Echinotriton chinhaiensis (Chang, 1932)
Chinai Newt (English), Chinhai Spiny Newt
IUCN (2010) lists this species as critically endangered. The one population of Echinotriton chinhaiensis that has been followed over the years is in Ruiyansi Forest Park, near the city of Ningbo in the province of Zhejiang. Suitable habitats featuring a combination of characteristics such as sufficient cover for the eggs and appropriate water bodies for the development of larvae are rare. Road construction and deforestation contribute to fragmentation of the scarce habitats and to a decrease in populations and number of individuals; pollution of the breeding habitat is a serious threat (Xie et al., 2000). Cai & Fei (1984) and Fei (1992) signaled that the habitat in the valley was rapidly decreasing, giving way to cultivation of tea plantations, orange orchards and other small scale agriculture. The one population that was known, that of Ruiyansi, looked still relatively healthy but was isolated and vulnerable, and had to be considered endangered. As a consequence, in 1988 E. chinhaiensis was listed in the grade 2 category of major state protected wildlife (Zhao, 1998), which implies that since that time the capture and handling of this salamander were licensed by the state government. The species is protected by law in Zhejiang (Huang et al., 1990).
In 1999, artificial ponds have been created near the known breeding ponds in Ruiyansi Forest Park. These ponds were colonized by salamanders one year later (Sparreboom et al., 2001), but the population trend remains decreasing. Attempts have been made to prevent farmers from dumping pollutants and cleaning their equipment in the ponds. A recent survey in 2008 at Ruiyansi revealed that one of the four breeding ponds had been destroyed, and the total number of females that came and laid eggs in the ponds had fallen to 47, less than 50% of the numbers found in 1998–2000 (Liu et al., 2010). This decrease is probably due to construction work, tourism and two heavy typhoons in 2007.
Echinotriton chinhaiensis is closely related and very similar to the Japanese sister species E. andersoni (Zhao & Hu, 1988), but differs from that species in that it lacks the rows of secondary warts running on each side of the vertebral crest, between vertebral column and the row of primary warts, supported by the ribs. It has only one epipleural process on each of the ribs 2 to 4; the fifth toe is normally developed; it has 5 metatarsals and 9 tarsals (Cai & Fei, 1984). Genetic diversity is low, but not significantly (Xie, 1999).
The mitochondrial genome has been sequenced by Zhang et al. (2008).
Echinotriton chinhaiensis is a stout salamander with flattened body and head, and with a series of ca 12 conspicuous knob‑like, porous lateral glands. Head broad and triangular in shape. Bony ridges are not pronounced on head. A triangular projection present posterior to the mouth, corresponding to the unique quadrate hook on the skull (Fei et al., 2006). Skin granular. Vomeropalatine teeth in V-shape, arranged in two longitudinal series, meeting in front. Tail much shorter than snout-vent length. No obvious morphological distinction between the sexes. In both sexes the cloacal opening consists of a longitudinal slit. When slightly opened, the cloaca of the female is smooth on the inside, whereas that of the male is more rugose. When carrying eggs, females have distended abdomens. In the male the vent is swollen during the mating season. Color uniformly dark brown or black on the dorsal and ventral sides, with only the posterior margin of the paratoid gland, the projection behind the mouth, underside of the tail, cloacal region and palms and soles colored yellow-orange. Some individuals have the orange color on their knob-like lateral warts (Fei et al., 2006).
All measurements are from Fei et al. (2006).
Male (14 specimens). Total length: 109–139 mm; snout-vent length: 61–81 mm; head length: 14–17 mm; head width: 14–20 mm; forelimb length: 19–22.5 mm; hind-limb length: 19–21.5 mm.
Female (10 specimens). Total length: 124–151 mm; snout-vent length: 75.5–82.2 mm; head length: 15.5–18 mm; head width: 20–23 mm; forelimb length: 22.5–25 mm; hind-limb length: 22.5–26 mm.
Ecology and Distribution
Echinotriton chinhaiensis is known only from the type locality and two nearby valleys east of the city of Ningbo (respectively Chengwan, Ruiyansi and Qiushan, district of Beilun, province of Zhejiang, China), where it inhabits a forest area 100-200 m above sea level (Fei et al., 1999). Over the last 20 years, the species has been reported only incidentally from the type locality.
Typical spawning habitats around the ponds to which the females migrate are characterized by a combination of features: Dense plant cover around the ponds. Vegetation composed of an upper layer of evergreen broad-leaved trees, a middle layer of shrubs, and a lower layer of grasses, creating a dark and humid habitat. The ponds are semipermanent with a pH value of 6 to 7. The water bodies are small and shallow, receiving water mainly from rain. The only three ponds left after 2008 are 6–9 square meter with a maximum water depth of 30–40 cm (Liu et al., 2010). The egg-laying areas consist of slopes and flat ground directly bordering the ponds; the surface consists of loose soil and stones and is invariably covered by a thick leaf litter (Xie et al., 2000).
The population in Ruiyansi Forest Park probably consists of no more than ca. 370 adult animals (Xie, 1999). Both males and females of this salamander lead a largely hidden terrestrial life and are difficult to observe outside the breeding season. They are inactive during the day and very slow-moving when active. Hibernation takes place from November to March. Food consists of earth worms, snails and Scolopendridae (Cai & Fei, 1984).
In the reproductive season, only the females move to the oviposition sites. Males are found rarely. Mating takes place on land and has only been observed under captive conditions (Sparreboom et al., 2001). The male approaches the female and deposits several spermatophores on land. The couple makes a circular movement, during which the female keeps oriented towards the cloaca of the male. The male excretes a thin mucous thread from his cloaca on the substrate. In the course of the circular movements the female is led over the spermatophore. Eggs are laid in the humus or under rotting leaves in places close to ponds, puddles and springs (mostly 40-50 cm from water). After 20–29 days larvae hatch on land and wiggle or are washed into the pond (Fei et al., 2006). They can survive 3 to 4 days on land. The breeding season extends from late March to late April (Xie et al., 2000). Both migration to oviposition site and hatching of the larvae appear to be related to rainfall. Larvae stay in water for 58–90 days and metamorphose into 4 cm long juveniles.
The Chinhai Salamander has been captive-bred on a small scale in an outdoors enclosure at the Chengdu Institute of Biology. Observations on captive animals suggest that these animals do not become mature until they are at least 10 years old and are likely to live for at least 20 years (IUCN, 2010).
- Tylototriton chinhaiensis Chang, 1932, Contrib. Biol. Lab. Sci. Soc., China, Zool. Ser., 8: 201. (synonym)
- Echinotriton chinhaiensis Nussbaum and Brodie, 1982, Herpetologica, 38: 322. Fei, Ye, Huang, Jiang, and Xie, 2005, Illust. Key Chinese Amph., : 44. (synonym)
- Tylototriton (Echinotriton) chinhaiensis Zhao and Hu, 1984, Stud. Chinese Tailed Amph.: 16. (synonym)
- Echinotriton chinhaiensis Cai and Fei, 1984, Acta Herpetol. Sinica, Chengdu, N.S., 3 (1): 71. Zhao, 1990, in Zhao (ed.), From Water onto Land, : 219. (synonym)
- Pleurodeles (Tylototrion) chinhaiensis Risch, 1985, J. Bengal Nat. Hist. Soc., N.S., 4: 142. (synonym)
- Pleurodeles (Echinotriton) chinhaiensis Dubois, 1987 "1986", Alytes, 5: 11. (synonym)