Ziegler's Crocodile Newt
Species Description: Nishikawa K, Matsui M, Nguyen TT 2013 A new species of Tylototriton from northern Vietnam (Amphibia: Urodela: Salamandridae). Current Herpetology 32: 34-49.
© 2013 Kanto Nishikawa (1 of 2)
Author: Axel Hernandez
Tylototriton ziegleri NISHIKAWA, MATSUI & NGUYEN 2013b
Diagnosis and taxonomyThe original description designated an adult male holotype (VNMN 3390) found at 1,357 m a.s.l. on Mt. Taboc Ban Thang (Thang Village), Thung Vai Municipality Quan Ba District, Ha Giang Province, northern Vietnam in April of 2012. Its name is a tribute to THOMAS ZIEGLER (Cologne Zoo, Germany), who has been contributing greatly to the study and conservation of biodiversity in Vietnam. This species corresponds to the populations of the Vietnamese provinces of Ha Giang and Cao Bang (Quang Thanh) previously identified as T. cf. vietnamensis. Phylogenetically, T. ziegleri forms a clade with T. hainanensis and T. notialis. It is a medium- sized species in which males can reach 13.2 and females 14.2 cm TL. It has a rough skin, 15 to 16 dorsolateral glandular warts, very pronounced cephalic edges, parotoids and spinal ridge, a large head (but smaller than that of T. hainanensis), large eyes, elongated limbs, a thin tail, black upper side, and a blackish gray underside. Females are larger than males and sport a distended abdomen during the breeding season, whereas males tend to have more robust-looking limbs than females. The tails of females are relatively shorter than in males, and their cloacal slit is also shorter. In life, Tylototriton ziegleri is blackish above, fingertips, toetips, and parts of the palms and soles being bright orange. In preservative, the dorsal coloration will fade to a light brown and the orange areas to a cream color (NISHIKAWA et al. 2013b). In life, the larvae are uniform yellowish brown dorsally, while the ventral side is translucent and close to white. Finger and toes are yellow. Golden spots cover the dorsal sides of the head and trunk, the sides of the body, end of tail, and the chest. In preservative, the yellowish brown dorsal color fades to light brown and the golden spots to white (NISHIKAWA et al. 2013b).
Ha Giang Province harbors a population of these newts that stand out by their slightly prominent orange warts, grainy skin, and a large head, and more field studies are needed to understand the species’ diversification. Male specimens collected at different localities are generally similar in morphology except for some specimens from two locations in Cao Bang that have more sparsely scattered granules, sometimes reddish rib warts, and a smoother vertebral ridge.
DistributionThe distribution range of this species has not yet been clarified. Aside from the type locality on Mt. Taboc Ban Thang (Thang village), other localities are known from Vi Xuyen District, Ha Giang Province, and Bao Lac, Quang Thanh, Mt. Nui Pia Oac, Cao Bang Province. This species is also present in Jingxi County, southern Guangxi Province, China, near the Vietnamese border from where T. hainanensis was reported in the past. However, this type seems to correspond to another species of the T. asperrimus complex referred in my study as T. cf. asperrimus « Baise » (Clade B). In 2015, the current author furthermore found four adult specimens in a densely canopied forest with several small ponds in a mountainous area in southern Jingxi at about 950 meters.
Habitat, ethology and ecologyZiegler’s crocodile newt is generally found in dense subtropical evergreen forests with patches of grasses, woody shrubs and bamboos at 885 to 1,360 m a.s.l., but also at higher elevations (1,700 meters on Mt. Tay Con Linh, Ha Giang Province). Its habitats are characterized by a warm- temperate climate with dry winters and hot summers with abundant rainfalls. The species occurs in slow-flowing streams and temporary pools of 30 - 50 cm deep during the breeding season, and will hide under rocks and in other cavities during its terrestrial phase. Paramesotriton guangxianensis (in Cao Bang) and P. deloustali (in Ha Giang) occur in sympatry with T. ziegleri, but inhabit cooler streams at higher elevations in some mountain ranges.
ReproductionThe newts seek out puddles and small ponds when rains commence in April to May. Their spawn is deposited on land, some 50 - 60 cm from the waterline, from where heavy rains will wash hatchling larvae down the slippery banks into the water. Metamorphosis takes place from July.
Status, threats and conservationThe loss of habitat through destructive anthropogenic activities around ponds is the main threat to this species (NISHIKAWA et al. 2013b). It is protected as per the Vietnamese Red Data Book, but its IUCN status should be reviewed considering its small distribution range. I suggest a status of “Endangered”.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 10 May 2021.
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