Description
This cryptic species is very similar in coloration and external morphology to its two close phylogenetic and geographic relatives Hydromantes shastae and H. samweli. These three species share the general features of the genus in being of moderate size (maximum standard length of H. wintu is less than 70 mm) and having a short (less than 35 mm), strongly tapered, blunt-tipped tail. The head is broad and relatively flat. The limbs are relatively long and overlap by as much as one costal interspace when adpressed to the sides of the body. The trunk has a blocky appearance because of the elongate, muscle enwrapped epibranchials that lie under the skin of the back. The digits are relatively long and stout and are webbed at their base, leading to the vernacular name applied to the genus, web-toed salamanders. The relative finger lengths are 1 < 4 < 2 < 3 and the relative toe lengths are 1 < 2 < 5 < 4 < 3 (Bingham et al. 2018).

The species differ in measurements analyzed used in a multivariate morphometrics analysis but otherwise the three species are separated by allozymic and DNA sequence differences. This species differs from H. shastae in having a shorter digit 3 on the foot. The maxillary teeth of the males are elongate and oriented on the bone so as to protrude from the side of the mouth (Bingham et al. 2018).

In life, these salamanders have a generally gray to gray-brown coloration with yellowish or reddish highlights, and the gray color has a metallic sheen. The lower surfaces are a flat gray color. The iris is a bright, metallic, pale yellow on the upper region. In preservative, the specimens are various shades of cinnamon (Bingham et al. 2018).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: United States

U.S. state distribution from AmphibiaWeb's database: California

View distribution map in BerkeleyMapper.

The species is endemic to limestone dominated local habitats in a geographically restricted area of no more than 5 km² along and between Marble Creek and Potter Creek at the end of the Shasta Reservoir peninsula lying between the McCloud river arm and the main Pit River arm of the reservoir, on the McCloud side, Shasta County, northern California. The vegetation in the region is a mosaic of hardwood, conifer, and hardwood-conifer forest with chaparral inclusions. Winters are cool and wet, and surface activity occurs during this time; salamanders can be found under rocks and other surface cover. Summers are long periods (5 to 7 months) of hot, very dry weather, and underground retreats are essential. Caves and limestone fissures are used, especially during the summer. The species is distributed discontinuously, in generally small patches of habitat (Bingham et al. 2018).

To illustrate the distributions of the H. shastae group, the map shows Hydromantes shastae in green, H. samweli in orange, and H. wintu in pink (after Bingham et al 2018); the previous range map for H. shastae is outlined in black.

Life History, Abundance, Activity, and Special Behaviors

Members of the shastae species complex are excellent climbers and use their webbed toes to climb on sheer, slippery rock surfaces (Gorman and Camp 1953).

Eggs have been found in moist caves during the summer (Gorman 1956).

The species is locally common on the surface during moist periods in fall, winter and spring seasons.

Trends and Threats
The construction of Shasta Dam mid-20th century likely submerged low-lying populations of this species. Plans to raise the level of the dam may pose a threat for some populations; most populations occur at elevations far above lake level and should be safe. Current lake level is 328 m and populations are known to occur as high as 527 m.

At present this species is safely away from humans in a road-less and trail-less area and can be reached only by boat.

Comments
This species has a very small geographic range and is only known from an isolated portion of the main range of the Shasta Salamander complex. Yet, it is the most distinctive in terms of molecular data and is as closely related phylogenetically to the Hydromantes platycephalus complex in the Sierra Nevada, well to the east and south, as to geographically closer species (Bingham et al. 2018).

The species epithet, “wintu” is in honor of the Winnemem Wintu Tribe, the original inhabitants of where the species is found (Bingham et al. 2018).

References

Bingham, R. E., Papenfuss, T. J., Lindstrand III, L., Wake, D. B. (2018). ''Phylogeography and species boundaries in the Hydromantes shastae complex, with description of two new species (Amphibia: Caudata: Plethodontidae).'' Bulletin of the Museum of Comparative Zoology, 161(10), 403-427.

Gorman, J. (1956). ''Reproduction in plethodontid salamanders of the genus Hydromantes.'' Herpetologica, 12, 249-259.

Gorman, J. and Camp, C. L. (1953). ''A new cave species of salamander of the genus Hydromantes from California, with notes on habits and habitats.'' Copeia, 1953, 39-43.

Species Account Citation: AmphibiaWeb 2021 Hydromantes wintu: Wintu Shasta Salamander <https://amphibiaweb.org/species/8812> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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