Cœur d’Alene salamander COSEWIC assessment and status report: chapter 3

Species Information

Name and classification 

The Coeur d'Alene Salamander, Plethodon idahoensis, (figure 1) is a member of the family Plethodontidae (lungless salamanders). First described as a species by Slater and Slipp (1940), it was subsequently considered to be a subspecies of Van Dyke’s Salamandaer, i.e. Plethodon vandykei idahoensis, by Lowe 1950. Collins (1990) recommended that this taxon be recognized as a distinct species. The distinction of P. idahoensis at the species level has since been corroborated by morphometric analysis (Wilson and Larsen 1998) and genetic work (Howard et al. 1993; Carstens et al. 2004, 2005).

Figure 1. Adult Plethodon idahoensis

Figure 1. Adult Plethodon idahoensis

Morphological description

Body color is dark brown to black, with light flecking on the sides and legs. In Canada, dorsal stripe coloration is primarily pale orange, yellow or occasionally red. The stripe does not extend to the tip of the tail, has irregular edges, and may be interrupted. A yellow throat patch is usually present on the underside of the head. Juveniles are similar to adults in appearance.

The trunk generally has 14 costal grooves. The legs are typically long, with 0.5 - 3 costal folds present between adpressed limbs (Wilson and Ohanjanian 2002). The slightly webbed toes are short. Plethodon idahoensis has parotoid glands at the back corners of the head and males have a mental gland. Females are larger than males (Nussbaum et al. 1983), with a maximum snout-to-vent length (SVL) of 69 mm recorded from a female north of Creston, B.C. (Ohanjanian and Beaucher 2002). Among adult P. idahoensis captured between 2000 and 2003 at 13 sites in southeastern British Columbia, mean snout-to-vent length (SVL) was 54.0 mm + 4.8 (SD) (n = 248, range 45-69 mm). Mean total length (TL) was 109 mm + 10.5 (n = 248, range 79-132 mm) (Ohanjanian, unpubl. data). In juveniles from the same sample, average SVL was 34.3 mm + 7.4 (SD) (n = 143, range 19 to 44 mm) and average TL was 67.0 mm + 16.4 (n = 143, range = 34 – 100).

Genetic description

Plethodon idahoensis shows significant genetic distinctiveness from P. vandykei (Carstens et al. 2004, 2005). Divergence resulting from vicariance (or geographical barrier(s) restricting gene flow) and isolation has been long-term.

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