Diagnosis: Haradon 1985 Diagnosis .—An infragroup of nominate subgenus Paruroctonus differentiated by : (1) cheliceral fixed digit with inferior carina confined distally, does not extend proximally to level of bicusp (see Gertsch and Soleglad 1966: fig. 33); (2) cheliceral movable digit with superior distal tine essentially triangular, inferior distal tine length/superior distal tine length ratio 3.1-3.2 (see Gertsch and Soleglad 1966 :fig. 35); (3) carapace length/cheliceral fixed digit length ratio 3.3-4.1 (rarely 4.2); (4) basitarsus III with five superior setae, including three distal plus two proximal (3+2 ; rarely 4+2, and only among arenicolous specimens); (5) pectinal teeth in males 23-32 (more than 95% with 24-32), females 15-21 (more than 95% with 18-21) ; (6) pedipalp movable finger length/palm length ratio in adult males and females 1.1-1.2 ; (7) carapace length/pectine length ratio in adult males 0.9-1.0, adult females 1.2-1.3 ; (8) humerus with three (occasionally four) inframedial macrosetae on proximal 3/5 of internal surface ; (9) pedipalp primary denticles, excluding proximal row, total 42-61 on fixed finger, 54-75 on movable finger ; (10) adult carapace length in males 4 .1-6.6 mm, females 4 .8-7.2 mm.
Key - Cheliceral fixed digit inferior carina does not extend proximally to level of bicusp; carapace length/cheliceral fixed digit length ratio 4.1 or less………....……….gracilior infragroup, P. gracilior
Distribution: Haradon 1985 Southeastern Arizona, eastward to Big Bend region of Texas, southward to Aguascalientes in México..
Included taxa: P. gracilior (Hoffmann 1931).
Notes: Haradon 1985 Comparisons: the boreus infragroup (below) differs in characters 1-4; the stahnkei infragroup (below) differs primarily in characters 1-4, but also significantly in 5-10.