Echinotriton chinhaiensis (Chang, 1932)
Chinhai Spiny Crocodile Newt
© 1999 Max Sparreboom (1 of 17)
Author: Axel Hernandez
Echinotriton chinhaiensis (CHANG 1932)
Diagnosis and taxonomyThe holotype (SSCN H121) from Chenwan (=Chengwuan), Chinhai (=Zhenhai), Zhejiang Province, China, about 32 km southeast of Ningbo City, was lost, and a neotype from Ruiyansi (about 5 km from Chengwuan), alt. 140 m (ZMNH 780381) subsequently designated by CAI & FEI (1984). Echinotriton chinhaiensis is a stout salamander with a flattened body and head, and a series of ca. 8-12 prominent spiny warts (dorsolateral glandular warts penetrated by distal rib extremities). The head is broad and triangular in shape in dorsal view. The skin is granular. Its vomero-palatine teeth are arranged in two longitudinal series in V-shape, meeting in the front. It is uniformly dark brown or black on the dorsal and ventral sides, with only the underside of the tail, cloacal region, and the soles of the feet being colored yellowish orange. 5th toe developed normally. Total lengths (TL) are 12.4-15.1 cm in females and up to 10.9 - 13.9 cm in fully-grown males (FEI et al. 2012). There is no obvious sexual dimorphism; in both sexes, the cloacal opening forms a longitudinal slit. When slightly opened, the cloaca of the female will be found to be smooth on the inside, though, whereas that of the male will be more rugose. When carrying eggs females have a distended abdomen. In the male, the vent is swollen during the mating season (CHANG 1932, 1936, CAI & FEI 1984, YE et al. 1993, SPARREBOOM 2014, HERNANDEZ 2016d). Genetic diversity within the only known population is insignificant (XIE 1999). E. chinhaiensis is morphologically relatively close to E. andersoni (ZHAO & HU 1988), but differs from this species in that it has no rows of warts running on each side of the spinal crest supported by the ribs.
DistributionE. chinhaiensis is only known from the Ruiyansi Forest Park (=neotype) and two neighboring valleys of Ningbo City to the east: “Chenwuan” (=Chengwan =type locality; CHANG 1932, FROST 2016) and Qiushan in the Beilun District, Zhejiang Province, China. One more locality was discovered in the Qiushan Valley in the course of a vertebrate survey in Zhejiang in 1999 when two females were found at the edge of a small puddle that was entirely covered with dense vegetation. The species has not been reported from the type locality for many years and could not be found during the survey in April of 1999 either. It must therefore be considered extremely rare. A new population was discovered by the author in the Shashan Mountains (Ningbo County) in 2014, but this area became a construction site and 80% of it was destroyed in 2015.
Habitat, ethology and ecologyAccording to our ecological studies (HERNANDEZ 2015c, 2016a,c,d, HERNANDEZ et al. in press), Echinotriton chinhaiensis is is a microendemic species from Southeastern China restricted to low elevations (between 100 to 215 m a.s.l.). Its habitat consists of forest patches between rice paddies. This biome is classified as ‘warm perhumid deciduous evergreen broad-leaved forest’ (LIN 2014) and mainly composed of trees of the family Fagaceae (stone and ring-cupped oaks, genera Lithocarpus and Cyclobalanopsis), and bamboo thickets (Phyllostachys spp.) up to 30 m tall, combined with shrubs (including Camellia sinensis and Osmanthus fragrans) and perennial grasses (FANG et al. 2011, FLORA OF CHINA 2015). The species is found in a small, forested area in a hilly habitat in eastern Ningbo 100 to 200 meters above sea level. Here, the vegetation is dense and composed of three strata: A top stratum of evergreen trees, an intermediate one of shrubs, and a bottom stratum of grasses. This floral diversity thrives on a rich soil with a thick layer of vegetal litter in which terrestrial animals can hide. The soil is very moist throughout the year and the newts are encountered in the immediate vicinity of small subpermanent ponds whose water has a pH of between 6 and 7. Although frequent rains will feed these few ponds almost continuously, they remain shallow (XIE et al. 2000). Temperatures at these elevations are relatively high and can reach 28.5 °C on hot summer days, and winter temperature average 10.0 to 15.5 °C from November through March. The relative humidity is 76 to 88% at the type locality in summer (HERNANDEZ 2016d). The newts here feed mainly on earthworms, small snails and scolopenders (CAI & FEI 1984). The females become active when they are about to deposit their eggs, but males are scarce and inconspicuous. Chinhai spiny crocodile newts exhibit a particular defense posture when facing a predator: They will bend the body, legs and tail, presenting their protruding spines as ready to piercing the skin (BRODIE et al. 1984, CAI & FEI 1984, RAFFAËLLI 2013, SPARREBOOM 2014).
ReproductionOviposition takes place when the first storms herald the arrival of the monsoon during the last 20 days of April according to THORN (1968) or in late March according to XIE et al. (2000). SPARREBOOM et al. (2010a) observed the courtship of this species, which takes place on land with the male approaching the female and depositing several spermatophores while excreting mucus on the substrate that has the appearance of hoarfrost. The pair will engage in circling movements during which the female remains orientated towards the male’s cloaca and picks up his spermatophores with hers. The number of eggs per clutch average 72 to 94, and egg diameters range from 3.3 to 3.5 mm. They are deposited near ponds. Hatching larvae will then head for the water using rivulets from rain and propelling themselves forward with the force of their tails. They can survive for 3-4 days in the moisture-saturated humus before they have to reach the water. Metamorphosis generally begins after 110 days of development when the larvae have grown to 34 - 36 mm (THORN & RAFFAËLLI 2001) and will take another 55 - 88 days (XIE et al. 2001). In captivity, sexual maturity is attained at about 5 to 6 years of age. In general, this species’ reproduction follows the pattern of other species of the genus (see E. andersoni). MAX SPARREBOOM described that the species reproduced in three ponds in the Ruiyansi Forest Park from June to September in 2008. Revisiting these ponds in July of 2015, I found them to be surrounded by destroyed habitat, and very few larvae were surviving a growing invasion of predators such as dragonfly larvae that were proliferating probably due to global warming.
Status, threats and conservationEchinotriton chinhaiensis is critically endangered. The species is considered as one of the most endangered salamanders species of the world (HERNANDEZ 2016c,d). It is distributed within an area of just 51 km². A population census in 1999 revealed 370 adult individuals to live in the Ruiyansi Forest Park east of Ningbo, Zhejiang (XIE 1999, SPARREBOOM 2014), and 300 to 400 adult individuals are thought to exist in total by LIU et al. (2010) or 200 according to more recent observations (HERNANDEZ 2015a, 2016a,c,d). Some young specimens from a conservation program headed by Professor XIE FENG at the Chengdu Institute of Biology in Sichuan were reintroduced, but many individuals were lost between 2004 and 2005 and again in 2013. The species is threatened mainly by the loss of habitat. According to MAX SPARREBOOM, two individuals were offered for sale by a Japanese pet store for $ 1,400, but could be recovered in time by Chinese researchers and added to their captive breeding colony; this offer made the Ningbo authorities aware of illegal collection taking place. Although the two valleys, Chengwan and Qiushan, might still harbor as yet undetected populations, the expanding cities in the region leave little hope for this species.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Jun 2023.
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