Panha’s Crocodile Newt, Loei Crocodile Newt
Species Description: Nishikawa K, Khonsue W, Pomchote P, Matsui M. 2013. Two new species of Tylototriton from Thailand (Amphibia: Urodela.Salamandridae). Zootaxa 3737: 261-179.
© 2017 Axel Hernandez (1 of 9)
Author: Axel Hernandez
Tylototriton panhai NISHIKAWA, KHONSUE, POMCHOTE, & MATSUI 2013a
Diagnosis and taxonomyThe original description of Tylototriton panhai is based on an adult female holotype (THNHM 2800) collected in the Phu Ruea National Park, Loei Province, northeastern Thailand (17°29’59’’N, 101°20’30’’E) at 1,183 m a.s.l. in May of 1998. Its species name was chosen in honor of Professor SOMSAK PANHA (Chulalongkorn University) who is an active nature activist and fieldworker. Tylototriton panhai is the most differentiated species of the subgenus Yaotriton and forms a clade with T. vietnamensis. It is characterized by the presence of 13 large and prominent dorsolateral glandular warts; wide dorsolateral bony ridges on the head; spine not quadrate; vertebral ridge distinct and not segmented; skin rough with fine granules; limbs long and thin; tips of fore- and hindlimbs greatly overlapping when adpressed along body; tail thin; dorsal head, upper and lower lips, parotoids, vertebral ridge, dorsolateral glandular warts, tips of fingers and toes, margins of cloacal slit, and dorsal and ventral edges of tail yellow, orange, to reddish brown (NISHIKAWA et al. 2013a), varying with the population. The sharply contrasting dorsal color pattern is reminiscent of that in members of the subgenus Tylototriton, from which T. panhai differs, however, by having wide dorsolateral bony ridges on the head, and the limbs and tail being black. From other members of the subgenus Yaotriton, it is distinct by having conspicuous yellow to reddish brown markings on the head, trunk, and tail edges (vs. a black body except for tips of fingers and toes, margins of vent, and ventral edge of tail in all other species). Males have a less massive body than the females, but sexual dimorphism is otherwise poorly expressed. During the breeding season, the cloacal fissure is a slightly inflated oval slot in females whereas males will have a rounded and slightly protruding orifice.
According to various field studies (POMCHOTE et al. 2008, NISHIKAWA et al. 2013a) and my observations (HERNANDEZ 2016a,b), three geographic groups of T. panhai can be distinguished morphologically, but two of these groups are not genetically distant enough to separate them as valid species (Types I & II) (HERNANDEZ, POYARKOV & PAUWELS unpubl. data 2015). They are sufficiently divergent to underscore their importance in terms of conservation, however. These morphological groups are characterized as follows:
T. panhai Type I : This type is known from the Phu Luang Wildlife Sanctuary and Phu Ruea National Park, both in Loei Province. The female holotype belongs to this type. It is characterized by having protruding orange/yellow dorsolateral glandular warts, a black body, and well-developed cephalic edges especially in females. Type I reaches a moderate TL of up to 15 cm in males and 16 cm in females.
T. panhai Type II : This type is restricted to Phu Suan Sai / Na Haeo (Dan Sai District) and the adjacent mountains in Laos (Sainyabuli, Botene). The exact location is not revealed here for conservation reasons. Specimens from this locality grow to a longer total length (>16.5 cm in males), have smaller orange/yellow dorsolateral warts, and the body and limbs are pinkish cream to brownish in ground color. This type shows a bright cream and orange stripe on the side of the tail especially during the breeding season. The colors of individuals of this population may vary with the season from a cream and orange general coloration with small dorsolateral warts that sometimes tend to be bright yellow during the breeding season to a generally darker dress, dark brown to blackish, after September during the terrestrial phase (pers. obs.).
T. panhai Type III : This type is restricted to the mountain ranges of Hin Rong Kla (Phitsanulok) up to Phetchabun Province. It also occurs in the Nam Nao National Park, but could not be confirmed from there during my field survey in 2014. Its range is the smallest of the three forms observed and the most southern of all species of Tylototriton. Its population suffers from increasing tourism in the Phu Hin Rong Kla National Park and the accompanying pollution of its habitats. Type III is characterized by a dark reddish brown coloration with poorly developed, reddish dorsolateral warts. The Males of this population can reach a maximum TL of 13.8 cm and females 14.5 cm. Distribution As far as is currently known, Tylototriton panhai occupies the southernmost parts of the total range of its genus, extending from Phitsanulok, Phetchabun and Loei Provinces in northeastern Thailand, south to Luang Prabang, and east into Laos (Sainyabuli Province, Botene District). I also recorded these newts from Phu Khe, Doi Phu Kha, Doi Phu Wae, and Doi Phi Pan Nam, which are all situated in the same mountain range in Thailand (HERNANDEZ 2016b). This range includes four large protected nature reserves in Thailand, i.e., the Phu Hin Rong Kla National Park in Phitsanulok and Phetchabun Provinces (Type III), Phu Luang Wildlife Sanctuary and Phu Ruea National Park, Loei Province (Type I), and Phu Suan Sai National Park / Na Haeo National Park in Loei Province. My review of Thai literature and examination of specimens in the Chulalongkorn Natural History Museum collection furthermore identified new localities in Phu Kradung, Thung Salaeng Luang or Nam Nao National Park (Phetchabun), but while my subsequent surveys have not confirmed the presence of these newts there, their occurrence was in the recent past confirmed through photographic records made by amateurs and the testimonies of local people.
Habitat, ethology and ecologyThis species is a niche specialist that occurs in mixed deciduous, dry dipterocarp, dry evergreen, and hill evergreen forests at moderate elevations of 1,185 to 1,650 m a.s.l.. The soils in these areas are sandy loam, mainly composed of smectite and kaolinite (HERNANDEZ 2016b). My study found Dipterocarpaceae forests and surrounding grassland to constitute the main habitat in Loei province. In the Phu Hin Rong Kla National Park, it is characterized by dense vegetation of various bamboos, Musa spp., but also Dipterocarpus alatus, Hopea ferrea, Hopea oborata, Anisoptera cochinchinensis, Dalbergia oliveri, and Chukrasia venlatina. The species is terrestrial outside, and aquatic during, the rainy season (beginning in early May) when it will be found in temporary ponds (usually 20 to 40 cm deep) or slow streams flanked by grasses and Musa siamensis and Phyllostachys viridiglaucescens. The ground temperature is around 24.0 °C during the day during the monsoon season and 10.0 to 15.0 °C on average from November through January. Indeed, from May to October, the monsoon brings heavy rains of 150 - 200 mm/month in Phu Hin Rong Kla. I noticed that the species appears to be more common beyond 1,200 m a.s.l. and found several males in small stagnant pools with a bottom of silt and rotting leaves, but also in small streams at 1,250 m a.s.l. in Phitsanulok Province and at 1,500 m a.s.l. in Thap Boek in Phetchabun (HERNANDEZ 2016a,b). Air temperatures were taken in July and August and varied from 27.0 °C during the day to 19.0 °C at night, and a water temperature of 22.0 °C was recorded in July. High biodiversity coexists with the species in these waters, comprising mollusks, larvae of various insects (dragonflies, mayflies), and crabs that will sometimes constitute prey. The tadpoles of Limnonectes gyldenstolpei form part of the diet of adults in Phitsanulok and Phetchabun during the mating season. During the dry season, the newts find shelter in the rainforest composed mainly of Gigantochloa cochinensis, banana and Ficus geniculata / Ficus retusa (whose fallen leaves form refuges on the ground and an important source of moisture when they break down), but also Garcinia speciosa, Acronychia pedunculata, Styrax benzoid, Anacolosa ilicoides, and Chionanthus sutepense. This species never strays far from the temporary ponds and small permanent streams that keep humidity levels fairly constant at 80 to 90%. However, some populations have been observed in a different habitat, i.e., karst in open grasslands at Lan Him Phom (Phitsanulok) and Phu Ruea, which are home to one of the largest populations of T. panhai. This habitat consists of small canyons surrounded by moss- flanked springs that feed small streams in deep crevices and caves at an elevation of 1,200 m a.s.l. in northern Phu Ruea where the holotype was discovered in 1998. The temperature here is 20.0 to 25.0 °C for most of the year and a colder period of 8.0 to 12.0 °C persists from November through January. The newts spend the cold season hidden underground or under fallen leaves where humidity remains at 40-60% (Phu Hin Rong Kla, Doi Pui, Doi Suthep Phu Ruea). Only the populations in the Lao border region (Type II) live at higher temperatures throughout the year (27.0 °C during the day and 24.0 °C at night). Disturbed or captured specimens may emit a soft thudding sound (WONGRATANA 1984, HERNANDEZ 2016a,b).
ReproductionThe breeding period can shift from one year to another, depending on climate, ambient humidity, and the first heavy precipitations, suggesting that the onset of the rainy season is the key factor to trigger reproduction in nature. Normally, the first rains arrive in May, which is when the males are the first to enter small ponds and shallow streams with a bottom covered with fallen leaves and surrounded by grass. They will then wait for the females to follow suit approximately two months later. The latter will stay in the water only for 10 to 15 days. In captivity, it will be necessary to gradually fill the aquatic section over several days while wetting the terrestrial part and raising temperatures. Rain systems like those used for propagating Dendrobates spp. or Bolitoglossa spp. can perfectly emulate such a rainy season and therefore useful for encouraging reproduction in T. panhai, too. A clutch of eggs of the Phu Suan Sai form (Type II) was found in the first week of August. These eggs ranged from 2.0 to 2.5 mm in diameter. Females deposit 15 to 20 eggs either near or in ponds, attaching them to twigs, plants and even tree roots, sometimes more than 30 cm above the ground (Phu Suan Sai; pers. obs.). This apparently serves to protect them from predators such as crabs, water snakes and freshwater turtles. The hatchling larvae will then be washed down the roots and into the nearest water body by heavy rains. The larvae are yellowish cream to orange dorsally and tend to become brown to black before their metamorphosis, with the dorsal ridge, parotoids, snout and ventral parts turning yellow to orange. Exondation has been observed after 3 months at 22.0 °C between 17 August and 15 November 2015. As far as the larval diet is concerned, their main food in the natural environment are Moina macrocopa (a species of Asian daphnia) and tadpoles of Limnonectes gyldenstolpei. Larval cannibalism is not uncommon in larvae from 15 to 25 mm both ex and in situ, but will subside beyond this size range. Losses can be forestalled by keeping the larvae individually in containers furnished with Java moss and a small bubbler to properly oxygenate their water (HERNANDEZ 2016b). Metamorphs were fed with Drosophila spp. and small crickets fortified with vitamins (HERNANDEZ 2016b). Sexual maturity is reached at an age of 4 years in the wild (KHONSUE et al. 2010).
Status, threats and conservationThe species has a very limited range and is protected by Thai law (as T. uyenoi), but populations nevertheless suffer from tourism, deforestation, global warming, collecting for traditional Thai medicine (Hmong drugs), and farming in the Phetchabun part of the range. In the past, T. panhai and T. uyenoi have long been associated with evil, bad omens, incarnations of demons, or witchcraft and senselessly pursued by villagers of the Kachin, Karen, Hmong and also Isaan peoples. In the ancient times of the Sukhothai, Ayutthaya and Lannathai Kingdoms, villagers killed these newts in the belief that there were evidence of demonic acts launched by a malicious spirit and the return of reincarnated souls. On the other hand, they were valued from time to time as curing high fever. In the provinces of Loei and Phetchabun in the northeast of Thailand, the Hmong ("people of the northern mountains") and Isaan sometimes dry these animals and mix them with plants for making traditional medicine. Unfortunately, these ancestral beliefs seem to persist in some regions and now add pressure on the already small and relatively fragmented populations. Actually, the original habitat of T. panhai has disappeared owing to shift-farming practices and illegal logging and the species is now limited to isolated mountainous areas without human disturbances. I suggest that its status be reviewed and upgraded to “Endangered”.
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Citation: AmphibiaWeb. 2020. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Jan 2020.
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