The original description includes, "On the basis of present knowledge this subspecies differs from C. s. scutulatus in having less subdivision of the scales of the crown, a lower number of ventrals, and a less vivid coloration.

Crotalus scutulatus salvini is found in mostly arid scrub habitat, as well as adjacent grassland and foothills, from the State of Hidalgo, south through Tlaxcala and Puebla, to southwestern Veracruz, Mexico.

Then about 1.8 MYA, the subpopulation now identified as C. scutulatus salvini diverged genetically from the animals on the Central Mexican Plateau.

[8] More recently, qualitative, meristic, and morphometric traits from 347 specimens of C. scutulatus were analyzed, producing the conclusion that the species "is phenotypically cohesive without discrete subgroups, and that morphology follows a continuous cline in primary color pattern and meristic traits across the major axis of its expansive distribution," suggesting that "multiple episodes of isolation and secondary contact among metapopulations during the Pleistocene were sufficient to produce distinctive genetic populations, which have since experienced gene flow to produce clinal variation in phenotypes without discrete or diagnosable distinctions among these original populations."

It was recommended that, for taxonomic purposes, Crotalus scutulatus "be retained as a single species, although it is possible that C. s. salvini, which is morphologically the most distinctive population, could represent a peripheral isolate in the initial stages of speciation.