This genus can be told apart from Phrynus by observing the patella of the pedipalp, which in Phrynus has one small spine between the two largest, while Paraphrynus has two.
It can be distinguished from Acantophrynus by its lack of spines in the frontal region of the carapace.
The remaining member of the family Phrynidae, Heterophrynus, does not seem to be sympatric with any species of this genus.

There are about 18 species:
Paraphrynus aztecus (Pocock, 1894)
Paraphrynus baeops (Mullinex, 1975)
Paraphrynus carolynae Armas, 2012 
Paraphrynus chacmool (Rowland, 1973)
Paraphrynus chiztun (Rowland, 1973)
Paraphrynus cubensis Quintero, 1983
Paraphrynus emaciatus Mullinex, 1975
Paraphrynus grubbsi Cokendolpher and Sissom, 2001
Paraphrynus laevifrons (Pocock, 1894)
Paraphrynus leptus Mullinex, 1975
Paraphrynus macrops (Pocock, 1894)
Paraphrynus maya Armas, Trujillo & Agreda 2017
Paraphrynus mexicanus (Bilimek, 1867)
Paraphrynus olmeca  Armas & Trujillo 2018
Paraphrynus pococki Mullinex, 1975
Paraphrynus raptator (Pocock, 1902)
Paraphrynus reddelli Mullinex, 1979
Paraphrynus robustus (Franganillo, 1931)
Paraphrynus velmae Mullinex, 1975
Paraphrynus viridiceps (Pocock, 1894)
Paraphrynus williamsi Moreno, 1940
This genus can be told apart from Phrynus by observing the patella of the pedipalp, which in Phrynus has one small spine between the two largest, while Paraphrynus has two. It can be distinguished from Acantophrynus by its lack of spines in the frontal region of the carapace. The remaining member of the family Phrynidae, Heterophrynus, does not seem to be sympatric with any species of this genus.
There are about 18 species:
Paraphrynus aztecus (Pocock, 1894)
Paraphrynus baeops (Mullinex, 1975)
Paraphrynus carolynae Armas, 2012 
Paraphrynus chacmool (Rowland, 1973)
Paraphrynus chiztun (Rowland, 1973)
Paraphrynus cubensis Quintero, 1983
Paraphrynus emaciatus Mullinex, 1975
Paraphrynus grubbsi Cokendolpher and Sissom, 2001
Paraphrynus laevifrons (Pocock, 1894)
Paraphrynus leptus Mullinex, 1975
Paraphrynus macrops (Pocock, 1894)
Paraphrynus maya Armas, Trujillo & Agreda 2017
Paraphrynus mexicanus (Bilimek, 1867)
Paraphrynus olmeca  Armas & Trujillo 2018
Paraphrynus pococki Mullinex, 1975
Paraphrynus raptator (Pocock, 1902)
Paraphrynus reddelli Mullinex, 1979
Paraphrynus robustus (Franganillo, 1931)
Paraphrynus velmae Mullinex, 1975
Paraphrynus viridiceps (Pocock, 1894)
Paraphrynus williamsi Moreno, 1940
Paraphrynus