The Mountain Dusky Salamander, Desmognathus ochrophaeus, can be found in the forested foothills and peaks of the Adirondack and Applachian Mountains of the United States. There is a small population in extreme southeastern Quebec, Canada, in the foothills of the Adirondacks, and a few isolated populations in northeast Kentucky and west-central Georgia (Conant and Collins 1998).
Adult Desmognathus ochrophaeus tend to be relatively stationary and stays within a 1 meter radius in the temperate forest biome. This biome consists of deciduous trees and widely varying temperatures (-30 degrees Celsius in the winter to +30 degrees Celsius in the summer.) Precipitation in this biome is relatively high and evenly distributed throughout the year. If you were to look for Desmognathus ochrophaeus, you would most likely find it near wet rock faces, springs, woodlands, seepage areas and streams, and under stones, logs and leaves where the ground is wet (Amphibians of Canada 2000).
Size: 7-10 cm
Desmognathus ochrophaeus have moderately long, well-developed legs and come in a variety of colors, markings, and body proportions. The salamanders of this species have long slender bodies and tapered tails. The eyelids fit under a fold of skin behind the eyes. The teeth are pointed and sharp. Most adults are plainly colored but others are brightly colored. In many, a light line extends from the eye to the bottom of the jaw. Both adults and juveniles have a straight light-colored stripe down the back and tail. This stripe can be yellow, orange, olive, gray, brown or red, and is flanked by darker pigmentation that is mottled and fade into the lightly pigmented belly. The dorsal stripe is sometimes marked by rows of dark chevron-like spots. As adults age, the central spots become darker, making these chevrons harder to notice. The sides of the tail are black and there is a lighter grayish brown dorsal band on their bodies.
In general, the males and females of this species resemble one another. However males are 12% larger than females, have a darker body and a more curved jaw margin than females. Females have vomerine teeth, whereas males lose them when they reach about 65-75 mm in length.
Juvenile Desmognathus ochrophaeus are dorsally spotted. They have a yellow dorsal band bordered by a dark brown stripe that stretches over the tail. The top of their heads are dark and their bellies are light.
The larvae of these salamanders are about 17 mm long. They have a light stripe extending from their eyes to their tail, flanked by a darker line of pigmentation. Upon hatching they are equipped with short white gills that are retained for a short while. (Bishop 1943; Amphibians of Canada 2000; The Virginia Fish and Wildlife Information Service 2001).
Salamanders of this species breed during spring and fall. Usually, during the months of April, September, and October, courtship and spermatophore deposition take place. Fertilization for Desmognathus ochrophaeus is internal. The male deposits sperm packets (spermatophores) on the ground, which the female takes into her vent. The female will store the sperm from fall and spring inseminations until late spring or summer. The sperm can be stored within her body from 1-2 years. After a certain period the ova are fertilized and gestate for about 3 months, before she lays her eggs. The female will then lay 3-27 eggs either singly, in pairs, or in clusters in a small cavity, which she hollows out in soil under moss, or in moss above shallow running water. A female will remain in her nesting cavity for a period from 52-69 days, attending her eggs with antipredator and antipathogenic behaviors. During this time she will rarely forage for food. Interestingly, Desmognathus ochrophaeus females will accept eggs belonging to another female and will attend to the new clutch and take care of it as if it were her own. Thus, in a sense, she becomes a foster parent! Scent is reported to be important in recognition of a clutch. Disturbed females may eat their eggs. Also, the presence of dead eggs in a clutch may trigger a female to eat her eggs.
The larvae hatch about 3 months after being deposited. Eggs hatch in both late summer from clutches brooded during summer, and early spring from clutches brooded during the winter. Hatchling larvae have gills, and quickly disperse to nearby water. Until they do, their mother continues to protect her brood. Most D. ochrophaeus larvae have metamorphosed into the adult form after a few weeks, but a few go more quickly (probably nourished by especially large and rich yolk in their egg) or take much longer, up to 8 months (Bishop 1943; Hairston 1987, Virginia Fish and Wildlife Information Service 2002).
Like many salamanders Desmognathus ochrophaeus mates by way of internal fertilization. The female of the species will release a scent from one of her "courtship glands" on a leaf, branch, bark, etc. that will coax a male to come and release a spermatophore on the ground. Desmognathus ochrophaeus are non-vocal and so must use scent cues to mate with each other. One very important sense involved in mating is olfaction. Using scents the female is able to entice the male to release his sperm package onto the ground, which she will then pick up and place directly into her vent. This differs from what we traditionally consider mating, because the male and female Desmognathus ochrophaeus do not physically make contact and induce a direct transfer of sperm to ova. Year after year an individual salamander will breed along the same segments of a stream.
These salamanders are most active at night and on dark, humid days. Adults may congregate in crevices and shale banks during winter.
An interesting behavior attributed to Desmognathus ochrophaeus that is common to many salamanders is the ability to lose their tail when threatened by a predator. On Desmognathus ochrophaeus and many other salamanders there is a predetermined zone of breakage at the base of the tail where it will break off, leaving the tail behind, but allowing the rest of the salamander to get away. When the tail breaks, segmental muscles pull out, leaving the tail behind. The contraction of sphincter muscles on the blood vessels minimizes bleeding. The broken tail will wiggle, contort, and move around to distract the predator, hopefully giving the salamander enough time to escape. The slamander may be short its tail, but at least he'll live for another day. Luckily for Desmognathus ochrophaeus, the tail eventually regenerates (Cohen 1995).
The larvae and adults of this species of salamanders are carnivores. After hatching the aquatic larvae feed on small aquatic arthropods and their larvae, including spiders, flies, and mosquitoes. The adult salamanders feed on adult and immature terrestrial arthropods, terrestrial gastropods, aquatic insects and aquatic snails. Some of the animals eaten include: earthworms, spiders, dragonflies, beetles, mites, and millipedes. Desmognathus ochrophaeus climbs trees and shrubs while foraging, and uses its keen vision to ambush prey rather than actively hunting it down. This may reduce the risk of injury (Amphibians of Canada 2000).
Desmognathus ochrophaeus plays a useful role in research and science. Biologists use the amphibian's eggs to study embryonic growth. The salamander also gives scientists a glimpse into metamorphosis and life cycles involving complex morphological changes. This helps them study problems in genetics, developmental biology, and tissue transplantation. Another use for Desmognathus ochrophaeus' eggs is in the field of toxicology. Scientists have used its eggs to assess the biotic effects of many substances that are significant to environmental and human health. (Cohen 1995).
Desmognathus ochrophaeus is not listed as endangered by any of these organizations, but is considered vulnerable by COSEWIC (Committee on the Status of Endangered Life in Canada). This is due in large part to overlogging and industrial intrusion into their natural habitats in the deciduous forests. As trees are cut down in deciduous forests for farming and logging industries, the natural habitat of the salamander diminishes and with it goes the population. Logging removes leafy canopies, which increases ground and stream temperatures and lowers humidity levels. This effectively destroys the wet, shady salamander habitat. Another reason for their "vulnerable" status is a change in the water table, either through human activity or climatic variation. Water usage for residential developments, resorts, and industries decreases the amount of available water for Desmognathus ochrophaeus' habitat. Although listed as "vulnerable," nothing is being done to preserve this species. (Hairston 1987).
Forest-floor salamanders like this species can be very important to the ecology of the forests of eastern North America. Though individually small, they may occur in great numbers, and have important effects on the flows of nutrients and energy through the ecosystems they live in (Hairston 1987).
Christopher Tsang (author), University of California, Irvine, Rudi Berkelhamer (editor), University of California, Irvine.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
Bishop, S. 1943. Handbook of Salamanders. Ithaca, New York: Comstock Publishing Associates a division of Cornell University Press.
Canada's Digital Collections: Amphibians of Canada, 2000. "Mountain Dusky Salamander: Desmognathus ochrophaeus" (On-line). Accessed February 19, 2001 at http://collections.ic.gc.ca/amphibians/taxa/species/desmognathus_ochrophaeus.html.
Cohen, N., R. Stebbins. 1995. A Natural History of Amphibians. New Jersey: Princeton University Press.
Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians: Eastern and Central North America. Boston, Massachusetts, USA: Houghton Mifflin Company.
Dunn, E. 1926. The Salamanders of the Family Plethodontidae. Massachussetts: Fiftieth Anniversary Publications.
Hairston, N. 1987. Community Ecology and Salamander Guilds. Melbourne, Australia: Cambridge University Press.
The Virginia Fish and Wildlife Information Service, 2001. "Taxonomy for (020036) Salamander, Allegheny mountain dusky Desmognathus ochrophaeus" (On-line). Accessed February 19, 2001 at http://vafwis.org/BOVA/BOOKS/020036.HTM.