[1] Found in pantropical regions, it was formally described as a new species in 2013 by Dutch lichenologist André Aptroot.

The type specimen of P. inspersum was collected by the author in Kuranda, Queensland, along the Jumrum Creek track, growing on a twig.

[2] The thallus of P. inspersum is ecorticate and pinkish-grey, exhibiting no fluorescence under ultraviolet light (UV−).

The ostiole is apical, and the hamathecium is inspersed with oil droplets, featuring filaments that profusely anastomose.

Additional specimens have been examined from Queensland, Australia, and Chapada do Araripe, Ceará, Brazil.