Echinotriton maxiquadratus Hou, Wu, Yang, Zheng, Yuan & Li, 2014
Mountain Spiny Crocodile Newt; Gao Shan Ji Yuan (Chinese)
|Species Description: Hou M, Wu Y, Yang K, Zheng S, Yuan Z, Li P 2014 A missing geographic link in the distribution of the genus Echinotriton (Caudata: Salamandridae) with decription of a new species from southern China. Zootaxa 3895: 89-102.|
© 2020 Axel Hernandez (1 of 7)
Author: Axel Hernandez
Echinotriton maxiquadratus HOU, WU, YANG, ZHENG, YUAN, LI 2014
Diagnosis and taxonomyThis unique species was defined after a single holotype (SY20131101ENT), an adult female of 12.9 cm in length collected in southern China in November of 2013. E. maxiquadratus is clustered at mtDNA level with E. chinhaiensis, which occurs geographically separated by 600 - 1,000 km. This cryptic species is characterized by a flat body covered with tubercles of various sizes, and a series of 8 - 10 prominent spiny warts. The mountain spiny crocodile newt is a moderately large species that can reach 16 cm in maximum total length (TL). Females are larger than males and have a more massive body with a distended abdomen when gravid. Males do not normally exceed 14.5 cm in TL. Echinotriton maxiquadratus can be distinguished morphologically from its congeners by the following combination of characters: a trapezoid projection behind the mouth corresponding to the quadrate spine (triangular projection in the other two species); only a single row of 8 - 10 dorsolateral prominent rib warts on each side of body (another 1 – 3 rows of smaller warts between the lateral warts and the vertebral ridge in E. andersoni); 5th toe developed normally (rudimentary in E. andersoni); tip of longest finger exceeds tip of snout when forelimb is extended rostrally (approaching nostril in E. chinhaiensis); skin tubercles conical (ridge-like in E. chinhaiensis); 8 - 12 white to yellowish costal spiny warts forming asperities at the extremities of the ribs; a wide spinal ridge is present; and black, with the ends of the lateral edges of the fingers and toes, cloaca, and the lower edge of the tail being orange-yellow.
DistributionUnlike the other two species of Echinotriton, E. maxiquadratus is native to two mountains in southeastern China. The second locality is new and was found later in July 2015 during our field study. The exact localities have not been disclosed in an effort to protect the critically endangered species from poaching (HOU et al. 2014, HERNANDEZ 2016c,d).
Habitat, ethology and ecologyAccording to ecological studies (HERNANDEZ 2016c,d, HERNANDEZ et al. in press), Echinotriton maxiquadratus is the only species of its genus that lives at moderate elevations (1,145 − 1,450 m a.s.l.) in mosaic habitats of grassland, tea plantations and forest, crisscrossed by small streams and interspersed by ponds. This biome is generally classified as ‘subtropical perhumid evergreen broad-leaved forest’ (LIN 2014). It contains a highly diverse assemblage of trees (5 − 15 m tall), including species of the family Altingiaceae, Araliaceae, Fagaceae (oaks and beeches), Hamamelidaceae (witch hazels), Lauraceae (laurels), and Theaceae (FANG et al. 2011). These forests have a dense understorey of giant grasses, shrubs and smaller trees (2 − 10 m tall) dominated by Adinandra millettii, Dendrobenthamia hongkongensis, Eurya chinensis, Ficus variolosa, Helicia kwangtungensis, Itea chinensis, Miscanthus floridulus, Photinia prunifoli, Symplocos sp., and perennial herbs (10 − 100 cm tall) such as Hypericum attenuatum and Veratrum schindleri (FANG et al. 2011, FLORA OF CHINA 2015). The female holotype was discovered at 1,400 m a.s.l. on a mountain, more exactly under a heap of stones in a grassy area with rhododendrons and melastones in the presence of small marshes and ponds. At this locality, the newts were absent from the open grassland between swamps and evergreen broad- leaved forest. The climate on this mountain is relatively stable in contrast to lower regions where temperatures can exceed 40.0 °C on hot summer days. It is subtropical due to the elevation of the central and southern valleys. Annual average temperatures are around 19.0 °C, with winter values that can drop as low as 0 °C and moderate summer temperatures of about 20.0 to 26.5 °C. Fog is prevalent during the night and morning hours all year round and so provides the moist conditions required by amphibian life. The average annual rainfall amounts to about 2119 mm, with most rain falling in the hot season and keeping relative humidity levels at 85% or above (HERNANDEZ 2016c,d). Many neighboring mountains offer similar conditions and could be home to other, as yet undiscovered populations. A new locality was discovered by the author in July 2015. Adult individuals and larvae were found between 1,240 and 1,320 m a.s.l. The air temperature was 19.6 °C at night and 26.6 °C during the daytime, that of the water 21.2 °C (with larvae), and humidity 79%.
ReproductionThree reproduction sites were discovered for the first time in July of 2015 on the new locality located 100 km away from the type locality (HERNANDEZ 2016a,c,d). They were vegetated by Sphagnum moss and grasses, and populated by larvae of 1.6 to 4.8 cm in length (TL), which suggested them to be approximately 1 to 1.5 months old when supposing a growth rate similar to E. chinhaiensis. Oviposition takes place at the beginning of May during first rains. Some days later, eggs are deposited in mass on leaf litter at 0.30 cm to 1 m. away from water points.The number of eggs per clutch average 22 to 40, and egg diameters range from 3.8 to 4.2 mm. The hatching larvae measure 16 mm in length (TL), are yellowish in color and turn black with age. pH recorded at the spawning site was between 7.3-7.6 (HERNANDEZ 2016d).
Status, threats and conservationE. maxiquadratus must be considered critically endangered based on personal observations even though the current size and state of its population has not been investigated in a comprehensive scientific manner. Only ten specimens were found at the type locality within a year after the discovery of the female holotype, and nobody has found the species there since 2013. The new locality discovered by the author also appears to be very sparsely populated to say the least. This species is truly a living fossil and certainly one of the most endangered species of terrestrial urodeles, on par with E. chinhaiensis. Current knowledge suggests it to occur only in two very small areas of approximately 10 - 20 km² with populations of less than 100 - 150 individuals (HERNANDEZ 2016a,c), and these are under pressure from tourism, human presence, and habitat destruction. For example, the holotype was found within 100 meters from a tourist camp. The intensified use agrochemicals has probably already destroyed much of its habitat, and unchecked littering poses further threats. It is therefore fortunate that protective measures and declaring its habitat a nature reserve are underway, as the area is rich in biodiversity.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 1 Feb 2023.
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