Northern dusky salamander

Description

Desmognathus fuscus is a species of amphibian in the family Plethodontidae (lungless salamanders). The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United States which form several distinct species, the southern dusky salamanders (D. auriculatus, D. valentinei). The northern dusky salamander is the most widespread representative of its genus in Canada. It can be found in eastern North America from extreme eastern Canada in New Brunswick south to South Carolina. The size of the species' total population is unknown, but is assumed to easily exceed 100,000. The species' habitat differs somewhat geographically; dusky salamanders in the northern part of the range prefer rocky woodland streams, seepages, and springs, while those in the south favor floodplains, sloughs, and muddy places along upland streams. They are most common where water is running or trickling. They hide under various objects, such as leaves or rocks, either in or near water. Alternatively, they may enter burrows for protection. The dusky salamander lays its eggs close to water under moss or rocks, in logs, or in stream-bank cavities. The larval stage which follows is normally aquatic. A small but sturdy salamander, the upper body of the northern dusky salamander varies in colour from reddish-brown to gray or olive, with a white or grey underside. The body is sparsely covered with dark spots or mottling concentrated on the sides. It also has a light dorsal stripe or two dark stripes that continue on to the first part of the tail. Juvenile colouring consists of five to eight pairs of dorsal spots or blotches located between the front and hind legs. Older individuals tend to be uniformly dark brown or black. As with all dusky salamander species, both juveniles and adults have a pale single stripe outlined in black that extends from the eye and runs diagonally to the rear of the jaw. Additionally, both have 14 costal grooves, larger hind limbs than forelimbs, and a keeled (knife-like) tail that is triangular in cross-section and compressed laterally at the base. The tail is less than half its body length and is normally lighter in colour in comparison to the body. Adults attain lengths of up to 14 cm, with the average length of adult males and females being 9.4 cm and 8.6 cm, respectively.