In contrast to the related Phacops, Eldredgeops generally has a raised ridge along the ventral margin of the cephalon, the glabella is more inflated, the lateral parts of the preoccipital ring are rectangular (and not round), the palpebral area and palpebral lobe are larger than in P. latifrons (the type species of Phacops), and there is no fold right behind the posterior vertical row of lenses nor an isolated raised area just below the lenses.

[1] All phacopids died out in North America during the Kačák Event at the end of the Eifelian.

The phacopids returned to North America during the early Givetian with the emigration of Eldredgeops species from Morocco.

It was considered however that the post-Eifelian North-American relatives of P. rana differ sufficiently from those found in Africa and Europe to be assigned to a separate genus.

[1] Pre-Givetian North-American species previously included in Phacops have also been reassigned, such as P. cristatus (now referred to Viaphacops), P. microps and P. raymondi (now Kainops), P. cambelli, P. birdsongensis, P. claviger and P. logani (now Paciphacops).