[4][3] It is considered a medium-sized example of the family, with an average snout–vent length of 76 to 77 mm,[5][6] with males usually larger than females.

[8] The specific name sarmientoi comes from the Spanish explorer Pedro Sarmiento de Gamboa, known for his early transit through the Strait of Magellan, which runs near the habitat of the species' population.

[9] L. sarmientoi is considered one of the southernmost lizard species in the world,[6][10][11] being endemic to the extreme southern regions of Chile and Argentina, known as Patagonia.

[3][5][10] The species is saxicolous, or an inhabitant of rocky, volcanic habitats, found along the arid, windswept steppe.

[3] The reproductive cycle of the species is annual and takes place during the spring and summer, however, depending on climatic conditions, females of the species can adjust the reproductive cycle based on energy and food restrictions.