Hi Kevin,
Ahhh, the famous P. adspersus angusticeps

It seems that in 1982, some scientist named C. R. Parry decided to revise the genus Pyxicephalus. See if this is confusing:
Pyxicephalus adspersus edulis (Parry, 1982)
Pyxicephalus adspersus angusticeps (Parry, 1982)
Pyxicephalus adspersus (Parry, 1982)
So is P. edulis a subspecies or a distinct species or even the same species as P. adspersus?
Alan Channing (1994) says that P. edulis differs by its call, behavior, smaller size, shorter dorsal ridges and smoother skin. Lambiris (1989) considers P. edulis a subspecies and points out the following distinctive features: white spot on tympanum, bars on the upper lip and interorbital stripe (as mentioned in my article).