the eye. In P. deloustali the extended forelimb reaches the midpoint of the eye and in P. fuzhongensis it reaches even further anteriorly to a point midway between the eye and the nostril ( Wen 1989). When the forelimb and hind limb are adpressed against the flank in P. yunwuensis only the digit tips overlap. In contrast, the palm and tarsus overlap in P. fuzhongensis ( Wen 1989) . The new species is readily differentiated from P. guangxiensis by its larger body size (SVL females 73.4–87.8 mm, males 93.0– 104.8 mm), robust habitus, and long and relatively shallow tail. Paramesotriton guangxiensis is smaller (SVL female 71.0 mm, males 67.8–75.5 mm), more gracile (e.g., the trunk is relatively flat in cross-section, versus square or round in P. yunwuensis ), and its tail is short and deep ( Huang et al. 1983).

The type locality of P. yunwuensis lies within a small scenic park. Local villagers use baited fishing line (e.g., earthworms) as well as electrofishing equipment to catch newts and sell them to tourists as juvenile Andrias davidianus (Chinese giant salamander). It is unlikely that these human activities associated with tourism are sustainable. According to the IUCN Red List Categories and Criteria version 3.1 (http:// www.iucnredlist.org), we consider this species as near threatened. Appropriate conservation measures should be implemented to prevent extirpation of P. yunwuensis from its type locality and other naturally occurring populations.

Figures

FIGURE 4. Left: montane pools at the type locality of P. yunwuensis near Nanchong village. Right: the stream that connects a cascade of pools at the same site.

FIGURE 3. A & B: dorsal and ventral views of male Paramesotriton yunwuensis sp. nov. (CIB 97854, holotype). C & D: ventral and dorsal views of female P. yunwuensis (CIB 97950, paratype). E & F: ventral and dorsal views of a subadult (CIB 97856, paratype). G: the holotype in preservative.