The species is endemic to Sombrero, a small, uninhabited island in the Lesser Antilles under the jurisdiction of Anguilla.

It is superficially similar in coloration and scalation to P. atratus and P. corax, two other melanistic species also found on small, barren islands in the Caribbean.

[1] Although there are no permanent human settlements on Sombrero, increased rodent populations such as introduced mice may put pressure on the lizards.

[1] The population appeared to be thriving in the early 2000s, possibly due to its isolation from human activity[5], then crashed steeply to less than 100 individuals as of 2018 due to a combination of invasive species (primarily mice), severe hurricanes, and general environmental degradation.

Mouse eradication and native plant restoration by conservation groups allowed the population to rebound to more than 1,600 individuals as of 2024.