However, a 2017 study found all three to be phylogenetically distinct from one another and have deep divergence times dating back to the Late Miocene; E. spelaea is thought to be the sister species to the clade comprising E. nerea and E. braggi.

[3][6] The larvae of this salamander are bold in coloration: brownish or purplish gray, sometimes with yellow flecks on the sides.

Larvae that live in an environment with light, like outside the caves in brooks or streams, have fully functional eyes, even if their vision seems to fade in older individuals.

The Western grotto salamander has been described as an opportunistic and omnivorous feeder, which in addition to eating small aquatic animals is also coprophagic, feeding on bat guano, which is just as rich in nutrients as their living prey.

The adult form is pinkish white, sometimes with traces of orange on its tail, feet, and sides, and has 16–19 costal grooves.