Larch Mountain salamander (Plethodon larselli)

Physical description

The Larch Mountain salamander is a small, lungless, striped salamander (less than 2 inches snout to vent length) and 4.33 inches total length. The color on the sides is black or dark brown with white speckling and there may be flecks of the dorsal (topside) stripe color. The dorsal stripe is reddish, yellowish, brown, or tan, and has a scalloped edge and extends to the tip of the tail. The underside is characteristically salmon-pink, red, or reddish orange but a small number of individuals have white or gray undersides. In some adults, with age, the stripe becomes obscured by the large amount of dark pigmentation.

The outer toe on the hind foot has only one segment (phalanx). The costal groove count ranges between 14 and 16 but is usually 15.

The presence of the nasolabial grooves (nose to mouth indentations) separates Lungless Salamanders from other types of salamanders.

The Woodland Salamanders (Plethodon species) in Washington are similar in general appearance. The following traits distinguish the Larch Mountain salamander: 1) the underside is pinkish or red, 2) the dorsal stripe has a scalloped edge with dark pigmentation in a herringbone configuration, 3) there is dense white flecking on the intercostal folds but not in the costal grooves, 4) the stripe typically ends at the base of the head and, 5) the outer toe on the hind foot is a quarter the size of the fourth toe.

The traits listed above for adults are often lacking, subtle or difficult to see in small juvenile Larch Mountain salamanders and they can be easily confused with western red-backed salamanders. However, juvenile Larch Mountain salamanders usually have some reddish pigment blotches or flecks on the belly.

There is no free-living larval stage of Larch Mountain salamander; hatchlings emerge as fully formed miniature versions of the adults. Coloration in juveniles is similar to adults, but the dorsal stripe is more even-edged with brighter coloration and the red pigmentation on the belly tends to be limited to single or multiple blotches or flecks.

For more details about Larch Mountain salamander, see the Washington Herp Atlas.

Ecology and life history

Larch Mountain salamanders are associated with talus, scree, gravelly soils and other areas of accumulated rock where spaces exist between the rock and soil. This species inhabits a diverse range of forested and non-forested habitats.

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Photo by William Leonard

Occupied rocky substrates in non-forested areas are usually north facing, and nonvascular plants, especially mosses, dominate the ground cover. In some areas of the Cascade Mountains, Larch Mountain salamanders inhabit old-growth coniferous forests without significant exposed rocky areas. They also inhabit lava tubes in the Mount St. Helens vicinity.

Important microhabitats include woody debris, leaf litter, and/or rocks.

Larch Mountain salamanders are lungless and depend on their moist skin surfaces for oxygen uptake. They spend most of their lives in the subterranean environment, only being surface-active about 20 to 90 days per year. Surface activity is triggered whenever moisture and temperature regimes are appropriate, primarily in the spring and fall.

Breeding takes place in the autumn and spring months. No nests have been found. Development of larvae takes place in the egg, and there is no free-living aquatic larval stage.

Sexual maturity is reached at 3 to 3.5 years for males and 4 to 4.5 years for  females. Larch Mountain salamanders are predators on a variety of invertebrates.

The movements are poorly documented, but home ranges tend to be only 10 to 100 feet in diameter. 

Geographic range

The Larch Mountain salamander is native to Washington and northern Oregon. The main distribution is along a 34-mile stretch of the Columbia River Gorge in southern Washington and northern Oregon, and discontinuously northward in the Cascades in the Snoqualmie Pass-Kachess Lake area.

This map from the Washington Herp Atlas illustrates the distribution of Larch Mountain salamander in Washington based on records in the WDFW database as of 2016. If you see this species in areas that are not indicated on the map or have more recent observations (less than 10 years), please share your observation using the WDFW wildlife reporting form. 

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For maps of range-wide distribution and conservation status of this species, check out NatureServe Explorer and the International Union for the Conservation of Nature Red List.