This is a relatively robust, moderately large species, with males reaching 65 mm snout-vent length and females nearly 70 mm (about 110 mm total length). It is the largest of the American Hydromantes. The body is somewhat flattened and rectangular in cross-section, and the broad, flattened head has large, protuberant eyes. The limbs are long and bear large, relatively webbed hands (with 4 digits) and feet (with 5 digits). There are 13 costal grooves. The tail is much shorter than the head plus body and is relatively blunt-tipped. This is the most uniformly colored member of its genus. The basic color is a rich dark brown, occasionally with some obscure darker patches. Ventrally the animal is a paler gray color.
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The video below shows Hydromantes brunus using its tail as a fifth leg.
This is a local endemic, known only from a small region in the foothills of the Sierra Nevada in Mariposa County, California, along a short section (about 16-17 km) of the Merced River, from the vicinity of the type locality at Briceburg,west to Hell Hollow, and a short distance up the North Fork of the Merced River, between elevations of 365-760 m. The vegetation in the region where salamanders are found is mainly chapparal, with a scattering of xeric-adapted trees such as gray pine (Pinus sabinianus), and with California laurel (Umbellularia californica) in more mesic sites.
Egg depostion has not been observed, nor has development, but its close relatives undergo direct development. Ovarian eggs were enlarged (4.6 mm in diameter) in the holotype, collected in late February (Gorman, 1954). Eggs are probably laid in late spring and develop over the summer.There is a general association with limestone, but salamanders have been found on the surface both under slate slabs and irregularly shaped pieces of limestone. They have been found in small areas of moss-covered talus.
The most significant threats to the species appear to be from the construction of dams, which has caused some local flooding, and road-building.
The Limestone salamander is a highly localized endemic of the Sierra Nevada forests foothills conifned to a limited reach of the Merced River. The Sierra Nevada forests are the forested areas of the Sierra Nevada Mountains, which run northwest to southwest and are approximately 650 kilometers long and 80 km wide. The range achieves its greatest height towards the south, with a number of peaks reaching heights of over 4000 meters. Several large river valleys dissect the western slope with dramatic canyons. The eastern escarpment is much steeper than the western slope, in general.
The Sierra Nevada forests ecoregion harbors one of the most diverse temperate conifer forests on Earth displaying an extraordinary range of habitat types and supporting many unusual species. Fifty percent of California's estimated 7000 species of vascular plants occur in the Sierra Nevada, with 400 Sierra endemics and 200 rare species. The southern section has the highest concentration of species and rare and endemic species, but pockets of rare plants occur throughout the range.
Sierra Nevada amphibian endemics are the Yosemite toad, Mount Lyell salamander (Hydromantes platycephalus), the Vulnerable Limestone salamander (Hydromantes brunus), Kern salamander and the Endangered Inyo Mountains salamander (Batrachoseps campi). The non endemic amphibians are: the Endangered Southern mountain yellow-legged frog (Rana muscosa); the Near Threatened Cascades frog (Rana cascadae); Northern red-legged frog (Rana aurora); Pacific chorus frog (Pseudacris regilia); Foothill Yellow-legged frog (Rana boylii); Long-toed salamander (Ambystoma macrodactylum); and the Monterey ensatina (Ensatina eschscholtzii).
A considerable number of mammalian taxa are found in the ecoregion, including the Long-eared chipmunk, Alpine chipmunk, Western heather vole, Walker Pass pocket mouse, and the Yellow-eared pocket-mouse. A diverse vertebrate predator assemblage once occurred in the ecoregion including Grizzly bear (Ursus arctos), Black bear (Ursus americanus), Coyote (Canis latrans), Mountain lion (Puma concolor), Ringtail (Bassariscus astutus), Fisher (Martes pennanti), Pine marten (Martes americana) and Wolverine (Gulo gulo).
There are a small number of reptilian taxa present in the Sierra Nevada forests: sagebrush lizard (Sceloporus graciosus); Northern alligator lizard (Elgaria coerulea); Southern alligator lizard (Elgaria multicarinata); Sharp-tailed snake (Contia tenuis); California mountain kingsnake (Molothrus ater); Common garter snake (Thamnophis sirtalis); Couch's garter snake (Thamnophis couchii); Western gopher snake (Pituophis catenifer); Longnose snake (Rhinocheilus lecontei); and the Common kingsnake (Lampropeltis getula).
A number of bird species are found in the ecoreion including high level predators that include several large owls, hawks and eagles. Other representative avifauna species present are the Blue-headed vireo (Vireo solitarius); Brown-headed cowbird (Molothrus ater); and the Near Threatened Cassin's finch (Carpodacus cassinii).
The limestone salamander (Hydromantes brunus) is a member of the lungless salamander family. Discovered in 1952, this species belongs to the only genus of salamanders found both in New and Old World.[2] It is endemic to a portion of the Merced River Canyon in Mariposa County, California.
The limestone salamander has a flattened body, head, webbed toes, and a short tail. It is typically 5.0-7.5 cm in length. Adults are brownish with a pale ventral surface; the male has oval-shaped mental gland. The species was originally thought to be life-birthing,[3] but is now known to lay eggs. Young hatch in the egg and emerge fully formed, with no larval stage. They are yellowish greenish, darkening with age.[4] Like all lungless salamanders, it respires through its skin.
The genus Hydromantes is endemic to California.[4] The limestone salamander occurs only in the Lower Merced River drainage, in several disparate localities, at elevations of 300–760 m in inhabits canyon slopes that are greater than 35 degrees.[1][5] Habitats include moss-covered limestones outcroppings, chaparral, under rocks and logs in moist environments. During dry weather it stays underground in caves and rock crevices.[1]
The limestone salamander is classified as Vulnerable by the IUCN, mostly because it is known from fewer than five locations (where the species appears to be uncommon but not rare). Under the Department of the Interior, US Fish and Wildlife, its Federal listing status is currently under review. The species is listed as Threatened by the California Department of Fish and Wildlife under the State Endangered Species Act. A proposed gold operation mine in Hell Hollow is thought to be the most immediate threat, in addition to general habitat loss due to construction of highways, quarries and dams.[1] A portion of the Merced River Canyon is protected by the State of California and managed by the State Department of Fish and Wildlife as the Limestone Salamander Ecological Reserve (~120 acres); a further 1,600 acres have been designated as the Limestone Salamander Area of Critical Environmental Concern.[1][5]
The limestone salamander (Hydromantes brunus) is a member of the lungless salamander family. Discovered in 1952, this species belongs to the only genus of salamanders found both in New and Old World. It is endemic to a portion of the Merced River Canyon in Mariposa County, California.
