P. girardi was originally described and named as a species new to science by José Vicente Barbosa du Bocage in 1893.

[3] The specific name, girardi, is in honor of French-Portuguese zoologist Alberto Arthur Alexandre Girard (1860-1914).

[4] P. girardi occurs on the island of Annobón in Equatorial Guinea.

The species may also occur in the Republic of the Congo.

[2] The preferred natural habitat of P. girardi is forest.