Coeur d’Alene salamander

Coeur d'Alene Salamander

The Coeur d'Alene salamander, scientifically designated as Plethodon idahoensis, is a species of woodland salamander belonging to the family Plethodontidae, commonly known as lungless salamanders. Its natural range is confined to the northern regions of Idaho, western Montana, and the southeastern part of British Columbia. The species was first identified in 1939 by James R. Slater and John W. Slipp, who discovered it near the south shore of Lake Coeur d'Alene in northern Idaho. Although it was once classified as a subspecies of Van Dyke's salamander, current understanding recognizes it as a distinct species.

Description and Distribution

Adult Coeur d'Alene salamanders are characterized by their slender form, typically measuring between 2 to 4 inches in length. Distinctive markings include a dark base coloration overlaid with a prominent yellow-gold dorsal stripe that runs along the entire length of the body, complemented by yellow patches on the throat. A key feature for identification is the presence of a nasolabial groove, parotoid glands, and parasphenoid teeth. The toes of this species are notably shorter than those of the long-toed salamander, aiding in differentiation. The eggs are also unique, appearing unpigmented and clustered like grapes, each attached by a single thread.

The majority of the Coeur d'Alene salamander population is concentrated in northern Idaho, with documented occurrences in western Montana and southeastern British Columbia. While approximately 95% of observed populations in Idaho and Montana have been confirmed as extant since 1987, the status of the remaining populations is less certain due to a general lack of detailed population trend data. The species is most frequently observed in the St. Joe and North Fork Clearwater River basins, but also extends into the Selway, Kootenai, and Moyie drainages.

Habitat and Lifestyle

The preferred habitat for the Coeur d'Alene salamander consists of moist environments with fractured rock formations, particularly within stream riparian zones, the splash zones of waterfalls, and in proximity to seeps and springs. They are often found in stream-side scree areas, consistently associated with fresh, moving water.

These salamanders are primarily nocturnal, emerging from concealment only when the ambient temperature exceeds 45°F. Their activity patterns are influenced by environmental conditions; surface activity is reduced during high daytime temperatures and prolonged dry periods. In northern Idaho, they emerge from hibernation in late March and remain active near the surface through April and May. From June through mid-September, they retreat underground to aestivate, seeking refuge from warmer conditions. A secondary period of activity commences with the arrival of rains in September through early November, after which they enter another hibernation phase until the following spring. Their diet comprises aquatic insects and other invertebrates that are also active during these nocturnal periods.

Reproduction and Conservation

Reproduction involves clutches of eggs that vary in size, typically ranging from approximately four to 13 eggs. The eggs themselves are unpigmented and are found in grape-like clusters, each secured by a single thread.

Due to a scarcity of research and infrequent sightings, comprehensive population trend data for the Coeur d'Alene salamander is limited. While small sites are believed to host abundant populations, the absence of systematic monitoring programs means that little data is available to assess population trends accurately. This lack of information has resulted in the Coeur d'Alene salamander being listed on both Idaho and Montana's Species of Special Concern lists, underscoring the need for increased conservation efforts and research.