[2][3] It was previously thought to be a population of the Shasta salamander (H. shastae) and is not physically distinguishable, but a 2018 phylogenetic study found it to be a genetically distinct species.

It is named after its type locality, Samwel Cave, which originates from Sa-Wal, the Wintu name for grizzly bear.

[4] It is found in a fairly small area around the north-central and northwest sides of Shasta Lake, but possibly extending 20 km further to the west.

[2][5] Its distribution was likely fragmented by the creation of the lake and the construction of the Shasta Dam.

Proposals to raise the water levels would likely flood more habitats and further threaten it.