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Northern Dusky Salamander
(Desmognathus fuscus)


IDENTIFICATION: Ranges in size between 6.4-11.5 cm. The record longest is recorded at 14.1 cm. The distinguishing mark on all Desmognathus species is a pale line, slanting from the eye to the posterior edge of the jaw. They are more husky than the red back or two-lined, and their hind legs are much larger than front legs. The general coloration is gray to brown, markings not much different from ground color.

    -D. fuscus has a keeled tail with a sharp edge on top, which is most noticeable ¾ of the way down the tail.
    -D. ochrophaeus (Mountain Dusky) is very difficult to distinguish from D. fuscus, but has a rounder tail than D. fuscus. D. ochrophaeus (particularly juveniles) may also have a broad light stripe (tan, olive, gray, orange, brown, or even reddish in color) down its back, and look a bit like a redback.
    -D. monticola (seal salamander) is not found in eastern PA, but it also has a keeled tail with a knife-edge on top. Adults are generally larger than D. fuscus and all ages may have heavy black or brown dorsal spots.
CONSERVATION BIOLOGY: The northern dusky is very sensitive to any changes to streams, such as siltation or pollution including high metal concentrations. Disturbances caused by urbanization greatly reduce or eliminate dusky populations.
BREEDING/LARVAE: The breeding season is varied due to the geographic diversity of the species, but in most populations breeding occurs in both fall and spring with females reproducing once a year. In courtship, males apply the snout, cheeks and mental gland to the snout of the female, who usually responds by picking up a spermatophore.
HABITAT: Abundant in many localities such as brooks, near springs. Most common along edges of small woodland streams where stones, chunks of wood, and debris provide ample shelter both for the salamander and their food.
PREDATORS: The northern dusky lack chemical defenses such as skin toxicity so they use such mechanisms as biting and fleeing. They can also autotomize their tails or remain immobile when uncovered. Predators include, but are not limited to, water snakes, garter snakes, raccoons, birds, skunks, and spring salamanders.
FOOD: In Pennsylvania populations the two major sources of food are Lepidopteran larvae (butterflies/moths) and larval and adult flies. The northern dusky also eats terrestrial and semiterrestrial invertebrates. These include insects, spiders, centipedes, and snails. There are also reports of cannibalism within this species.
RANGE: The northern dusky can be found from parts of Canada and Maine south to South Carolina and west to Indiana and Kentucky.

     

References:

  • Collins, Joeseph T. and Conant, Roger. A Field Guide to Reptiles and Amphibians: Eastern and Central North America. Houghton Mifflin Company: Boston New York, 1998.

  • Petranka, James W. Salamanders of the United States and Canada. Smithosian Institution Press: Washington, 1998.

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