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Allegheny Mountain Dusky Salamander

Desmognathus ochrophaeus

Family: Plethodontidae

COSEWIC status:
  • Endangered (Carolinian population)
  • Threatened (Great Lakes / St. Lawrence population)
SARA status:
  • Endangered (Carolinian population)
  • Threatened (Great Lakes / St. Lawrence population)
IUCN status:
  • Least Concern

Description

The Allegheny Mountain Dusky Salamander is slender-bodied and can attain a total length of 11 cm. Individuals are grey to dark brown with varying amounts of dark or light flecking. Most individuals have a red to yellow stripe that runs down the back and onto the tail, sometimes with dark chevron patterning down the centre. The dorsal stripe may not be apparent on some older individuals, which tend to be uniformly dark brown or black. The belly is light grey to brown and becomes darker with age. There is often an irregular dark line on each side that borders the dorsal stripe. This species has a distinctive light strip that runs diagonally from the eye to the back of the jaw. The tail is round in cross-section, the hind legs are larger than the front legs and individuals have 13–15 costal groves. Larvae are aquatic and have gills, a tail fin and straight dorsolateral stripes. 

Similar Species

The Allegheny Mountain Dusky Salamander is most easily confused with the Northern Dusky Salamander. The Northern Dusky Salamander has a tail that is laterally compressed, keeled (narrows to create an edge along the top) and has a triangular cross-section. The chevron-shaped patterning down the back is also characteristic of the Allegheny Mountain Dusky Salamander, though not all individuals have this patterning. Aside from the Northern Dusky Salamander, no other Plethodontid salamanders in eastern Canada have hind legs that are larger than the front legs or the distinctive light strip that runs from the eye to the back of the jaw. 

Distribution

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The Allegheny Mountain Dusky Salamander has an extremely restricted distribution in Canada and only occurs in two small, isolated locations; one on the Niagara Peninsula in Ontario and the other in southwestern Quebec. South of the border this species occurs in the Allegheny Mountains and surrounding area, from New York to eastern Tennessee.

Habitat

The Allegheny Mountain Dusky Salamander inhabits small, fast-flowing streams and seeps in forest habitats, as well as the stream banks and adjacent moist terrestrial habitats. Cover objects, such as rocks and woody debris are important microhabitats that provide moist conditions and shelter. Eggs are deposited under logs or rocks, in underground cavities or other moist environments along the margins of streams or seeps. Individuals hibernate underground in the stream bed or adjacent terrestrial habitat. 

Biology

Plethodontid salamanders, including the Allegheny Mountain Dusky Salamander, are also known as lungless salamanders because the adults do not have lungs or gills; instead, they absorb oxygen directly through their skin. They must remain moist at all times so that oxygen and carbon dioxide can diffuse through the skin. Allegheny Mountain Dusky Salamanders breed in the spring or the fall, and females lay between eight and 40 eggs in grapelike clusters, typically in the late spring or early summer. The female guards the eggs until they hatch about 45 to 60 days later. The larvae undergo metamorphosis within a few weeks to eight months, depending on whether or not they overwinter before transforming. Males reach sexual maturity at two or three years of age, while females mature at three or four years of age. Allegheny Mountain Dusky Salamanders may live up to fifteen years. Juveniles and adults primarily forage around the margins of streams and on the forest floor for insects, spiders, worms and other terrestrial invertebrates, while larvae primary eat aquatic benthic invertebrates. Individuals communicate with each other though body posture and scent marking, and they establish and aggressively defend territories. When threatened, individuals may autotomize (drop) their tail, which creates a diversion while the salamander escapes. Although the tail will grow back over time, the individual will have lost much of the fat reserves on which it relies to survive the winter.

Threats

The primary threat to this species is the loss of mature forest, primarily through urbanization, clearing of land for agriculture and logging. Pollution (e.g. herbicides, agricultural effluent and road salt) of the streams and seeps that this species inhabits can be detrimental since toxins are easily absorbed though their skin. Climate change and introduced pathogens pose potentially serious future threats to Canadian salamanders. 

Additional Information About This Species In Canada