The snakes were already described between 1872 and 1911.
The Persian dwarf snake (Eirenis persicus), long thought to be a single species, is actually six distinct snakes, according to a paper published in the Zoological Journal of the Linnean Society. The six species are Eirenis nigrofasciatus, Eirenis walteri, Eirenis angusticeps, Eirenis walteri, Eirenis mcmahoni and Eirenis occidentalis.
Researchers from six countries examined 30 male and 30 female specimens from the field and in museums using geometric morphometrics, molecular phylogeny and ecological niche modeling to notice the distinctions and conducted molecular clock analysis to determine that the E. persicus species group diverged between the “Eocene to Pliocene orogeny events subsequent to the Arabia–Eurasia collision.”
The snakes were already described between 1872 and 1911, but during the last half of the 20th century, they were considered a single species with varying colorations because the morphology between the six snakes were very similar.
The snakes can be found in an area that covers southern Turkey to the northeast of Pakistan.