Tylototriton umphangensis, Pomchote & Peerachidacho & Hernandez & Sapewisut & Khonsue & Thammachoti & Nishikawa, 2021

Pomchote, Porrawee, Peerachidacho, Parada, Hernandez, Axel, Sapewisut, Pitak, Khonsue, Wichase, Thammachoti, Panupong & Nishikawa, Kanto, 2021, A new species of the genus Tylototriton (Urodela, Salamandridae) from western Thailand, ZooKeys 1072, pp. 83-105 : 83

Tylototriton umphangensis sp. nov.

Thai name: Ka Tang Nam Umphang English name: Umphang crocodile newt Figures 3 , 4 , 5

T. uyenoi : (referring to the population from Umphang, Tak Province): Hernandez et al. 2019, page 18.

Holotype.

CUMZ-A-8243, adult male, collected from Umphang Wildlife Sanctuary, Tak Province, western Thailand, approximate coordinate 16°12'N, 98°58'E; ca 1,150 m a.m.s.l., collected on 19 June 2021 by Porrawee Pomchote and Pitak Sapewisut.

Paratypes.

CUMZ-A-8244, CUMZ-A-8245, and CUMZ-A-8246; three adult males, same data as the holotype.

Etymology.

The specific epithet Tylototriton umphangensis refers to Umphang Wildlife Sanctuary, the type locality of the new species.

Diagnosis.

The new species is placed in the genus Tylototriton by having a combination of dorsal granules present, dorsolateral bony ridges on head present, knob-like warts (rib nodules) on dorsolateral body present, and quadrate spine absent. Tylototriton umphangensis sp. nov. differs from its congeners by having the following morphological characters: medium-sized, adult SVL 65.6-75.3 mm in males; skin rough with fine granules; snout truncate; quadrate regions laterally protruding; antero-medial ends of dentaries distinctly expanded; dorsolateral bony ridges on head prominent, steep, rough, narrow, and posterior ends curved medially; parotoids distinct, oriented rather parallel to the body axis and posterior part curved upwards in the lateral view; vertebral ridge distinct and segmented; rib nodules 14-15, small, and indistinct; limbs long and thin; tips of forelimbs and hindlimbs overlapping when adpressed along the body; tail thin.

Description of holotype.

Body rather slim and long (RTRL 76.6%); skin rough; fine granules dense on dorsum, dense on sides of body and tail, and arranged in transverse striations on mid-ventrum; head longer than wide (HW/HL 0.97), hexagonal in shape, depressed, and slightly oblique in profile; snout truncate, hardly projecting beyond lower jaw; nostrils close to snout tip, not visible from dorsal view; quadrate regions protruding laterally from dorsal view; antero-medial ends of dentaries distinctly expanded; dorsolateral bony ridges on head narrow, rough, and posterior ends curved proximally; sagittal ridge on head short and weak; labial fold absent; tongue oval, attached to anterior floor of mouth, free laterally and posteriorly; vomerine tooth series in an inverted V-shape, converging anteriorly and reaching choanae; parotoids distinct, projecting posteriorly, posterior ends slightly curved medially, oriented rather parallel to body axis and curved upwards in lateral view; gular fold present; costal folds absent; vertebral ridge prominent, narrow, and slightly segmented from neck to groin, separated from sagittal ridge on head; two low and flat bony ridges on the dorsal head surface forming a “V” shape, connected with the anterior end of vertebral ridge; rib nodules small, indistinct, forming knob-like warts, 15 on each side of body from axilla to base of tail; rib nodules slightly increasing in size from most anterior to forth nodule, then decreasing posteriorly; forelimbs (34.2% SVL) shorter than hindlimbs (40.0% SVL); tips of forelimb and hindlimb overlapping when adpressed along body; fingers and toes well developed, free of webbing; fingers four, comparative finger lengths 2> 3> 1> 4; toes five, comparative toe lengths 4> 3> 2> 5> 1; tail laterally compressed, dorsal fin more distinct posteriorly, ventral edge smooth, tip pointed; tail short (91.9% SVL); cloaca slightly swollen; vent slit longitudinal.

Color of holotype.

In life, dorsal ground coloration is dark-brown to blackish-brown, while the ventral color is slightly lighter than dorsum. Dorsal, ventral, and lateral of head, parotoids, vertebral ridge, rib nodules, limbs, vent region, and whole tail are orange-brown. Tip of tail is slightly lighter than dorsal and lateral sides of tail. Ventral side of head, part of pectoral and pubic region, limbs, and tail prominently lighter than dorsum. The lightest is the ventral edge of the tail. The lighter region between the ventral edge of the tail and the area of the vent is connected. Color of digit tips is dark brown. After a week in preservation, the color pattern is rather similar to that in life.

Measurement of holotype (in mm).

SVL 72.7; HL 16.4; HW 15.9; MXHW 18.1; SL 6.3; LJL 16.7; ENL 4.2; IND 4.3; IOD 9.6; UEW 1.6; UEL 4.7; OL 2.1; AGD 39.3; TRL 55.7; TAL 66.8; VL 6.3; BTAW 10.6; MTAW 1.7; BTAH 11.2; MXTAH 8.8; MTAH 8.7; FLL 24.9; HLL 29.1; 2FL 5.3; 3FL 4.1; 3TL 6.5; and 5TL 3.5.

Variation.

Some differences in morphology were observed among the four specimens. The dorsolateral bony ridges on the head of one paratype (CUMZ-A-8245) are rougher than the holotype and the other paratypes. The sagittal ridge on the head of one paratype (CUMZ-A-8244) is smaller and weaker than the holotype and the other paratypes. Two paratypes (CUMZ-A-8245 and CUMZ-A-8246) have a more distinctly segmented vertebral ridge than the holotype and the other paratype. The holotype has much more distinct rib nodules than the three paratypes. Sizes of rib nodules varied from rounded anteriorly to irregularly shaped posteriorly among the paratypes. One paratype (CUMZ-A-8246) has an undulated surface of the dorsal fin, while the other type specimens have an even-surfaced dorsal fin. Type specimens are generally similar in color pattern, but the coloration of the dorsal, ventral, and lateral head, parotoids, vertebral ridge, rib nodules, limbs, and whole tail is much lighter in the holotype than the three paratypes. The color of the digit tips of the holotype is dark brown, but those of the paratypes are black. Morphological variations between the specimens are shown in Figure 5 .

Comparisons.

Tylototriton umphangensis sp. nov. differs from the other species of subgenus Tylototriton Tylototriton as follows: from T. taliangensis by having orange-brown markings on the head, trunk, limbs, and tail (vs uniformly black body except for distal fingers, toes, and posterior parotoids in T. taliangensis ); from T. kweichowensis and T. pseudoverrucosus by having separated rib nodules (vs connected orange markings forming continuous dorsolateral lines in T. kweichowensis and T. pseudoverrucosus ); from T. shanorum and T. anguliceps by having a sagittal ridge and rather steep dorsolateral bony ridges on the head (vs no sagittal ridge and rather flat dorsolateral bony ridges on head in T. shanorum , and prominent sagittal ridge and the posterior ends of dorsolateral bony ridges distinctly curved medially in T. anguliceps ); from T. ngarsuensis by having truncate snout in dorsal view (vs rounded in T. ngarsuensis ); from T. himalayanus by lacking grooves on either side at the basal tail (vs present in T. himalayanus ); from T. yangi by having uniformly orange-brown parotoids (vs black coloration except for posterior end of parotoids with orange coloration in T. yangi ); from T. kachinorum , T. pulcherrimus , and T. shanjing by having light orange-brown on part of pubic region (vs light yellowish-grey ventral surfaces in T. kachinorum , and yellowish-orange to bright yellow ventral trunk in T. pulcherrimus and T. shanjing ); from T. verrucosus by having rough dorsolateral bony ridges (vs smooth in T. verrucosus ); from T. podichthys and T. phukhaensis by having short and weak sagittal ridge on the head (vs indistinct sagittal ridge on head in T. podichthys , and narrow, long, and prominent sagittal ridge on head in T. phukhaensis ); from T. panwaensis by having narrow vertebral ridge (vs wide in T. panwaensis ).

Distribution.

Umphang Wildlife Sanctuary, Tak Province, western Thailand (Fig. 1 ). The Umphang Wildlife Sanctuary is located along the Dawna Range, which is a mountain range in eastern Myanmar and northwestern Thailand. Thus, this species is expected to also occur in Myanmar and elsewhere in western Thailand.

Natural history.

All specimens were found during the afternoon at around 14:30 h hidden under leaf litter and between stems of arrowroot plants (family Marantaceae ) in a small ephemeral pond (Fig. 7 ) during the rainy season, which is the breeding season of Tylototriton species. The pond had clear water and the bottom was covered with dense leaf litter. The surrounding area was composed of hill evergreen forest. The pond size was approximately 520 cm long, 270 cm wide, and 17 cm in maximum depth. The water temperature was 23.1 °C. The water quality parameters were: pH 6.4; dissolved oxygen 4.13 mg/L; conductivity 23 µS /cm; total dissolved solid 15 mg/L; and turbidity 7.6 NTU. No fish were observed.

Figures

Figure 1. Localities for the Tylototriton umphangensis sp. nov., (circle = type locality) at Umphang Wildlife Sanctuary, Tak Province and the distribution of its closely related species. T. uyenoi (number) in Thailand: 1 Namtok Mae Surin NP, Mae Hong Son Province 2 Doi Mak Lang 3 Doi Ang Khang 4 Chiang Dao WS 5 Doi Suthep-Pui 6 Doi Chang Kien 7 Doi Inthanon 8 Doi Mon Jong, Chiang Mai Province 9 Doi Soi Malai, Tak Province and 10 Khao Laem NP, Kanchanaburi Province. NP = National Park and WS = Wildlife Sanctuary. The map is modified by N. Taewcharoen.

Figure 3. Male Tylototriton umphangensis sp. nov.

Figure 4. The male holotype of Tylototriton umphangensis sp. nov. and other specimens of T. uyenoi in preservative. A Holotype specimen of Tylototriton umphangensis sp. nov. (CUMZ-A- 8243) B Topotypic specimen of T. uyenoi (THNHM 10319) from Doi Suthep-Doi Pui NP, Chiang Mai Province C specimen of T. uyenoi (THNHM 13866) from Doi Inthanon NP, Chiang Mai Province A 1 - C 1 dorsal view of the body. A 2 - C 2 ventral view of the body. A 3 - C 3 dorsal view of the head A 4 - C 4 lateral view of the head. Scale bars: 20 mm (A 1 - C 1, A 2 - C 2); 10 mm (A 3 - C 3, A 4 - C 4).

Figure 5. Holotype (CUMZ-A- 8243) and paratypes (CUMZ-A- 8244, CUMZ-A- 8245, and CUMZ-A- 8246) of Tylototriton umphangensis sp. nov. before preservation. A dorsal view B ventral view. Scale bar: 20 mm.

Figure 7. Habitat at the type locality of Tylototriton umphangensis sp. nov. at Umphang Wildlife Sanctuary, Tak Province, western Thailand.