AmphibiaChina 中国两栖类.

Description
Measured from one adult female holotype, Echinotriton maxiquadratus has a snout-to-vent length of 85.72 mm, a total length of 129.47 mm, an axilla-groin length of 39.01 mm, a chest width of 16.69 mm, an average forelimb length of 26.32 mm, an average hindlimb length of 27.62 mm, a head length of 18.28mm, and a head width of 25.81 mm. The head is roughly triangular, flat, and wider than it is long. The head has distinct quadrate spines, seen as a trapezoid-shaped projection posterior to the mouth. Other head features include lateral cranial ridges, a median cranial ridge, a V-shaped ridge connected to the vertebral ridge, and flattened parotoid glands. The gular fold is distinct. 12 glandular warts extend laterally in a row out from the body. The flattened vertebral ridge on the dorsal surface is widest at the middle of the body and tapers towards the head and tail. Limbs are slender and digits are compressed with rounded tips. The relative lengths of the four fingers are 3 > 2 > 1 > 4 and the relative lengths of the five toes are 3 > 4 > 2 > 1 > 5. Toes have rudimentary interdigital webbing. The tail is laterally compressed, thicker on the ventral side than the dorsal side, and has a sharp dorsal fin as a continuation of the vertebral ridge. The skin is densely covered with glandular tubercles across the dorsal surface, ventral surface, and flanks (Hou et al. 2014)

Echinotriton maxiquadratus is generally distinguished from closely related species by a trapezoid-shaped projection posterior to the mouth representing the quadrate spines. In other species of Echinotriton, the projection is triangular. Echinotriton maxiquadratus can be further distinguished from E. andersoni by having only single lines of warts on either side of the body and a normal 5th toe rather than 1-3 rows found and rudimentary toe in E. andersoni, and from E. chinhaiensis by having its longest finger extend past the rostrum when the limb is extended toward the head and by having conical skin tubercles (Hou et al. 2014).

Echinotriton maxiquadratus is primarily black in life with some orange and yellow features. Its 2nd and 7th lateral warts are a mix of gray and yellow. The tip of the quadrate projection, digits, carpal and tarsal tubercles, cloaca, and ventral ridge of the tail are yellow-orange (Hou et al. 2014).

Only one holotype of the species has been discovered (Hou et al. 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

View distribution map in BerkeleyMapper.

Echinotriton maxiquadratus lives in the mountains of Southern China. Exact coordinates and elevation data are held at the Shenyang Normal University and are not released to the public for conservation purposes. The montane environment is humid and receives frequent rainfall (Hou et al. 2014).

Life History, Abundance, Activity, and Special Behaviors
Echinotriton maxiquadratus is mostly terrestrial, found under cover such as rocks. It inhabits low depressions near the mountain-top characterized by lentic lakes and marshland surrounded by tall grasses, rhododendrons, and melastomes. The species is rare (Hou et al. 2014).

Trends and Threats
Echinotriton maxiquadratus likely has a very small population size. Its recommended status is Critically Endangered. It is threatened by habitat loss due to agriculture and tourism and its location has not been made public due to concerns of extinction through illegal collection (Hou et al. 2014).

Relation to Humans
There are no reported direct interactions between E. maxiquadratus and humans.

Possible reasons for amphibian decline

General habitat alteration and loss
Intensified agriculture or grazing

Comments
The species authority is: 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 description of a new species from southern China.” Zootaxa, 3895(1), 89-102.

Echinotriton maxiquadratus is a new species within the genus Echinotriton, the sister taxon to Tylototriton. Echinotriton and Tylototriton are known as the “primitive newts” within the family Salamandridae. Nuclear and mitochondrial data conflict over the specific placement of E. maxiquadratus within the genus Echinotriton (Hou et al. 2014).

The species epithet, maxiquadratus combines maximus, or “greatest,” and quadrate. The quadrate bone has large spines in this species (Hou et al. 2014).

Echinotriton maxiquadratus fills a gap in the geographic distribution of the genus Echinotriton. The other two species in the genus, E andersoni and E. chinhaiensis, are found in Japan and eastern Zhejian province in China, respectively. It has been hypothesized that a land bridge used to connect the Japanese archipelago, Taiwan, and China. The locality of E. maxiquadratus in Southern China fits between the disjunct distributions of E andersoni and E. chinhaiensis, supporting a dispersal route for Echinotriton from China up into the Japanese archipelago (Hou et al. 2014).

References

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 description of a new species from southern China.'' Zootaxa, 3895(1), 89-102.

Species Account Citation: AmphibiaWeb 2015 Echinotriton maxiquadratus: Mountain Spiny Crocodile Newt; Gao Shan Ji Yuan (Chinese) <https://amphibiaweb.org/species/8273> University of California, Berkeley, CA, USA. Accessed Dec 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Dec 2024.

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