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A NEW SPECIES OF SALAMANDER, - genus Tylototriton (Urodela: Salamandridae), from Northern Vietnam

Wolfgang Böhme, Thomas Schöttler, Nguyen Quang Truong & Jörn Köhler

Abstract. We describe a new species of Tylototriton from lowland forest of Bac Giang Province in northern Vietnam. The new species is mainly characterized by skin covered with relatively small warts and glands, flattened head, dorsal colour uniformly greyish tan or light brownish in life without larger orange or red dorsal markings. The species presumably reproduces in forest ponds during the rainy season. Records of Tylototriton asperrimus from northern Vietnam are briefly discussed. Key words. Amphibia: Urodela: Salamandridae: Tylototriton; new species; Vietnam.
Introduction
Within the last decades the herpetofauna of Vietnam has received considerable attention from native and foreign researchers. As a result, the number of known species has increased remarkably. New records and species discoveries are the almost inevitable result of every scientific expedition to remote forest areas (e.g. INGER et al. 1999, ZIEGLER et al. 2000, 2004). Concerning salamanders, four species have so far been reported for the country: Paramesotriton deloustali (BOURRET, 1934), Paramesotriton guanxiensis (HUANG, TANG & TANG, 1983), Tylototriton verrucosus ANDERSON, 1871 and Tylototriton asperrimus UNTERSTEIN, 1930 (NGUYEN & HO 1996, ORLOV et al. 2002, SELGIE et al. 2003, NGUYEN et al. 2005). However, there are frequent anecdotal reports of supposedly undescribed species from northern Vietnam which sometimes occur in the pet trade (e.g. HERRMANN 2005). Recent field work of two of the authors (T. SCHÖTTLER and Q. T. NGUYEN) discovered the existence of one of these forms in Bac Giang Province, northern Vietnam (SCHÖTTLER 2003). Our investigations revealed that it indeed represents an unnamed species of the genus Tylototriton which we describe herein.
Material and methods
Specimens examined are deposited at Zoologisches Forschungsmuseum Alexander Koenig (ZFMK). Terminology and description of characters follow STUART & PAPENFUSS (2002). Abbreviations used are as follows: SVL = snout-vent length measured from tip of snout to anterior edge of vent; TTL = total length; TAL = tail length measured from posterior edge of vent to tail tip; TAD = maximum tail depth; HL = head length measured from posterior edge of parotoid to snout tip; HW = maximum head width; EN = eye-nostril distance measured from anterior corner of eye to nostril; IN = internostril distance; AL = anterior limb length measured from point of body insertion to tip of longest toe; PL = posterior
limb length measured from point of body insertion to tip of longest toe. Skeletal characters were assessed using X-ray photography at ZFMK.
Results
Tylototriton vietnamensis sp. n.
Tylototriton asperrimus asperrimus: FLECK, 2003:3 (non UNTERSTEIN, 1930) 216 WOLFGANG BÖHME et al. Tylototriton sp.: SCHÖTTLER, 2003:23; HERRMANN, 2005:21.Echinotriton asperrimus (partim): NGUYEN et al., 2005:9 (non UNTERSTEIN, 1930). Holotype: ZFMK 80637, adult male (Figs. 1- 2), from vicinity of Dong Vanh Village, Luc Son Commune, Luc Nam District, Bac Giang Province, northern Vietnam (21°12' N, 106°40' E, approximately 250-300 m a.s.l.), collected on 23 June 2003 by T. Q. NGUYEN and T. SCHÖTTLER. Paratypes: ZFMK 82971-972, two adult males, from type locality, collected in July 2004 by T. Q. NGUYEN and T. SCHÖTTLER. Referred specimens: ZFMK 82973-75, three larvae, from type locality, collected in July 2004 by T. Q. NGUYEN and T. SCHÖTTLER.
Diagnosis: The new species is diagnosed by the following combination of characters: relatively stout body; head flattened, broader than body; parotoids large, elongated; dorsal skin covered with relatively small warts and glands, three tubercular dorsal ridges; slightly flattened rib nodules, moderately developed; dorsal and ventral tail fin developed; tongue pad lacking a free posterior margin; dorsal colour uniformly greyish tan or brownish in life; venter tan in life; rib nodules slightly orange tan in life; ventral tail fin yellow-orange in life; tips of fingers and toes yellow-orange in life. Comparisons: Tylototriton vietnamensis differs from T. kweichowensis FANG & CHANG, 1932 and T. shanjing NUSSBAUM, BRODIE & YANG, 1995 by a more slender body and by lacking orange or yellow tails and a dorsum with orange-yellow markings. Furthermore, T. verrucosus differs from the new species by its larger size, head shape, and by exhibiting orange or yellowish colour on dorsum, tail and flanks. Tylototriton taliangensis LIU, 1950 mainly differs from T. vietnamensis by head shape, a more slender, elongated body and red flecks at the posterior corner of the Fig. 1. Male holotype of Tylototriton vietnamensis sp. n. (ZFMK 80637) in life. Fig. 2. X-ray photograph of the preserved holotype of Tylototriton vietnamensis sp. n. (ZFMK 80637). 217
A new species of Tylototriton from Vietnam parotoids in adults. In external characters, the new species appears most similar to T. asperrimus, T. hainanensis FEI, YE & YANG, 1984 and T. wenxianensis FEI, YE & YANG, 1984. However, T. vietnamensis differs from T. wenxianensis in the following characters (characters of T. wenxianensis in parentheses): greyish to brownish tan dorsal colour (black), truncate snout in dorsal view (rounded), and moderately large, slightly flattened rib nodules forming lateral ridges (rib nodules and ridges indistinct). In contrast to T. vietnamensis, T. asperrimus exhibits black dorsal colour, very prominent rib nodules, a rounded snout and more prominent bony ridges on head. Tylototriton hainanensis differs by larger size, head much wider than long, black dorsal colour and a more rounded snout.
Description of holotype: Habitus moderately stout; head broader than body. Head slightly sloping in profile. Skull broad with maxillaries oriented angular to body axis. Snout short, truncate in dorsal view, rounded in profile and protruding beyond lower jaw. Nostrils close to snout tip. Upper lips thick, fleshy and overlapping lower lip under eye region. Vomeropalatine teeth in two rows beginning just posterior to the last maxillary tooth at the medium level of the choanae, Fig. 3. Larva of Tylototriton vietnamensis sp. n. collected at the type locality in June 2003 (total length 45 mm).
Fig. 4. Habitat of Tylototrit on vietnamensis sp. n.at the type locality in Bac Giang Province, Vietnam. Fig. 5. Schematic map of Vietnam showing the known distribution of Tylototriton vietnamensis sp. n. in respective provinces: (1) Bac Giang Province (type locality); (2) + (3) Cao Bang Province; (4) Nghe An Province. Question mark indicates locality for Tylototriton cf. vietnamensis in Lao Cai Province (see text for more precise locality data). Stippled lines indicate limitations of provinces. 218 WOLFGANG BÖHME et al. diverging from one another. Tongue with poorly developed tongue pad, lacking a free posterior margin. Thirteen trunk vertebrae (Fig. 2). A low vertebral tubercular ridge, extending from top of head to base of tail. Two lateral rows of larger warts, extending from insertion of forearms to base of tail. Glands and warts relatively small, covering most of dorsal surfaces; venter almost smooth. Parotoids greatly enlarged, slightly projecting backwards. Gular fold absent. Fingers without webbing, toes with basal webbing. Tail laterally compressed; dorsal and ventral tail fin moderately developed; tail tip acuminate in profile. For measurements see
Table 1. In alcohol, dorsal and ventral surfaces brownish tan. Finger and toe tips cream coloured. Tail brownish tan with ventral tail fin being creamy yellow. Cloacal region bordered with cream-yellow. Life colouration differs only by stronger orange-yellow colour of respective body parts.
Variation: There are no obvious differences  in coloration and body proportions between the three male specimens. However, the two male paratypes seem to exhibit more extensive webbing on toes. In life, specimens caught from ponds exhibited considerably lighter dorsal colour (Fig. 1) compared to specimens captured from the forest floor (see FLECK 2003:Fig. 6, as Tylototriton a.  asperrimus). Natural history: Specimens were found in ponds within dense bamboo vegetation in secondary forest. One larva collected in June 2003 had a total length of 45 mm (Fig. 3). At the type locality, larvae were found from June to July in 2003 and 2004. However, in June 2005 only a few males were observed in the ponds, whereas no larvae were present. According to information provided by local scientists, larvae collected in October had almost finished metamorphosis. At that time adults already left the ponds. Presumably, mating and reproduction take place within these ponds (Fig. 4) during the rainy season.
Distribution: So far, the new species is known from four localities in northern and north-central Vietnam (Fig. 5). In addition to the type locality these are: Quang Thanh Commune (22°38' N, 105°55' E) and Thank Cong Commune (22°48' N, 105°44' E), Nguyen Binh District, Cao Bang Province; Pu Hoat Forest, Dong Van Commune, Que Phong District, Nghe An Province (T. SCHÖTTLER pers. obs.). Specimens from Nam Tha Commune (21°55' N, 104°22' E, 850 m a.s.l.), Van Ban District, Lao Cai Province (NGUYEN et al. 2005, T. SCHÖTTLER pers. obs.) exhibit some slight morphological differences and are here tentatively regarded as T. cf. vietnamensis (see discussion). Tylototriton vietnamensis probably also occurs in adjacent southern China and eastern Laos. Etymology: The new species is named after the country of its origin, Vietnam.

 

 

 
Vietnam salamader Tylototriton vietnamensis - Ảnh: Phùng Mỹ Trung
 

Discussion
Tylototriton vietnamensis is the fifth known species of salamander and the third known species of Tylototriton from Vietnam. NGUYEN & HO (1996) reported T. asperrimus from Mau Son and Lang Son areas in northern Vietnam. We have seen photographs of T. ZFMK ZFMK ZFMK 80637, 82971, 82972, male, male, male, holotype paratype paratype SVL 50.1 48.3 53.6 - TTL 119.5 113.9 121.8 - TAL 63.9 62.4 63.1 - TAD 8.0 6.6 7.5 - HL 18.6 17.6 15.3 - HW 16.7 15.7 17.0 - EN 4.0 4.0 4.4 - IN 5.4 5.5 6.1 - AL 16.0 18.7 19.8 - PL 21.3 20.6 20.1 Tab. 1. Measurements of the type series of Tylototriton vietnamensis sp. n. in millimetres (mm). For abbreviations see text. A new species of Tylototriton from Vietnam asperrimus -like living specimens from the nearby Tam Dao area in northern Vietnam and concluded that they display some characters unusual for T. asperrimus: a very stout body shape and a very broad head with very well-developed bony crests. These characters are generally much more developed in T. hainanensis than in T. asperrimus (FEI et al. 1984). Thus, it may not be excluded that some records of T. asperrimus by NGUYEN & HO (1996) actually correspond to T. hainanensis. The geographical distance between Hainan Island and northern Vietnam is less than 400 km and therefore the presence of T. hainanensis in northern Vietnam seems at least possible and respective populations deserve further study. Recently, NGUYEN et al. (2005) reported T asperrimus (as Echinotriton asperrimus) from several localities in northern Vietnam. In a colour photograph, NGUYEN et al. (2005:147) figured a specimen from Lao Cai Province, northern Vietnam. This specimen is very similar to T. vietnamensis in its general habitus, size, flattened head and colouration. However, the dorsal skin appears to be more warty and darker. These slight differences probably display seasonal variation, since individuals in their aquatic phase were found to exhibit relatively smooth dorsal skin and light colouration, whereas specimens caught from the forest floor showed darker dorsal colour and somewhat more warty skin (see paragraph on variation). However, here we tentatively refer to this population as Tylototriton cf. vietnamensis unless more specimens from this population become available. In conclusion, we may suspect that several Vietnamese records referred to as Tylototriton asperrimus (or Echinotriton asperrimus) in the literature are likely to include other taxa like e.g. T. cf. hainanensis (NGUYEN & HO 1996) or T. vietnamensis (FLECK 2003, NGUYEN et al. 2005). ZHAO & HU (1988) suggested that Tylototriton asperrimus should better be placed in the genus Echinotriton based on the sharptipped ribs which may penetrate the skin at their apices and because of a reproductive mode with terrestrial egg deposition (compare NUSSBAUM & BRODIE 1982). NUSSBAUM et al. (1995) provided convincing arguments for transferring the species again to Tylototriton and this is also corroborated by recent genetic studies (LARSON et al. 2003). As mentioned above, Tylototriton vietnamensis shares some external characters with T. asperrimus, but its general habitus appears quite different. It does not exhibit extraordinarily sharp-tipped ribs and penetration of the skin could not be observed in the specimens studied by us. The relationships of T. vietnamensis remain unknown at this stage, however, both species might be related.
Acknowledgements
We are indebted to NGUYEN VAN SANG (Institute of Ecology and Biological Resources) who first found the new species in Bac Giang, as well as to RAOUL BAIN (American Museum of Natural History), NGUYEN MANH HA (Center for Natural Resources and Environment Study) and THOMAS ZIEGLER (Zoologischer Garten Köln) for providing the map and unpublished information. Furthermore, we thank DUONG XUAN BANH (Deputy Director of Bac Giang Forest Protection Department) for valuable help with research permits for the Bac Giang Province and KLAUS BUSSE (ZFMK) for helping to prepare the X-ray photograph.

 

 

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