Northern Dusky Salamander

Northern dusky salamander John White

Northern Dusky Salamander
(Desmognathus fuscus)

Other names: Salamandra fusca, Desmognathus phoca

Status:

 

Characteristics

The northern dusky salamander is tan to dark brown in colour with sparse dark spots or mottling that is concentrated on the sides, and may also have a light dorsal stripe or two dark dorsal stripes. Old individuals are generally uniformly dark with white spots on the sides. Juveniles have five to eight pairs of spots on the back between the front and hind legs. The underside is lighter in colour with white or grey spots. As in all dusky salamander species, a pale line runs diagonally from the eye to the jaw, and the hind legs are larger than the front legs. This species is also heavier bodied than other lungless salamanders, such as the eastern red-backed salamander, and has a sharply keeled tail that is triangular in cross-section and laterally compressed at the base. Adults attain lengths of up to 14 centimetres.

Similar Species

The northern dusky salamander can be easily confused with the Allegheny mountain dusky salamander, which often has chevron-shaped dorsal spots. The tail of the Allegheny mountain dusky salamander is rounded at the base rather than laterally compressed. The northern dusky salamander can be differentiated from all other lungless salamanders in Ontario (eastern red-backed, two-lined and four-toed) by the line running from the eye to the back of the jaw, the heavier body and hind legs that are larger than the front legs.

Habitat

The northern dusky salamander inhabits mountain springs, seepages and small headwater streams in forested areas. Although it actively forages on the forest floor, this species is rarely found far from its aquatic habitat. Subterranean retreats and cover objects such as rocks, logs, moss and leaf litter are important microhabitats that this salamander uses for foraging, nesting and avoiding desiccation and predators. It overwinters in underground retreats or in streams, where it may remain active throughout the winter.

 

Biology

Northern dusky salamanders belong to the “lungless” salamander family; they do not have lungs but breathe directly through their skin, which must remain moist to facilitate breathing. They breed on land in the spring or fall and have elaborate courtship rituals. The female deposits 10 to 30 eggs under logs, moss or rocks along stream edges in areas where the soil is saturated with water, and remains with the eggs to protect them from predation and desiccation until they hatch six to 10 weeks later. The aquatic larvae, which are about 1.5 centimetres long when they hatch, metamorphose into semi-terrestrial adults after about one year. They reach sexual maturity at 3 to 4 years of age when they have reached a snout-to-vent length of about four centimetres, and may live up to 15 years. Northern dusky salamanders forage primarily at night to avoid desiccation, and eat a variety of aquatic and terrestrial invertebrates.

Threats & Trends

The northern dusky salamander relies on clean headwater streams. Pollution from urban, agricultural or industrial areas is a significant threat to this species. Changes to the groundwater table or stream flow can have significant negative impacts on salamander populations by causing the loss of aquatic habitat, bank instability from excess runoff, or changes to the moisture regimes of terrestrial habitats. Forestry activities can also degrade aquatic habitat by causing siltation of streams, as well as alter the microhabitat conditions of the forest floor. The Ontario population of the northern dusky salamander is especially susceptible to extirpation due to changes in water quality or quantity, since the population relies on a single watershed. This species is rare in Ontario, where it is at the northern limit of its range, and trends in the species’ population levels and distribution are unknown.

Current Status & Protection

The northern dusky salamander is currently listed as Endangered under the Ontario Endangered Species Act, 2007 and Not at Risk under the federal Species at Risk Act. The species has been designated as a Specially Protected Amphibian under the Ontario Fish and Wildlife Conservation Act. These acts offer protection to individuals and their habitat. The habitat of this species is further protected in Ontario by the Provincial Policy Statement under the Planning Act. The International Union for Conservation of Nature lists the global status of the northern dusky salamander as Least Concern. The species’ status was confirmed in May 2011. Additional detail about legal protection for species at risk in Ontario is available on our Legal Protection page.

Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Amphibian Stewardship page.

 

 

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Range

To view an interactive map of the known ranges of northern dusky salamanders in Ontario, click here.

The northern dusky salamander inhabits the mountainous regions of eastern North America from New Brunswick and southern Quebec south to South Carolina and west to eastern Tennessee and western Kentucky. This salamander is widespread in Quebec south of the St. Lawrence River and in southern New Brunswick, but only one population occurs in Ontario, in a few areas along the Niagara Gorge.

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