It is known from thousands of articulated fossil skeletons, comprising various age classes and two different ecomorphs, discovered in diatomite deposits of the Truckee Formation near Hazen, Nevada.

It is thought that during the Miocene, the Sierra Nevada mountains may have been lower, allowing for some contiguous freshwater connections between the Pacific coast and the Great Basin, through which the ancestral stickleback population may have dispersed inland.

In addition, within Lake Truckee, G. doryssus evolved two different ecomorphs, which may potentially represent distinct species under a modern taxonomic classification, adapted to different habitats and feeding styles: a nearshore, benthic, predatory morph (Lineage II) with slightly more armor and an offshore limnetic, planktivorous morph with weak armor (Lineage I).

The sudden appearance of F. nevadensis and the dramatic drop in G. doryssus populations occurred on a rapid timescale comparable to that of modern biological invasions.

[1] Gasterosteus doryssus was originally described by David Starr Jordan within its own monotypic genus, Merriamella (named for Clinton Hart Merriam), which he mistook for an extinct silverside.