Tylototriton notialis, Stuart, Bryan L., Phimmachak, Somphouthone, Sivongxay, Niane & Robichaud, William G., 2010

Stuart, Bryan L., Phimmachak, Somphouthone, Sivongxay, Niane & Robichaud, William G., 2010, A new species in the Tylototriton asperrimus group (Caudata: Salamandridae) from central Laos, Zootaxa 2650, pp. 19-32 : 23-27

Tylototriton notialis sp. nov.

Holotype: FMNH 271121 (field tag BLS 10775), adult male ( Fig. 3 ), Laos, Khammouan Province, Boualapha District, Nakai-Nam Theun National Protected Area, Nam On River catchment, Phou Ak escarpment, 17°38'39.6"N 105°44'12.3"E ( Fig. 4 ), 980 m elev., coll. 27 May 2007 by Bryan L. Stuart, Somphouthone Phimmachak, and Niane Sivongxay.

Paratypes: FMNH 271120, adult male ( Fig. 3 ), same data as holotype except coll. 26 May 2007. FMNH 271122, adult female, same data as holotype except 17°39'03.4"N 105°44'25.2"E, ca. 1,000 m elev., coll. 22 May 2006 by William G. Robichaud.

Referred material: FMNH 271125 (one larva; Fig. 5 ), same data as paratype male. FMNH 271129 (nine larvae), same data as paratype male except coll. 29 May 2007.

Subgenus: The new species is assigned to the subgenus Yaotriton Dubois & Raffaëlli 2009 (= T. asperrimus species group of Fei et al. 2005) based on its phylogenetic position ( Fig. 1 ) and mostly dark dorsal and ventral coloration ( Dubois & Raffaëlli 2009).

Etymology: The specific epithet taken from notialis L. for southern, in reference to the new species having the southernmost known locality of any member in the T. asperrimus group.

Diagnosis: Tylototriton notialis is a Tylototriton (Yaotriton) having the combination of distinct, knob-like rib nodules (dorsolateral row of glandular warts); glandular warts on most of the remaining dorsal and ventral surfaces; very dark brown to black coloration on dorsum and venter; and bright orange coloration on rib nodules and posterior end of parotoid.

Description of holotype: Habitus moderately stout. Head broader than body, longer than wide, slightly sloping in profile. Snout short, truncate in dorsal view, rounded in profile, exceeding beyond lower jaw. Nostrils close to snout tip, right nostril slightly visible from above. Vomeropalatine teeth in two rows, anteriorly in contact and beginning posterior to the anterior margin of the choanae, converging into two parallel rows briefly, then diverging from one another. Glandular ridge on midline of crown from above anterior edge of eye to middle of head. Glandular ridge on outer margin of crown from above eye to base of parotoid. Parotoids enlarged, projecting backward. Glandular patch of skin on nape. Distinct vertebral tubercular ridge from posterior end of crown to base of tail, separated from ridge on midline of crown. Dorsolateral row of approximately 14 large glandular warts (rib nodules) on each side from level of axilla to base of tail, distinctly knob-like anteriorly, becoming smaller posteriorly, merging at level of groin. Smaller, glandular warts on most of remaining dorsal and ventral surfaces, warts on crown, nape, and back with clusters of glands and sometimes conical, those on throat granular and widely spaced, those on belly arranged in striations perpendicular to body axis, with a smooth, glandular, ovoid patch of skin on chest. Weak gular fold present. Four fingers, five toes, all without webbing. Tail laterally compressed, narrow dorsal fin, smooth ventral ridge, tip acuminate in profile.

Color of holotype in life: Body very dark brown. Margin of upper and lower lip, posterior end of parotoid, dorsolateral glands (rib nodules), dorsal margin of tail, outer margin of upper surface of hand and finger tips, lower surface of hand except center of palm, dorsal surface of toe tips, ventral surface of toes and extending from fifth toe to base of foot, cloacal region continuing to ventral ridge of tail bright orange.

Anterior surface of forelimb from axilla to base of first finger with narrow, broken, yellow stripe. Anterior and ventral surfaces of hindlimbs with small, scattered yellow spots. Iris dark brown, pupil black.

Color of holotype in preservative: Body faded to a lighter shade of brown. Orange markings faded to yellow or creamy-yellow.

Measurements of holotype: SVLA 60.2; SVLP 69.1; AXGR 30.5; TTL 130.4; TAL 63.1; TAD 6.5; HL 19.6; HW 15.9; EN 4.0; IN 4.9; AL 23.7; PL 23.0.

Variation: The body coloration of the paratype male (collected on land) was black rather than very dark brown as in the holotype (collected in water) and paratype female (collected on land). Böhme et al. (2005) reported that T. vietnamensis taken on land were darker in coloration than those living in water. Measurements are summarized in Table 3 .

Larvae: Two size classes of larvae were obtained in syntopy with the holotype: FMNH 271125 (one larva) with TTL 33.1, and FMNH 271129 (nine larvae) with TTL 17.8–20.9 (mean 19.4 ± S.D. 0.9).

Distribution and natural history: The new species is currently known only from the type locality, although it likely also occurs in adjacent Vietnam given its proximity to the border. All were taken in evergreen mixed with deciduous and pine forest ( Fig. 6 ). The holotype and larvae were collected at 1940– 2042 h on the stream bottom under 10–30 cm of water ( pH 5.0, temperature 19.5ºC) in a 3 m wide stream with slow current and sand and bedrock substrate, including leaf litter-filled potholes, just upstream from a 3 m high chute over bedrock. The paratype male was found at 1030 h, 30 cm above the ground on a 20 cm diameter log covered by another log, approximately 20 m from a steep escarpment. The type locality lies near the former Ho Chi Minh Trail, and a large, unexploded bomb dropped by American forces during the war was embedded in the ground approximately 3 m from the paratype male ( Fig. 7 ). The paratype female was found during the day on the damp forest floor.

The testes of the holotype and paratype males are mature but not enlarged, suggesting these males were in their first reproductive season. The paratype female has enlarged oviducts, indicating that she had recently laid eggs. Eggs of the new species were not found.

Conservation: Overharvesting for traditional medicine and the international pet trade has been identified as a major threat to Asian salamandrids ( Rowley et al. 2010). The formal description of Laotriton laoensis ( Stuart & Papenfuss 2002) , the first salamandrid known from Laos, inadvertently led to its exploitation for the international pet trade ( Stuart et al. 2006). That species is now protected from commercial collecting by national legislation in Laos. It is hoped that the muted coloration and superficial similarity of T. notialis to other members of the T. asperrimus group will minimize its demand in the international pet trade. The new species’ occurrence in a remote area within Nakai-Nam Theun National Protected Area, which is one of Laos’ largest and best-funded national protected areas ( WMPA 2005), should also afford it protection.

Comparisons: Tylototriton notialis differs from all other species in the T. asperrimus group by having bright orange coloration on the posterior end of the parotoids (parotoid coloration dark like dorsum in all other species). Tylototriton notialis differs from T. asperrimus , T. wenxianensis , T. hainanensis , and T. cf. vietnamensis from Cao Bang Province, Vietnam, by having bright orange coloration on the rib nodules (uniformly dark dorsum in T. asperrimus , T. wenxianensis , T. hainanensis , and T. cf. vietnamensis ). Tylototriton notialis differs from T. vietnamensis by having glandular warts on most of the dorsal and ventral surfaces and very dark brown to black body coloration ( T. vietnamensis with mostly smooth skin and gray to tan body coloration). Tylototriton notialis further differs from T. hainanensis , T. vietnamensis , and T. wenxianensis by having knob-like rib nodules (slightly flattened rib nodules in T. vietnamensis and T. hainanensis and indistinct nodules in T. wenxianensis ).

Figures

FIGURE 1. Fifty percent majority-rule consensus phylogram resulting from mixed-model Bayesian analysis of mitochondrial DNA from salamandrids. Numbers at nodes are Bayesian posterior probabilities. Numbers in parentheses refer to ID in Table 1.

FIGURE 3. Tylototriton notialis sp. nov. in life. From top to bottom: dorsal view of holotype (FMNH 271121), dorsal view of paratype (FMNH 271120), ventral view of holotype (FMNH 271121), ventral view of paratype (FMNH 271120).

FIGURE 4. Map illustrating the type localities of Tylototriton notialis sp. nov. (star) and T. vietnamensis (circle).

FIGURE 5. Dorsal and lateral view of larva (FMNH 271129) of Tylototriton notialis in preservative (total length 20.9 mm).

FIGURE 6. Habitat of Tylototriton notialis at the type locality.

FIGURE 7. Microhabitat (log in foreground) of the paratype (FMNH 271120) of Tylototriton notialis. The arrow indicates an unexploded bomb dropped by American forces during the war.

Tables

TABLE 3. Measurements (mm) of Tylototriton notialis sp. nov., T. vietnamensis, and T. cf. vietnamensis. Abbreviations defined in the text.

Measurement T. notialis sp. nov. Khammouan, Laos Males (n =2) Female (n =1) Range SVLA 56.5–60.2 73.4	T. vietnamensis types a Bac Giang, Vietnam Males (n =3) Range; Mean ± SD 48.3–53.6; 50.7 ± 2.7	T. vietnamensis topotypes Bac Giang, Vietnam Males (n =2) Range 61.3–62.8	T. cf. vietnamensis Cao Bang, Vietnam Males (n =30) Range; Mean ± SD 56.1–68.4; 61.7 ± 3.2
SVLP 64.5–69.1 78.0	-	66.0–69.8	61.5–74.3; 67.7 ± 3.5
AXGR 27.1–30.5 39.3	-	30.6–33.7	28.4–39.4; 34.0 ± 2.4
TTL 109.1–130.4b 141.8	113.9–121.8; 118.4 ± 4.1	125.3–125.4	109.6–142.3; 126.1 ± 7.5
TAL 45.3–63.1 2 65.2	62.4–63.9; 63.1 ± 0.8	55.6–59.4	44.7–68.5; 58.4 ± 5.4
TAD 6.5–7.1 7.4	6.6–8.0; 7.4 ± 0.7	8.0–8.1	6.4–9.2; 7.6 ± 0.7
HL 19.4–19.6 21.5	15.3–18.6; 17.2 ± 1.7	18.3–18.4	17.5–21.2; 19.3 ± 0.9
HW 15.8–15.9 19.4	15.7–17.0; 16.5 ± 0.7	16.8	15.7–18.9; 17.2 ± 0.9
EN 3.5–4.0 4.7	4.0–4.4; 4.1 ± 0.2	3.8–4.4	3.2–4.3; 3.7 ± 0.3
IN 4.9–5.0 5.8	5.4–6.1; 5.7 ± 0.4	5.6–5.7	4.3–6.2; 5.4 ± 0.4
AL 22.9–23.7 26.6	16.0–19.8; 18.2 ± 2.0	20.9–22.4	18.5–25.9; 22.2 ± 1.6
PL 22.7–23.0 28.0	20.1–21.3; 20.7 ± 0.6	22.2–23.5	18.6–24.1; 21.5 ± 1.6
Data from Böhme et al. (2005) Tail tip missing in paratype male