An adult limestone salamander crawls down a limestone rock and underneath another one.
A tiny juvenile limestone salamander is discovered when a rock is turned over. It is allowed to crawl outside of the footprint of the rock before the rock is replaced.
Adults measure 2 - 3 inches long (5 - 7.5 cm) from snout to vent length.
A small stocky salamander with webbed toes, nasolabial grooves, a flattened head and body, and 13 costal grooves.
Toe tips of adpressed limbs overlap by 1.5 costal folds.
Color and Pattern
Adults are a brownish color above with a pale ventral surface.
Male / Female Differences
Males have an oval-shaped mental gland.
Juveniles are yellowish green above, darkening with age.
Life History and Behavior
A member of family Plethodontidae, the Plethodontid or Lungless Salamanders.
Plethodontid salamanders do not breathe through lungs. They conduct respiration through their skin and the tissues lining their mouth. This requires them to live in damp environments on land and to move about on the ground only during times of high humidity. (Plethodontid salamanders native to California do not inhabit streams or bodies of water but they are capable of surviving for a short time if they fall into water.)
Plethodontid salamanders are also distinguished by their naso-labial grooves, which are vertical slits between the nostrils and upper lip that are lined with glands associated with chemoreception.
All Plethodontid Salamanders native to California lay eggs in moist places on land.
The young develop in the egg and hatch directly into a tiny terrestrial salamander with the same body form as an adult.
(They do not hatch in the water and begin their lives as tiny swimming larvae breathing through gills like some other types of salamanders.)
Little is known about this species.
H. brunus is active during wet or rainy periods in fall, winter, and spring when temperatures are not exceedingly low, and inactive during extreme winter weather and during hot, dry periods in spring, summer, and fall.
They might also be active in summer well below the surface where there is sufficient moisture - an adult was found active in a mine tunnel in July.
Uses its tail and webbed feet to assist in climbing.
When threatened, this salamander has been observed coiling and rolling downhill to escape.
(You can watch a short video of a different species of salamander using this coiling, rolling and springing escape technique here.)
Diet and Feeding
Probably consumes a variety of small invertebrates.
Little is known about the breeding behavior of this species.
Reproduction is terrestrial.
Females lay eggs most likely in deep moist talus or crevices in late spring.
Young develop completely in the egg and hatch fully formed in the summer..
Summer is hot and dry in the range of the Limestone Salamander, so hatchlings probably remain underground until at least the following fall rains.
H.brunus inhabits mossy limestone crevices and talus in the Grey Pine, Oak, Buckeye, Chaparral belt of the lower Merced River Canyon, typically on steep slopes. Has also been found in abandoned mine tunnels.
Endemic to California. Found along the Merced River from Lake McClure to about 4 miles NE of Briceburg, Mariposa County. Also occurs along the Merced River tributaries including Bear Creek and its feeder creeks, south of Briceburg.
Notes on Taxonomy
Discovered in 1952, H. brunus has always been considered a distinct taxon.
H. brunus is one of five species of Hydromantes, all of which are endemic to California. The others are the three Shasta complex Hydromantes and H. platycephalus.
Eight species of similar salamanders once placed in the genus Hydromantes but now placed in the genus Speleomantes occur in Italy and southern France and on the island of Sardinia. They are the only plethodontid salamanders found outside of the Americas. (A new species of lungless salamander found in Asia in 2004 was placed in a new genus.) Why Hydromantes/Speleomantes are found only in Europe and California is still a biogeographical mystery.
SSAR Herpetological Circular No. 43, 2017 shows the following note:
"Rovito (2010, Mol. Ecol. 19: 4554–4571) evaluated genetic variation in both mitochondrial and nuclear genes in H. brunus and H. platycephalus and those data supported the hypothesis that H. brunus was derived from H. platycephalus by peripatric speciation. Thus H. platycephalus is paraphyletic, but no changes in its taxonomy were suggested."
This salamander is listed as a threatened species by the state, due to its limited range and habitat, although there is no indication that their range or population density have decreased or changed significantly. But there have not been any discoveries of new populations in many years, either.
Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.
Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.
Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.
Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.
Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.
Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.
Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.
Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.
Bishop, Sherman C. Handbook of Salamanders. Cornell University Press, 1943.
Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005.
Petranka, James W. Salamanders of the United States and Canada. Smithsonian Institution, 1998.
The following conservation status listings for this animal are taken from the October 2021 California "Special Animals List" and the October 2021 "State and Federally Listed Endangered and Threatened Animals of California" list, both of which are produced by multiple agencies and available here: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. You can check the link to see if there are more recent lists.
If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can go to the NatureServe and IUCN websites to check their rankings.