Diagnosis.  - 

Comparisons. -  

Subordinate taxa. - 

Distribution. - 

Taxonomic History and notes. -

Remarks. -  One of the more striking dichotomies in the nominate subgenus is that between the generally large species with many pectinal teeth and the generally small species with few pectinal teeth . Although there are exceptions in each group, the divergent tendencies in size and pectinal tooth counts, as well as in several coincident characters, are quite conspicuous. This dichotomy is also supported by the observations that the two groups are widely sympatric, whereas the species within each group are, with few exceptions, allopatric . However, one of the large species, Paruroctonus gracilior (Hoffmann,1931), is geographically removed and morphologically divergent from the other large species, and in various characters tends to link the large and small species. The link is completed by Paruroctonus becki (Gertsch and Allred,1965) among the large species and Paruroctonus stahnkei (Gertsch and Soleglad,1966)among the small species, each of which is intermediate to P. gracilior and most or all of the other species in their respective groups with respect to infragroup characters 1-3 (see infragroup diagnoses below) as well as in the number of retroinferior terminal setae on the telotarsi, the number of primary denticle rows on the pedipalp movable finger, and the development of denticles on the inferior carina of the cheliceral fixed digit . The various characteristics shared by P. gracilior and the remaining large species (i .e., infragroup characters 5-10) all appear plesiomorphic, relative to the outgroup subgenus Smeringurus, and thus do not necessarily support a closer relationship than one between P. gracilior and the small species, a relationship for which, likewise, no synapomorphies are known. Therefore, the classification that, in my opinion, best describes the available observations is one involving three infragroups; namely, gracilior, boreus (including P. becki), and stahnkei.